EPA-650/2-73-044
 September 1973
Final Report to the Control Systems Laboratory of the U.S. Environ-
mental Protection Agency under Contract Number 68-02-0212,
September 1973
                                       Petrographic Characteristics
                                 and Physical Properties of Marls,
                                Chalks, ShellSf and Their Calcines
                         Related to Desu/furizafion of Flue Gases
                                                        Richard D. Harvey
                                                          Robert R. Frost
                                                      Josephus Thomas, Jr.
ILLINOIS  STATE  GEOLOGICAL  SURVEY,  Urbana,  Illinois

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Petrographic Characfer/sf/cs and Physical Properties
     of Marls, Chalks, Shells, and Their Calcines
      Related to Desu/fur/zaf/on of Flue Gases

        Richard D. Harvey, Robert R. Frost, and Josephus Thomas, Jr.
       Final Report to the Control Systems Laboratory of the U.S. Environmental
            Protection Agency under Contract Number 68-02-0212
                       September 7973
ILLINOIS STATE GEOLOGICAL SURVEY, Urbana, Illinois

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              PETROGRAPHIC CHARACTERISTICS AND PHYSICAL PROPERTIES
                  OF MARLS, CHALKS, SHELLS, AND THEIR CALCINES
                    RELATED TO DESULFURIZATION OF FLUE GASES
                                    CONTENTS


                                                                         Page

Abstract  	      1

Introduction  	      3
   Definitions of sample types and other terms  	      3
   General sample processing and methods of analyses  	      5
      Grain size by image analysis	      5
      Particle-size analysis by sedimentation   	      6
      Methods of mineral and chemical analyses  	      6
   Experimental methods of calcination and determination of
     pore structure and surface area	      7
      Pore structure by mercury porosimetry   	      7
      Apparatus for calcination and surface area measurements   ....      9
      Surface area measurements	     10
      Calcination conditions  	     11
      Experimental procedure  	     11
   Observations on calcination of samples   	     12

Marl Investigations   	     1^
   Uses and production of marl	     1^
   Sources and samples of marl	     1^
   Illinois marl deposits and samples    	     17
   Characterization of marl samples   	     18
      Grain size and particle size	     21
      Mineral and chemical analyses   	     27
      Moisture-density relations of marls   	     30
   Results and discussion of pore structure and surface
     areas of marls and their calcines	     31
      Pore structures and surface areas of marls	     31
      Pore structure and surface area of calcined marl	     31
         l6xl8-mesh particles   	     31
         170x200-mesh particles   	     ^0

Chalk Investigations	     ^3
   General characteristics of chalks and their origin   	     ^3
   Sources of samples of chalk and chalky limestone   	     ^3
      Kiobrara Chalk  	     ^5
      Greenhorn Limestone   	     ^5
      Austin Chalk    	     ^6
      Other chalk strata in Texas   	     ^7
      Annona Chalk  	     ^7
      Saratoga Chalk  	     ^7
      Selma Group   	     4-7
      Tertiary formations containing chalk and chalky limestone    ...     U8

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                                                                         Page

   Characterization of chalk and chalky limestone samples	      1*9
      Petrographic description   	      ^9
      Bulk density and crushing characteristics  	      50
      Mineral and chemical analyses  	      55
   Results and discussion of pore structures and surface areas
     of chalks, chalky limestones and their calcines   	      55
      Chalks   	      6l
      Chalky limestones	      66

Shell, Coquina, Caliche, and Sludge Investigations   	      71
      Sources of samples   	      71
      Characterization of samples and their calcines   	      72

Investigation of Carbonate Bocks Related to Previous
  Fluidized Bed Desulfurization Tests  	      78
   Samples and their relative decrepitation    	      79
   Characterization of samples   ..... 	      80
   Discussion of results   	      8U

Summary and Conclusions    	      84
   Marl	      8U
   Chalk and chalky limestone	      85
   Shell, coquina, caliche, and vaste sludge   	      86
   Conclusions regarding carbonates studied in relation
     to fluidized "bed desulfurization	      87

References   	      87
                                     TABLES


1.  Textural analyses of marls   	 .......     2k

2.  Mineralogy of marls	     28

3.  Chemical analyses of marls   	     29

k.  Harvard miniature compaction test results of marls   	     30

5.  Pore volumes and mean pore sizes of marls    	     32

6.  Pore structures and surface areas of marls and their
      calcines (l6xl8 mesh particles)  	     33

7.  Effect of calcination conditions on calcine pore structure
      and surface area of l6xl8 mesh particles of marl   	     38

8.  Comparison of test results on l6xl8 and 170x200 mesh
      particles of marl	     ^1

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                                                                         Page

 9.  Petrography and "bulk densities of samples  	    52-53

10.  Median particle sizes of pulverized samples  	       56

11.  Mineral analyses of chalk and chalky limestones  	    57-58

12.  Chemical analyses of chalks and chalky limestones  	       58

13-  Pore structures and surface areas of chalks, chalky
     limestones, and their calcines   	       60

lU.  Chemical and mineral analyses of shell and other
     carbonate samples  	       73

15.  Pore structures of shell and other carbonate samples
     and their calcines (l6xl8 mesh particles)  	       76

l6.  Petrography, pore structures, and decrepitation
     test results   	       79

17.  Chemical and mineral analyses  	       83


                                   APPENDIXES

 1.  Annotated bibliography on marls in the northeastern
     quarter of the United States   	       93

 2.  Sources of samples and remarks on the deposits   	      102


                                  ILLUSTRATIONS

Figure                                                                   Page

   1.  Examples of penetration-volume curves for (a) a single
       particle, (b) l6xl8-mesh particles, and (c) 170x200-mesh
       particles of marl	        8

   2.  Schematic diagram of apparatus used for calcination and
       for measurement of surface area	       10

   3.  Typical calcination recorder traces for (a) marls calcined
       at 850° C, (b) marls calcined at 950° C, and (c) chalks,
       limestones, and shells calcined at 850° C	       13

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                                                                         Page

Figure

   U.  Marl production pit  ......................    15

   5-  Localities of marls and other rocks sampled and the
       outcrop areas of principal chalk and chalky limestone strata .  .    l6

   6.  Particle-size distribution of selected marls   .........    25

   7.  Particle-size distribution of marl samples   ..........    26

   8.  Particle-size distribution of marl samples   ..........    26

   9.  Particle-size distribution of marl samples   ..........    27

  10.  Pore-volume curves for l6xl8 mesh particles of bog marl
       7132D and its calcine  .....................    35

  11.  Pore-volume curves for l6xl8 mesh particles of bog marl
             and its calcine  .....................    35
  12.  Pore-volume curves for l6xl8 mesh particles of "bog marl
       7137 and its calcine   .....................    35

  13.  Pore-volume curves for l6xl8 mesh particles of tufaceous
       bog marl 7133 and its calcines   ................    39

  l^t.  Pore-volume curves for l6xl8 mesh particles of lake marl
       7150 and its calcines  .....................    39

  15.  Pore-volume curves for l6xl8 mesh particles of bog marl
       7162C and its calcines   ....................    ho
  16.  Pore-volume curves for l6xl8 mesh particles and penetration-
       volume curves for 170x200 mesh particles of tufaceous bog
       marl 7133 and their calcines
  17-  Pore-volume curves for l6xl8 mesh particles and penetration-
       volume curves for 170x200 mesh particles of lake marl
       7150 and their calcines
  18.  Geologic time-rock classification of carbonate rocks studied . .    kh

  19-  Pore-volume curves for sample of chalk of the Marianna
       Limestone (7201) and its calcine   ...............    6k

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                                                                         Page

Figure

  20.  Pore-volume curves for samples of the Selma Group and
       their calcines:  Prairie Bluff Chalk (7206), Arcola
       Limestone Member of the Mooreville Chalk (720*0, and
       Demopolis Chalk (7230)  	    65

  21.  Pore-volume curves for samples of the Fort Hays Limestone
       Member of the Niobrara Chalk and their calcines   	    67

  22.  Pore-volume curves for samples of the Austin Chalk
       (7221A and 7222B), the Pecan Gap Chalk (7225), and
       their calcines	    68

  23.  Pore-volume curves for samples of the Annona Chalk
       (7226A and 7227B), the Saratoga Chalk (7228),
       and their calcines	    69

  2*t.  Pore-volume curves for samples of chalky limestones
       and their calcines:  Crystal River Formation (7120);
       Dessau Member, Austin Chalk (7219); Greenhorn
       Limestone (7210B)   	    70

  25.  Pore-volume curves for l6xl8 mesh particles of clam
       shell 712U and its calcine	    77

  26.  Penetration-volume curves for 170x200 mesh particles
       of carbonate sludge 7153 and its calcines   	    77

  27.  Calcine pore-volume curves for samples studied related
       to fluidized bed desulfurization  	    82
Plate

   1.  Common mollusks from Pleistocene marls  	    19

   2.  Characteristic textural features of lake marls  	    20

   3.  Characteristic textural features of bog marls   	    22

   k.  Selected types of particles that occur in marls   	    23

   5.  Typical textural features of lime in calcined marl	    37

   6.  Texture of chalk and a chalky limestone (F), coarse
       sparite in micrite	    51

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Plate                                                                    Page

   7.  Texture of micritic calcite in chalk samples  .........      5^

   8.  Texture of calcined (lime) samples of chalks
       shown in plate 7  .......................      62

   9.  Texture of the calcine (lime) from three types
       of calcite in chalks  .....................      63
  10.  Characteristic textural features of shells
  11.  A.  Eelatively smooth and coarse grains of lime in
       calcined shell material; B.  Relatively smooth and
       fine grains of lime in calcined sludge  ............     78

  12.  Typical textural characteristics of samples studied
       related to fluidized bed desulfurization  ...........     8l

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PETROGRAPHIC CHARACTERISTICS AND PHYSICAL PROPERTIES
     OF MARLS,  CHALKS,  SHELLS,  AND THEIR CALCINES
        RELATED  TO DESULFURIZATION OF  FLUE GASES
  Richard D.  Harvey, Robert R.  Frost,  and Josephus Thomas, Jr,
                               ABSTRACT
          Thirty-seven operating and other  pits in fresh-water  marl
 in the northeastern  quarter  of the United States and twenty-four de-
 posits  of chalk in chalky  limestone, four  deposits of shell and eo-
 quina, two deposits  of caliche, and a large carbonate  sludge refuse
 pile, all in the eastern part of the United States, were  sampled and
 studied in relation to their  potential use  in limestone (CaCOj) pro-
 cesses  for control  of  SC>2  emission  from  fossil fuel  combustion.
 Earlier studies had suggested the superiority of these materials over
 denser limestones in these  processes.  Each sample and  its calcined
 product (lime) were  investigated for their  petrography,  mineralogy,
 chemistry, pore structure,  and surface area.

          The occurrence of marl containing 80 percent  or more CaCO,
 is restricted largely to Pleistocene  age sediments that occur in the
 states around  the Great Lakes and  in Virginia.  Annual production of
 marl  in recent years has been approximately 2 million  tons; it is at
 present used entirely as agricultural limestone and for related soil-
 conditioning.   Production  could be  vastly increased  if demand in-
 creased.  Chalk and chalky  limestone are generally restricted  to the
 sedimentary rocks of Upper  Cretaceous and Tertiary age in the Kansas -
 Nebraska-Colorado area  and in the  southeastern  states from Texas to
 Florida.   Currently chalks  and chalky limestones in  most of  these
 states are used primarily in  the manufacturing of cement.
                                - 1 -

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                                 -  2 -

           Marls are  composed principally of  equant calcite  grains,
 most of  which are  less than  ^\i in  diameter,  that are  weakly ag-
 glomerated  and also of  mollusk shells, which consist  of aragonite.
 Together these  minerals provide  a CaCO, content  that is  most fre-
 quently between 80 and 90 percent.   Impurities are mainly quartz silt
 and organic  matter.  The pore volume  of marls  averages about  0.50
 ce/g, which corresponds  to a porosity of about 57 percent.  Calcina-
 tion of  marl at 850° C for 5 to 10 minutes  under high  gas flow in-
 creases the pore  volume about 0.2  cc/g marl	slightly more than the
 theoretical increase calculated from the CaCO, content because of the
 presence  of organic  matter.  The  physical  characteristics of  high
 pore volume and fine grain size in  marls and their  calcines indicate
 that they should have high  reactivities with  S02.   Such  character-
 istics of  solids are  of major importance  in most  gas-solid  inter-
 actions.  Because of the ease of their production and disaggregation,
 marls should  be given important consideration for   use in limestone
 scrubbing of flue gases at power plants in areas near  marl deposits.

           The grain  size and grain  shape of chalks  are essentially
 the same as those of marls.   Chalks  generally have a higher clay con-
 tent than marls  but contain less   quartz and  organic  matter.  Their
 pore volume varies,  mainly from one  chalk formation  to  another (0.04-3
 to  0.302 cc/g),  and  frequently it   is  0.3  ce/g less  than  that  of
 marls.   The calcines of chalks  have  pore  volumes  slightly less   than
 theoretical (pore volume  of   the chalk plus  0.2  times the  CaC03 con-
 tent of the chalk).   Judging from  pore-volume   data, chalks  and some
 chalky   limestones also  should have   higher reactivities   with
 gases than would  dense  limestones.
SO
  '2
          On the basis  of petrographic and  pore-structure analyses,
it is recommended that carbonate  shell materials not  be crushed and
used in S02 scrubbing;  however, their  calcines are probably  as re-
active as those of other carbonates.

          Carbonate waste  sludge resembles  marl in  many properties
and is potentially very reactive with S02, especially for  use in wet
scrubbing processes.

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                                    - 3 -
                                  INTRODUCTION


          Air pollution caused "by emission of sulfur oxides from power plants
is a major environmental problem, especially in highly industrialized areas.
Current research on this problem includes the use of limestone or lime to re-
act with sulfur dioxide (802) to prevent its emission.  Several processes based
on this chemical reaction have been proposed and are being tested at a number
of plants (Raben, 1973).  If one of these processes can be proved technically
feasible and reliable, it will be of considerable importance, because these
processes generally require the lowest capital and operating costs of any
prospective process of S02 control.  Of the various processes being considered
by power companies and others, the wet lime-limestone scrubbing process is
favored as the short-range solution for removal of S02 from stack gases
(Dibbs, 1971), especially if cost for waste sludge disposal can be held below
$3 per ton of wet sludge (Rochelle, 1973).

          Tests of Borgwardt (1970), Attig and Sedor (1970), and Coutant et al.
(l97l) of a sample of calcareous marl from Michigan and subsequent tests of two
other samples of similar marl (Harvey and Steinmetz, 1971) have shown that these
incoherent (soft) types of carbonate rocks have a relatively high capacity for
reaction with S02 at elevated temperatures such as those that occur in coal-
fired boilers.  Other relatively incoherent types, illustrated by two samples
of chalk and a sample of oolitic aragonite sand, also showed high S02 absorption
capacities (Harvey and Steinmetz, 1971).  It is thought that these types of
carbonates, upon heating, yield calcines having large pore volumes and large
surface areas.  These properties of the calcines are considered the major factors
affecting the relative S02 sorption capacities of samples of carbonate rocks.
In addition, a marl and a chalk showed high reactivity with S02 in a laboratory
wet scrubbing system (Drehmel, 1971).  Since so few samples have been tested,
detailed examination and testing of a number of these highly reactive rock types
are needed for efficient selection of carbonate materials for maximum desulfuri-
zation by limestone processes.

          The purposes of this study are to locate and sample a number of deposits
of marls, chalks, and sea shells; to characterize the samples petrographically
and chemically; to determine the grain-size and pore-volume distribution of the
samples; and to relate these properties to the pore-volume distribution and the
surface area of the calcined products.

          Samples of sea shells are included in this study because of their
similarities to the oolitic aragonite sand, which was determined to have high
absorption capacity in previous tests.  Both the oolitic sand and the sea shells
originate in nearshore marine environments; both consist of very fine grained
fibrous carbonate crystallites; and many sea shells consist of aragonite.


                Definitions of Sample Types and Other Terms

          It will be useful to clarify and define the types of carbonate
materials studied.  Marl is not a precise petrologic term, and geologists from
various parts of the world use this term to describe a variety of rocks.  The

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term marl as used in this report is restricted to a soft,  incoherent,  and very
fine grained material that is composed largely of calcite  and is  found in some
fresh-water lakes and "bogs.  A lake marl occurs "beneath a  considerable "body of
water (larger than 25 acres), and a bog marl occurs "beneath a tract of wet land
covered with dense vegetation and, in many places, with peat.  In this report,
the classification of a sample of marl as a lake or bog marl is based  on the
presence or absence of a natural lake at the sample locality.  If such a lake
does not occur in the specific locality of a sample, the sample is classified
as a bog marl.  It is recognized that most bogs evolved from a lake by over-
growth of vegetation.  However, this classification of marl was made in the
field at the time of sample collection and was considered  the most useful for
descriptive purposes.  Some marls have a pronounced sandy  texture, or  "feel,"
due to the presence of abundant particles in the size range of lOOp to 2000y
(microns).  These marls are referred to as tufaceous marls.  Some calcareous
shales, calcareous siltstones, and very clayey or silty limestones, many phos-
phatic, that occur in the southeastern part of the United  States  are described
in older geologic literature as marls.  These rocks, marine in origin, are
unlike the lake marls in composition and texture and are not classified as marls
in this study.

          Coquina is a type of carbonate rock that is composed mainly (> 75
percent) of shells and shell fragments and calcareous tests of invertebrates
that are partly lithified, or cemented, into a rock material.  Geologic
literature contains references to shell marls and marls that formed under marine
environments and contain abundant shells and shell fragments with various
amounts of sand, silt, and clay.  These do not resemble the fresh-water marls
in texture.  For clarity, the so-called shell marls, when  they contain abundant
calcareous shells, are classified in this report as coquinas.

          Shell is a type of carbonate material that consists of hard rigid
coverings of a variety of invertebrates that accumulate in large quantities
in certain localities under  shallow water.  A single shell is hard and consists
of calcite or aragonite crystallites.  The shells are not  cemented together.
They are dredged for commercial purposes from nearshore deposits, mainly along
the Gulf Coast in this country.

          Chalk, as used in this report, is a variety of limestone consisting
of very fine grained, porous, and partly incoherent carbonate rock composed of
50 percent or more CaCC>3 and containing abundant minute marine fossils.
Geologic literature contains references to chalks that are actually calcareous
siltstones, containing as little as 30 percent CaCC>3.  These rocks should not
be considered chalks and are excluded from this study.

          Calcine refers to a piece of chalk, marl, or other carbonate rock
that has been calcined, that is, heated sufficiently to convert CaC03 in the
rock to grains of lime (CaO).

          Pore structure is used in the broadest sense to include the properties
of pore volume, pore-volume distribution, and mean pore size in particles.

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                                    - 5 -
          Grain is a single crystalline unit or crystallite.   Microscopic
observation with polarized light permits analysis of the shape and size of
grains within rock materials.

          A particle may "be a single grain, hut more frequently consists of
several coherent grains.  For particles of colloidal dimensions,  the sedimentation
method of size analysis is particularly useful for obtaining  particle-size data.


                General Sample Processing and Methods of Analyses

          Samples were taken from selected deposits of marls, chalks, and other
carbonate rock types.  In some cases, samples were taken from stockpiles by
digging a shallow hole at several different places on the stockpile and removing
about half a liter of sample from the bottom of each hole. About 30 pounds of
sample was taken.  Many samples of marl were taken by hand-augering the upper
15 feet of the deposit.  In deposits of chalk and marl with observed differ-
ences in lithology between various strata or beds, separate samples,
distinguished by alphabetic letter, were taken and the thickness recorded.
Specific localities of the deposits, together with brief remarks concerning
the deposits and samples, are given in numerical order in appendix 2.

          A comprehensive series of laboratory tests and analyses were made on
the samples.  To provide small samples for the tests, the larger field samples
were dried, crushed, thoroughly mixed, and quartered.  Each sample was split
until approximately UOO grams remained.  One quarter of this  material was sieved
to obtain the l6xl8, l8xUO, 1*0x50, 50xl?0, and the 170x200 mesh fractions.  The
l6xl8, 40x50, and 170x200 mesh fractions were separated for pore-structure
measurements and calcination tests.  Thin sections were prepared from two size
fractions for petrographic analyses with a Quantimet image-analyzing computer.
Another quarter was further reduced to pass a 100-mesh screen.  This sample was
subjected to particle-size, mineralogical, and chemical analyses.  The particles
larger than 16 mesh were examined with the scanning electron microscope (SEM)
equipped with an X-ray analyzer.  Lastly, half of the i^OO-gram sample of marls
was subjected to Harvard miniature compaction tests (Wilson,  1970); and in the
case of chalks, bulk density determinations were made on pieces cut uniformly
from the block samples.


Grain Size by Image Analysis

          Microscopic measurements were made of the grain sizes of samples in
the l6xl8- and 170x200-mesh fractions.  Several hundred particles of each
fraction were embedded in epoxy, and thin sections approximately lOy thick were
prepared.  Fifty or more different fields of view in these sections were analyzed
with a Quantimet under cross-polarized light at a total magnification of x 1950.
Resolution was approximately 0.7y-  Thus, many grains less than ly in size were
not detected by the Quantimet.  However, the data obtained give representative
and relative measures of the grain sizes of the samples.

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                                    - 6 -
          Grain  size as measured with the Quantimet for each field of view
 is  expressed  in  terms of the mean chord length in microns.  The mean grain
 chord  length  (5) was computed from Quantimet output readings of grain area (A)
 and the grain area projection (P), according to:

                                  n - A L
                                  ° ~ P M

 where  L is the length of the magnified field of view scanned by the Quantimet
 and M  is the  magnification.  The results of analysis of 50 or more fields of
 view are averaged to give a mean grain chord length representative of the
 sample.  The  mean grain chord length is related to the maximum diameter (D)
 of  spheres according to:


                                  D = 1.27U C.

          Another parameter of the grain texture in rocks from Quantimet
 analysis is a measure of the total length of grain "boundaries .  Since the
 circumference (or boundary) of a circle is irD, the grain boundary length
 per unit area (B), expressed in mm/mmS, can be computed from P for each
 field  of view according to:
          For two  samples with the same size of grains, differences in observed
 (B)  reflect  differences in the mean shape or roundness of the grains in the
 samples .

          Quantimet analyses of electron micrographs can be determined in the
 same way as  the optical microscope fields of view.


 Particle-Size Analysis by Sedimentation

          Most samples of marl and chalk were subjected to particle-size
 analyses by  the sedimentation method.  The marl and chalk sample was crushed
 to pass 100 mesh (0.15 mm), mixed with distilled water, vigorously stirred for
 15 minutes, and allowed to settle undisturbed for particle-size analyses.  The
 weight percentage of solids in a constant volume of aliquot removed at certain
 periods of time by pipette from a constant depth in the slurry gave the data
 to calculate the distribution of particle sizes in the sample.  The data were
 plotted as a cumulative percentage versus particle size curve.  Interpolation
 of the curve at the 50 percent point gave the median particle size.


Methods of Mineral and Chemical Analyses

          Samples were analyzed for their mineral composition by X-ray dif-
 fraction of whole rock powders and by optical microscopic determinations .  The

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                                    — 7 —
percentage of insoluble residue was measured in warm IN HC1 acid and the
residue was analyzed "by X-ray diffraction to determine the types of clay
and other less abundant minerals present in the samples.

          Analyses of the chemical oxides were determined by the Analytical
Chemistry Section of the Illinois State Geological Survey.  The sodium oxide
(Na20) content was determined by neutron activation; K20 by flame photometry;
C02, total S (computed and listed as 803), H20 (weight loss at 110° C), and
organic carbon by gravimetric analysis; and the remaining oxides by X-ray
fluorescence spectrometry.  The loss on ignition can be figured from the  data
presented for each sample by finding the sum of the C02, 1^0, organic C,  and
S03 values.


              Experimental Methods of Calcination and Determination
                       of Pore Structure and Surface Area

Pore Structure by Mercury Porosimetry

          The mercury porosimeter used in these studies was a 15,000 psi
Model 5-7121 from American Instrument Company.  The 15,000 psi pressure limit
corresponds to penetration of mercury into pores 0.012JJ (1.2 x 10~D cm) in
diameter or greater.  The instrument measures the volume of mercury that  pene-
trates voids between particles and pores within particles as a function of
pressure.  With this instrument the total penetration volume, equal to the
total pore and void volume, must be less than 0.2 cc.  The instrument has proved
satisfactory for use in the present studies.

          The translation of penetration volume versus pressure data into
penetration volume versus pore and void diameter data requires that two
important parameters be known.  These are:  (l) the shape of the pores and
voids and (2) the contact angle between the mercury-material interface.  In
most mercury porosimeter measurements it is assumed that the pores and voids
are cylindrical and that, on the basis of experimental evidence, the contact
angle is 130 degrees.  The pressure readings are converted into the corresponding
pore  (or void) diameter, which is then plotted against the measured penetration
volume.  The resulting plot is a penetration-volume curve that can be used to
evaluate the void volume, the total pore volume, and the mean size of the true
pores.

          The interpretation of a penetration-volume curve obtained for a single
particle of material (fig. la) is usually simple.  Because no voids can be
associated with the single particle of material, the penetration-volume curve
is the pore-volume curve and, provided that all pores have been reached,  the
measured total penetration volume is equal to the .total pore volume of the
material.  However, the observed pore-volume curve may not be the true pore-
volume curve.  If the material contains rather large interior cavities connected
to the surface by narrow pores (usually called "ink bottle" pores), the cavities
will not be filled until the narrow pores can be penetrated and, hence, the true
pore-volume curve will not be observed.  The comparison of the pore-volume curve
for the single particle with the penetration-volume curves for other particle-size
fractions of the material can indicate whether or not "ink bottle" pores  are
present.

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                                    - 8 -
c
«
a.
                                                                            0.01
                                    Pore diameter (
      Fig. I - Examples of penetration-volume curves for (a) a single particle, (b) l6xl8 mesh
             particles, and (c) 170x200 mesh particles of marl.
           In  the present study,  as in most studies, it was more desirable to
use a large number  of particles  rather than a single particle in the pore-
structure  measurements.   The mesh sizes of particles chosen were l6xl8  (l200y
to lOOOy), 1*0x50 (i+20y to 300y), and 170x200 (98y to 7%0.  All mesh sizes are
U.S. Standard.   Most of  the measurements were made on the l6xl8 mesh fraction.
Although actual  use of the marls, chalks, and shells now being studied  would
probably require the material to be ground to minus 170 mesh (88y) in the
"limestone-injection" process for S02 removal, it will be seen that the pore
structure  created by calcination is nearly the same for 170x200-mesh particles
as for l6xl8-mesh particles.  However, it should be pointed out that the total
pore volume obtained for the l6xl8-mesh fraction of a marl or chalk cannot be
used simply to represent the total pore volume available in any smaller size
fraction of the  same material.  Because of the polygranular nature of these
particles, subdivision of a large particle will take place principally  along
pores, thereby reducing  the total pore volume within the resulting particles.
The lost pore volume would be converted into additional void volume between
particles.

-------
                                    - 9 -
          A major problem in correct interpretation of porosimetry data is  to
distinguish between void volume and actual pore volume.  Any agglomeration  of
small particles will create a considerable number of interparticle voids, and
unless the amount of mercury intrusion into the voids can be determined, the
pore-volume measurement will be erroneously high.  The penetration of mercury
into the voids between packed spheres is characterized by a rather abrupt
breakthrough pressure corresponding to the apparent pore diameter of the voids
and by subsequent gradual filling of the toroidal voids around the contacting
particles.

          At the beginning of the present study, penetration- volume measurements
were made on nonporous Iceland spar (pure calcite, density 2.71 g/cc) to enable
corrections to be made on the observed penetration values of marls and other
samples for interparticle void space and other factors such as mercury compressi-
bility.  These data showed that 90+ percent of the void space for l6xl8-mesh spar
was filled at the initial pressure of 1.8 psia (pounds per square inch absolute)
and that the remaining void space was filled in the 1.8 to 12 psia range,
corresponding to the lOOy to 15V pore-size range.  A small amount of additional
penetration volume was measured in the 12 to 15,015 psia range (l5y to 0.012y
pore-size range).  The penetration- volume data for Iceland spar were used to
correct other penetration-volume data.  A typical penetration-volume curve  for
l6xl8-mesh particles of marl is shown in figure Ib.  The first step in the  curve
represents the filling of voids , and the second step represents the filling of
pores within the particles.

          For 170x200-mesh particles of nonporous calcite most of the voids are
filled at 12 psia (l5y pores), but they are not completely filled until 200 psia
(0.9y pores) is reached.  These data were used as a zero-pore base line in
determining the true pore volume of the 170x200-mesh samples tested.  A typical
penetration-volume curve for 170x200-mesh particles of marl is shown in figure  Ic,
The large first step represents the filling of voids , and the second step repre-
sents the filling of pores within the particles .  Hence , pores much larger  than
lOy in lOOy particles cannot be distinguished from voids.  In practice, voids
larger than 15U (12 psia) were filled with mercury before any data were recorded.

          The mean pore size was determined from the pore-volume curve by
computing the mean of the pore sizes evaluated at the l6th, 50th, and 8Vth
percentiles of the distribution.  The mean calculated by this procedure more
adequately characterizes the distribution than does the mean calculated by  the
50th percentile alone (Falk, 1958).  The standard deviation (S.D.) was computed
from the pore sizes (S^) evaluated at the 5th, l6th, 8^th, and 95th percentiles
by means of

                           - S95 " S5   . S8^ ~ Sl6
                       '- ~    6.6          5       •

Apparatus for Calcination and for Surface Area Measurements

          A schematic diagram of the apparatus used for calcination of the
carbonate rocks tested in the present study and for subsequent measurements of
the surface areas of the calcines is shown in figure 2.  The U-shaped sample

-------
                                    - 10 -
           110 VOLTS
                                                               GAS EXIT
                       3-WAY STOPCOCK
                        DRYING
                        TUBES
                   -V////A-
 {•) NEEDLED • ) VALVES f •)
                         ATMOSPHERE
                                                                   SOAP
                                                                   FILM
                                                                   FLOW METER
! I


;

w_-»-j



THERMAL


CONDUCTIVITY
CELL
c
! i


: OIL BATH :
                                                               ROTAMETER



PLAT
SAMP
HOLD

FURNACE


NUM
LE
ER






PROGRAMMER j



I ^
rEMPERATURE
CONTROLLER






TE
                                                                             -110 VOLTS
                                                                         TEMPERATURE
                                                                          RECORDER
          Fig. 2 - Schematic diagram of apparatus used, for calcination and for measurement
                 of surface area (after Thomas and Frost, 1972).

holder  is made from platinum-5 percent rhodium tubing and is connected to the
apparatus with Swagelok "quick connect" fittings, which are cooled l>y an air
stream  during calcinations.  The furnace, capable of reaching 1000° C, can be
quickly raised to, or lowered  from, position around the sample holder.
Calcination takes place under  dynamic gas-flow conditions and the process is
monitored by recording the output of the thermal conductivity cell.  The recorder
is equipped with a Disc integrator for the measurement of the area under recorder
traces.   The apparatus and procedures are similar to those used by Thomas and
Frost (1971).
Surface Area Measurements

          The use of a flow  system (fig. 2) for  surface area measurements was
first described by Nelsen and  Eggertsen (1958).   For these measurements, the
3-way stopcock and the U-way valve were rotated  90 degrees from the  positions
shown in figure 2.  A known  mixture of helium  and nitrogen was passed over the

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                                   - 11 -
sample.  A dewar flask of liquid nitrogen was raised around the  sample holder
to greatly lower the temperature of the sample,  thereby causing  nitrogen to be
adsorbed from the flowing gas stream.  After about 10 minutes, the  dewar of
liquid nitrogen was removed, the sample was quickly warmed to room  temperature,
and the adsorbed nitrogen was then desorbed from the sample. The desorbing
nitrogen produced a standard gas chromatograph peak on the recorder.  The  area
under the peak was determined by the Disc integrator.  From previously prepared
calibration curves, the amount of nitrogen adsorbed was determined.  The
composition of the gas mixture (determined from  gas flow rates)  defined the
nitrogen adsorption pressure.  The flow rate of  nitrogen was then changed  to
measure the amount adsorbed at other nitrogen pressures.  The  classical BET
(Brunauer, Burnett, and Teller, 1938) equation was then used to  calculate the
actual surface area.

          In the present study, the surface area of each calcine was calculated
from a single adsorption point.  The surface areas of rock samples  were  calculated
from multiple adsorption points obtained by using an apparatus  similar  to  the
one shown in figure 2.  This apparatus is used only for surface area measurements
and can handle two samples for consecutive adsorption point measurements.


Calcination Conditions

          All samples calcined in the present study were calcined at 850° C under
a nitrogen flow rate of 100 cc/min.  The calcination time was  less  than Ik minutes.
Calcines of limestones and dolomites (unpublished data of Frost and Thomas)
produced under these conditions have large surface areas (20+ m2/g calcine) and
contain fine pores less than 0.2y in diameter.  Similar properties  have been
reported by Coutant et al. (l9Tl) in dispersed-phase reactor studies with cal-
cination times of 2 seconds or less.  According to D. C. Drehmel (personal
communication, 1971), calcination of three marls at  980° C, under  comparatively
less dynamic gas-flow conditions than those used in  this study, produced calcines
with much lower surface areas  (1.6 to 3.9 ni2/g calcine).

          Selected marl samples were calcined at 950° C under a nitrogen flow
rate of 100 cc/min to study the effect of calcination temperature  on calcine
pore structure and surface area.  Calcination times  were less than 6 minutes.
Three marls (7133, 7150, and 7162C) were calcined at 950° C under  a 10 percent
carbon dioxide-90 percent nitrogen  (by volume) gas stream at 100 cc/min.  A
calcination time of 10 minutes was used, but calcination was complete in less
than 5 minutes.  The three marls were also calcined  at  950° C for  60 minutes
under both the pure nitrogen and the 10 percent carbon  dioxide-90 percent nitrogen
gas streams.


Experimental Procedure

          A 0.2 to  0.3 g carbonate  sample was weighed  and placed in the sample
holder, which was then connected to  the  apparatus.   When a  stable  output signal
from the thermal  conductivity  cell was observed on the  recorder, the furnace
(preheated to 850°  C  or 950° C) was  raised over the  sample  holder.  The calcination

-------
                                   - 12 -
 process was completed in h  to  12 minutes and was monitored on the recorder.
 About 2 minutes after the apparent completion of calcination, the furnace was
 removed.  The sample holder cooled rapidly to room temperature.  The calcine
 surface area was then measured.  The calcined sample was removed from the sample
 holder, weighed, and transferred to a mercury-penetration cell for the pore-
 structure measurements.
                      Observations  on  Calcination  of Samples


           Three typical calcination recorder  traces are  shown in figure 3.  The
 trace shown in figure 3a is  representative  of chalks,  chalky limestones, and
 shells calcined at 850° C.   The  height  of the trace above the base line is
 proportional to the C02 concentration in the  gas  stream.  Hence, the area under
 the trace is proportional to the C02  content  of the carbonate sample.  There is
 no readily available explanation for  the small dip at  the front of the trace.
 The general shape of the trace suggests a receding shell calcination model.

           Traces typical of  lake marls  and  bog marls calcined at 850° C (fig. 3b)
 have three distinct regions.  The  large initial negative dip (cut off by a
 recorder stop) resulted from the decomposition of the  relatively large quantities
 of organic matter present in the sample.  An  appreciable quantity of CC>2 from
 carbonate decomposition was  included  in the negative peak, as evidenced by
 observed flow rates and time of  appearance  of the CC>2  peak, and by the consider-
 ably less area than expected under the  positive portion  of the calcination trace.
 A possible explanation for the two distinct positive regions on the observed
 trace is that they represent decomposition  of carbonate  grains widely differing
 in size.  Since carbonates will  not calcine in high concentrations of CC>2, the
 calcination of the largest grains  may be suppressed by the rapid calcination of
 the very fine grains.   It is  also  possible, because of the charring of the organic
 carbon,  that the suggested grain-size groups  are  actually one group and that
 traces like figure 3a, which has a small secondary hump, would be observed if the
 organic  carbon were absent.

           The  trace shown in  figure 3c  is typical of the traces of marls calcined
 at  950°  C  under both the pure nitrogen  and  the 10 percent carbon dioxide-90 percent
 nitrogen gas streams.   The effect  of  the increased temperature on the actual time
 for  complete calcination is readily seen by comparing  figures 3"b and 3c.  The
 calcination trace  at 950° C is characterized  by two regions instead of the three
 observed for calcinations at  850°  C.  The absence of the third region in the
 calcination trace  (950° C) must  be directly related to the increase in calcination
temperature.  At 950°  C,  calcium carbonate  will calcine  under considerably higher
 carbon dioxide  concentrations than at 850°  C.  Therefore, at 950° C, the rate of
calcination for all carbonate grains present  in a marl sample is so rapid that all
grains calcine more or  less at the  same time.

-------
                                   - 13 -
c
o
•o
c
o
                                   Time (m i n
      Fig.  3  -  Typical  calcination recorder  traces for  (a) marls calcined at

               850° C,  (b)  marls  calcined  at 950° C, and  (c) chalks, lime-

               stones,  and  shells calcined at 850° C.

-------
                                   - 1U -

                               MARL INVESTIGATIONS


                           Uses and Production of Marl
           During the early  1900's, considerable use was made of marl as a
 source of CaO for the manufacture of natural and portland cement.  Processing
 plants were located principally  in New York, Pennsylvania, Ohio, and Indiana.
 Production for use in cement  decreased in the 1930's, and by 19^0 little or
 no marl was used for this purpose.*  However, marl has long been used as a
 source of agricultural limestone, and marl, as defined here, continues to be
 produced almost entirely for  this purpose.  In 1968, 1,211,015 tons of calcareous
 marl  was produced in the United States  (U.S. Bureau of Mines, 1969).  In
 1969, production increased  to 2,1*90,000  tons  (U.S. Bureau of Mines, 1971).
 Indiana and Michigan are the  major marl-producing states.  In 1971» there were
 22 producers of marl at 2k  pits  in Michigan (Segall, 1972), and 29 pits were
 active in Indiana (Purdue University Cooperative Extension Service, 1971)-
 During the summer of 1971,  there were two active marl pits in Minnesota and
 one active pit in each of the states of  Virginia, New York, and Wisconsin.

           Marl occurs in basins  occupied by lakes and bogs.  The basins may be
 small, occupying a few'acres, or as large as several hundred acres.  Most
 deposits are of the order of  50  to 100 acres and 10 to 30 feet thick.  Production
 from most marl pits is small  compared to that from most limestone quarries.
 However, operators of marl  pits  report that if a new market or a new use for
 marl were developed, production  could be increased.

           With few exceptions, marl is mined by dredging a channel through the
 deposit and stockpiling marl  along the bank, allowing the water to drain
 (fig.  k).   The stockpiled marl is turned over occasionally to promote drying.
 However, the marl produced  from  one pit  examined was dry enough to be disked
 and then later loaded into  trucks for delivery; another pit was pumped
 sufficiently dry that the marl was loaded directly into trucks.


                            Sources and Samples of Marl


          Geologic  literature was surveyed to find localities of marls in the
contiguous states of the United  States.  With rare exception, all known lake
marls occur  in the  northeastern  part of  the country  (fig. 5).  These marls are
associated with  the  fresh-water  glacial  lakes and bogs.  An annotated bibliography
of the occurrences  and geology of marls  in the northeastern part of the country
is given in  appendix 1.

          Lake marls  consist  of  very fine grained gray to near white, soft and
incoherent mud-like material, mainly calcite (CaC^).  Marl frequently contains
*
  Coquina continues to be used in the manufacture of portland cement in Virginia
    and elsewhere and is included in U. S. Bureau of Mines production tables
    under the heading "calcareous marl."

-------
                                   - 15  -

                           Fig. 1 - Marl production pit.
organic remains of plants, the source of the gray color, and also scattered
mollusk shells.  In most deposits, some degree of stratification of marl occurs.
Snail shells are concentrated into a few lenticular beds 1 to 3 inches thick and
k to 10 feet in length, and other stratification is evidenced by thin inter-
laminations of dark and light colored marl.

          Lake marls in the areas around the Great Lakes are all geologically
very young, Pleistocene in age,* and CaC03 in the form of marl is being deposited
during spring months in at least one fresh-water lake in New York (Terlecky,
in press).  Many of the marl localities identified in the literature were
examined and sampled for this study (fig. 5), and the locations and specific
remarks on the samples and deposits are given in appendix 2.  In August 1971,
samples were obtained from all known marl deposits in commercial production in
Virginia, New York, and Minnesota and from most of the commercial deposits in
Indiana and Michigan.
  The Pleistocene Epoch covers the time interval popularly known as the "Ice Age,"
    which began approximately 2 million years ago and includes the Holocene
    (Recent) Stage.  Marl appears to be forming in some lakes today.

-------
                                             -  16  -

               upper Cretaceous chalk
               outcrop areas

               Kansas and
                 Nebraska:  Niobrara
                   Texas:  Austin Chalk
                 Arkansas:  Areas too small to outline

              Mi ssi ss i pp i
              ana Alabama:  Chalk formations in Selma
                          Group
Tertiary chalky  limestone and chalk
outcrop areas
Mississippi:

                                                                      Georgia:

                                                                      Flor ida:
            Vicksburg Group and
            Chickasawhay Limestone
            (01 igocene)

            Vicksburg Group and
            Chickasawhay Limestone
            (01igocene) and Jackson
            Group,  i ncIud i ng Oca I a
            Limestone (Eocene)

            Oca I a Limestone (Eocene)

            Oca I a Group and Avon Lime-
            stone (Eocene) and the
            01igocene Series of
            formations
Fig.  5 -  Localities  of marls and other rocks  sampled and  the  outcrop  areas  of princi-
           pal  chalk and chalky limestone strata.   Sources:   Alabama -  Copeland (1968);
           Florida - Vernon and Puri  (1965);  Georgia - Georgia  Division of Mines, Min-
           ing  and Geology  (1939); Kansas -  Kansas  Geological Survey (1964);  Missis-
           sippi - Bicker  (1969);  Nebraska  - Burchett (1969); Texas - Oetking (1959)-

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                                   - IT -
          Marl resources in Indiana are described and chemical analyses  of core
samples of five deposits are given "by Wayne (1971).

          The Ogallala Formation (Pliocene in age) of western Kansas contains
deposits of lake marl (Frye and Leonard, 1959).  Samples for study were  obtained
from two localities.  One was collected from an operating quarry in Ogallala
marl where the deposit (7217) was mined for its diatomaceous content by  the
NL Industries of St. Louis, Missouri.  The other was collected from a nearby
deposit (72l6); however, this sample was later proved in laboratory studies to
be a calcareous siltstone with a smaller calcite content than anticipated.

          Several deposits of marl and related soft and porous carbonates are
known to occur in widely scattered localities in the western states but  were
not sampled for the present study.  The following remarks will serve as  a guide
for further investigation in these areas.  In south-central Oklahoma, in the
vicinity of Ravia, marly and chalky limestones of the Baum Limestone (Lower
Cretaceous) occur in considerable quantities, and samples contain 93.1 to 99«5
percent CaC03  (Wayland and Ham, 1955)-

          In western Utah, according to William P. Hewitt of the Utah Geological
Survey, Salt Lake City (personal communication, May 28, 1971), impure marls
occur in sediments left by the former Lake Bonneville, north of Ogden.  Also in
Utah, a pisolitic and chalky limestone of high purity occurs in Tertiary-Pleistocene
sediments on the eastern slopes of the Confusion Range, west of Delta (W. Walker,
Marblehead Lime Co., Thornton, Illinois, personal communication, May 17, 1973).

          Lake marls occur in north-central and northeastern Washington.  These
are described  in some detail by Valentine  (i960, p. 58 and  59).

          In Nevada, according to Keith G. Papke of the Mackay School of Mines,
Reno, Nevada  (personal communication, June 3,  1971), extensive deposits of
relatively pure unconsolidated calcium carbonate occur in two areas.  One is in
the vicinity  of Pyramid Lake, and the other is in  southern  Nye County, north of
Ash Meadows.   The latter deposits were previously mined for whiting.

          Many rock types  described  in geologic literature  as marls  are sands,
calcareous siltstones, and calcareous claystone, all deposited in marine waters.
Many of these rocks are associated with  chalks in  the Upper Cretaceous rocks
from Texas to Alabama; examination  showed  they are  too low  in CaC03  content  for
inclusion in  this study.   Thus, the  Corsicana  Marl, Arkadelphia Marl, Marlbrook
Marl,  and Brownstown Marl  Formations were  excluded.


                        Illinois Marl Deposits  and  Samples


          Two deposits  of  marl  in Illinois are of  special  interest.   Marl was
produced  from a bog deposit  near  Chatsworth,  Illinois  (locality 7l62) ,  during
the late  1930's.  Samples  from  this  site were  obtained  from stockpiles  that
remain from  past  workings  (7l62 A-D).   F,xact marl  reserves  in this  locality

-------
                                   - 18 -
axe not known, "but it is thought that only a relatively small portion of the
marl was removed during past operations .  The bog is about 60 acres in area
and was reported at the time of production to be 2^ feet thick in the central
part.  A small lake now stands where the marl was previously produced.

          The other known sizable deposit of marl in Illinois occurs beneath
a peat  (Grayslake Peat) deposit near Batavia, Illinois, about 30 miles west of
Chicago  (locality 7163).  The peat is currently being produced from the surface
and processed by the Batavia Soil Builders Company.  Samples 7163A-C were
obtained from a boring near the northwest edge of the bog.  Marl was observed
to occur from 3 to more than 13.2 feet (the maximum extension of our auger).
Sample  Tl63D was taken from a pile of marl dug previously near the center of
the north end of the bog.  The bog occupies an area of about 230 acres and if
the marl averages 10 feet in thickness, about 10 million cubic yards of marl
are present  in this deposit.  As a cubic yard of marl weighs close to one ton,
this  deposit is estimated to contain about 10 million tons of marl.  The
topographic  quadrangle map of the area  (Geneva, Illinois) shows the presence
of other bog areas in the vicinity of Tl63 that which may contain marl.


                        Characterization of Marl Samples


          The distinction between lake marls and bog marls is based on the
presence  or  absence  of a natural lake immediately above the collection site.
The  samples  designated as lake marls  (app. 2) do not differ greatly from bog
marls.   Both types consist overwhelmingly of very fine grained gray to light
buff  calcite.  They are very soft and incoherent mud-like materials and
frequently contain organic remains of plants.  Conspicuously scattered through-
out marls are mollusk shells (pi. l), with specimens and varieties of gastro-
pods  being more abundant than those of bivalves.  Both pulmonate (with lungs)
and branchiate  (with gills) gastropods occur.  The mollusk shells are very eas-
ily broken, and in all specimens examined they consist of the aragonite form
of CaC03.  Gastropod specimens are frequently 1/2 to 1 cm across, whereas the
other types of shells present are usually 1 to 2 mm or less across.  The larger
shells are conspicuous in the marl because their color is milky white whereas
the surrounding fine-grained calcite is light to dark gray.  Marls containing
little or no organic matter are nearly white when dry.  The darker color is due
principally to the occurrence of organic matter and moisture.

          The major inorganic impurities in marls are quartz, as partly rounded
grains k\i to 30y in diameter, and a few similarly sized and shaped grains of
feldspar.  These impurities are present in nearly every sample of marl and are
scattered throughout the marl material rather than concentrated in certain
layers.  The abundance of these grains is proportional to the amount of SiC>2
and Al2C>3 observed in the samples, as will be discussed later.
          Study of lake marls by electron microscopy  (pi.  2, A-F)  shows the
character of the grains and the high porosity of the  samples.  The micrographs
shown illustrate characteristic textural features of  the lake marls studied.
Crystallite grain size, measured from more than five  micrographs of each  sample

-------
                                          -  19 -
A.  Pulmonate gastropod, Gyraulus
    altissimus  (Baker)
B.  Branchiate gastropod,  Amnicola
    leightoni (Baker)
C.  Bivalve, Pisidium sp.                            D.  Pulmonate gastropod, Physa sp.

                  Plate  1 -  Common mollusks from Pleistocene marls (x 10).

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                                             - 20 -
C.  Sample 7142
                           (x 2240)
D.  Sample 71J4A ,  5ti  ,   (x 1970)
E.  Sample 7158,
                      Plate 2  -  Characteristic  textural features of lake marls.

-------
                                   - 21 -
of the 1*4- lake marls, ranges from O.ly to more than l6y;  most grains  have  a
diameter between 0.5y and 2y.  In large part, these marls consist of  agglomerate
particles composed of several grains or crystallites weakly held together  to
form porous particles (especially noted in pi. 2F).  In some areas, grains and
particles are not clearly distinguished, such as in the right hand part of the
large particle in the lower left of plate 2A.  It is interpreted that the  nodes
present there are grains.  Similarly, the nodes on the particle in the center
of plate 2C are interpreted to be grains.

          Marl in bogs consists mainly of very fine grained calcite  (pi. 3, D,
E, and F) and resembles lake marl in all important respects.  Bog marl tends
to be somewhat coarser grained than lake marl.

          Tubular particles are found in 75 percent of the marls and  are usually
most abundant in bog marls.  These particles are about 1/H to 1 mm in diameter
and 1 to 10 mm long (pi. ^C).  The interior of these particles contains several
open channels that run parallel to the long axis.  Inspection of the  outer sur-
face of the tubules (pi. 3, A, B, and C) shows randomly oriented, interlocking
grains of calcite that are larger than most of the other calcite grains in the
marl.  These tubules are the most coherent particles in marls, although they
readily break apart when a few are rolled together between one's fingers.   When
these tubules are very abundant, the marl is designated as tufaceous  (app. 2).*

          Unusual and rare particles, found in a few samples of marls, are
spores (pi. kA); framboidal pyrite  (pi. Ufi)—spheroids lOy to 30y in diameter
that consist of crystals (mainly ly octahedrons in this case) of pyrite (
diatoms  (pi. to)—delicate, siliceous skeletons of aquatic algae, especially
abundant in 7162A; and ostracod carapaces (pi. ^E)—shells of minute bivalve
crustacean fossils.
 Grain Size and Particle Size

          Averages of the  50 or more values  of C  (mean grain  chord length) and
 of B  (grain boundary length) determined from petrographic thin sections by
 Quantimet procedures for each marl were computed  and  considered to be  character-
 istic of the sample  (table l).  In addition, many of  the scanning electron
 micrographs of specimens taken at extra high magnification were of sufficient
 quality for Quantimet analyses  (table  l).

          The Quantimet analyses show  the mean chord  length of the bog marls
 to range from 1.8y to 5-7y.  The average is  3.Uy.   The range  of C for  lake marls
 is 2.1y to li.Uy, with an average  (2.8y) slightly  smaller than the average for
 bog marls.  In many  samples, though not all, the  mean chord length measured on
 #
   Davis  (1901),  Thiel (1930),  and others have made detailed studies  of such  tubular
     structures and concluded that they were formed by the precipitation of CaCOs
     on the stems of Chara plants and, in places, several crystallites  were suf-
     ficiently interlocked to form a coherent sediment particle,  which  was deposited
     on the bottom of the bog after the death of the plant.

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                                               -  22  -
A.  Sample 7128A
(x 3020)
                      B.   Sample 7133      5n      (x  2580)
C.  Sample 7133 .   5n     (x 2150)
                      D.   Sample 715IB ,     5>i    |   (x  3250)
 E.  Sample 7163B ,  5n  t   (x. 1890)                    P.  Sample 7163B  ,  5n   |   (x 2350)





                        Plate  3  -  Characteristic  textural features of bog marls.

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                                             -  23  -
A.   Spores in ?l62C (x2500)
B.  Framboidal pyrite
C.  Tubules in tufaoeous marls (x20)
D.  Diatom Cymbella sp. (x!990)
                                      E.  Ostraood valve (x2W)





                       Plate 4 - Selected types  of particles  that  occur  In marls.

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                                           TABLE 1 	 TEXTURAL ANALYSES  OF MARLS
Sample
number
TlZfi*
7127A
7127D
7128*
7128B
7129
7130
7131A
7U1B
7131C
7132A
7132E
7132C
7132D
7133
7134A
7136
7137
7138
7139
7110
7141
7142
7143A
7144A
7145A
714 6A
7147A
7148
7149A
7149B
7150
7151A
7151B
7151C
7152
7154
7155
7157A
7157B
7157D
7158
7159
7160
.7161
7162A
7162B
71 &C
716ZD
7163A
7163C
Quant imet
Mean grain chord
Thin sections*
3.8
6.6
2.6
4.2
5-7
3-5
3-3
3.2
2.7
4.0
3.8
4.3
2.7
3.1
4.1
2.2
3.0
3.0
2. It
2.7
3.2
2.7
2.1
2.6
2.6
2.1
3.0
2.8
3.1
2.8
—
4.4
3-3
2.9
2.7
1.8
3.9
3-0
3.2
3.1
2.5
2.4
2.5
3.1
3.5
4.7
1.0
4.0
3.9
—
4.0
length, 5 (|i)
Electron
micrographs
—
—
—
. —
1.5*
—
—
—
—
~*~
—
2.05
2.22
1.8K
I. at
1.71
—
—
3.7*
3.11
—
2.85
1.81
1.41
~~
1.53
—
2.17
1.62
2.21
2.37
0.41
4.05
1.48
2.00
	
	
	
2.85
. T
—
1.30
2.66
—
—
3.90
2.01
1.54
1.72
1.72
"^
results
Total grain boundary length, B (mm/mm )
Thin sections
2945
2964
2185
2622
2394
2698
2926
3059
2090
3002
4180
1881
2964
2964
2375
2983
2052
3610
3211
2185
2679
2489
2888
2812
2527
2755
3192
2926
3078
2432
—
2869
1254
2774
4237
U294
2546
2831
3686
1900
1672
1824
1938
2546
—
1634
1463
2831
1330
—
1976
Electron
micrographs
—
—
—
—
680
—
—
—
—
—
—
611
1264
950
482
876
—
1083
447
667
—
755
965
1300
918
966
—
740
1103
842
849
1161
389
1008
848
—
—
—
794
—
—
1308
742
—
—
497
453
783
617
702
- -
Median
particle
sizet
(nl
40.0
—
—
—
42.0
—
—
—
—
~~-
—
—
—
8.2
22.0
—
—
6.7
35.4
~
30.0
10.5
24.2
22.3
—
—
—
—
—
39.0
22.1
7-6
—
—
~~~
29-5
—
—
9-9
• —
—
—
—
—
—
—
—
—
—
—
8.6
•Excludes grains  less  than l|i  in diameter, the limit of optical resolution of  the microscope.
IThe size corresponding  to the 50J( point on the cumulative curves (figs.  6-9); determined by sedimentation methods on
 samples dispersed and vigorously stirred in water for 15 minutes.

-------
                                     -  25  -
the electron micrographs is smaller than that from the thin  sections of the same
samples.  Two  disadvantages are inherent in an analysis "by electron microscopy:
(l) to obtain  a representative sample of grains, one must take  a very large
number of micrographs, and (2) the  contrast of the grains is not sufficient in
many micrographs to obtain accurate results with the Quantimet.

          The  results of particle-size analyses are shown graphically in
figures 6 to 9.   Interpolation of the curves at the 50 percent  point gives the
median particle size listed in table  1.   Some marls, especially the tufaceous
marls 7128B  (fig. 7) and 71^9A (fig.  8)  have particle-size distributions with
median values  up to itOy.  Clearly the vigorous stirring in water did not disperse
a sizable fraction of the particles in these samples.  For comparison, the
particle-size  distributions of three  limestones (Types 2, 3, and k in Harvey
and Steinmetz, 1971) crushed and pulverized for 2.5 hours in a  ball mill are
shown in figure 6.  It is clear that  the ball milling of dense  limestones does
not yield a  size distribution as fine as that observed for marls.
      too
                  Lake or bog marl

                  Tufaceous mar

                  Limestone
      20 -
                                                                      64
                                        Particle size (
              Pig. 6 - Particle-size distribution of selected marls.  For comparison,
                      results are also shown for three coherent and  hard limestones
                      (Types 2, J>, and b, Harvey and Steinmetz, 1971) that were
                      crushed and pulverized for 2.5 hours in a laboratory ball mill.

-------
                                      -  26 -
  IOO
                   I         2
                                      Particle  size ( fi)
                Fig. 7 - Particle-size distribution  of  marl samples.
  100
o    —
      O.5
                                     Particle size (p)
               Pig. 8  -  Particle-size distribution of marl samples.

-------
                                   - 27 -
     100
                                  Particle size ( JJL)

               Fig. 9 - Particle-size distribution of marl samples.
Mineral and Chemical Analyses

          The results of mineralogical analyses of marl samples are shown in
table 2.  The major mineral component in the samples  is calcite, the rhombo-
hedral form of CaC03.  Trace and minor minerals in marls  (table 2) are quartz
(in the form of silt grains k\i to SOy across); feldspar (silt); aragonite, which
occ-urs in the fossil shells common in marls; dolomite; pyrite; and clay minerals,

          Results of chemical analyses of all but the most  impure samples are
shown in table 3.  In addition to those oxides shown  (table 3), trace amounts
of Ti02 and MnO were detected in several of the samples.  The higher Ti02 values
(between 0.11 and O.U3 percent) were observed in the  most silty (quartz) samples.
All samples containing less than 20 percent Si02 have less  than 0.10 percent
Ti02-  MnO content was determined on all samples.  Sample 7129 contained 0.22
percent.  Three samples contained 0.05 to 0.06 percent MnO  (7130, 7133, and
7138).  All other samples  contained less than O.OU percent  MnO.
          The two columns on the far right  in  table  3  are values  calculated  from
loss-on-ignition data and the CaO values.   The "CaO  in calcine" represents the
weight percentage of the CaO in the sample  after being heated to  1000°  C.
      values refer to the oven-dried sample.
                                                                  The
percent.
silica.
 For the marls, the silica  (SiC^) content ranges from nil to  55-6
 Approximately half the samples of marls have  less  than  8 percent
Alumina values in the marls range from 0.03 to 6.79 percent.   Of 38

-------
                                                        -  28  -
                                             TABLE 2 — MINERALOGY  OF MARLS
Sample number
712 6A
712 6E
7127A
7127B
71270
7127D
7128A
7128B
7129
7130
7131A
7131B
71310
713 2A
7132E
71320
7132B
7133
713»A
7135
713o
7137
7138
7139
"Ito
7111
71H2
7l«
71 KM
71U5A
7146A
7M"A
7118
71<49A
71U9B
7150
7151A
7151B
7151C
7152
715"
7155
7156
7157A
7157B
71570
7157D
7158
7159
7160
7161
7162A
7162B
7162C
71 (&>
7163A
7163B
7163=
71°3D
7217
Major
caleite
calcite
quartz
quartz
quartz
ealeite
calcite
calcite
calcite
calcite fi: quartz
calcite
calcite
quartz & calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite & quartz
calcite
calcite
calcite
ealcite
calc ite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
ealcite
calcite k quartz
calcite
caleite
calcite
calcite
calcite
calcite
calcite & quartz
quartz
calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
calcite
Minor*
aragonite & quartz
—
calcite & clay
clay
clay & dolomite
—
quartz
—
quartz
~~
quartz
quartz
dolomite & feldspar
—
~
—
—
—
quartz
— _
dolomite
quartz
—
quartz
~
_
—
—
quartz
_
quartz
quartz
gypsum
—
~
quartz
—
quartz
—
quartz
quartz
quartz
—
quartz
"
—
quartz
—

dolomite
calcite, dolomite, i feldspar
quartz
—
—
quartz & aragonite
aragonite & quartz
aragonite
aragonite & quartz
quartz & aragonite
quartz
Trace*
—
aragonite
feldspar
feldspar
calcite
—
—
—
—
dolomite
aragonite & feldspar
feldspar
clay
feldspar (?)
™~
—
—
—
pyrite

feldspar (? )
—
quartz fc aragonite
—
quartz
quartz, dolomite, & aragonite
quartz & dolomite
aragonite, quartz, & dolomite
dolomite
quartz
feldspar
—
—
quartz
aragonite
dolomite 4 feldspar
—
dolomite & pyrite
quartz
aragonite
aragonite
aragonite
aragonite & feldspar
aragonite
quartz, aragonite, & dolomite
quartz
dolomite
quartz & aragonite
—
aragonite
aragonite * clay
aragonite
quartz, argonite, & feldspar
dolomite (?)
feldspar (?)
dolomite S: pyrite
quartz
dolomite
dolomite
limonite A: magnetite
•Bash indicates that no minor and/or trace minerals were observed.

-------
                    TABLE 3 — CHEMICAL ANALYSES OF MARLS
(Analyses by Analytical  Chemistry  Section,  Illinois State Geological Survey)
Sample
number
7126A
7128B
7129
7130
7131B
7U2D
7133
7134A
7135
7137
7138
7139
7140
7141
711*2
71U3A
7144A
7145A
714 6A
7149A
7149E
7150
7151A
7151B
71510
7152
7155
7156
7157A
7158
7159
7160
7161
7162A
7162B
71620
7162D
7163A
7163B
71630
7163D
7217
S10
2.46
2.34
26.9
40.5
13.5
1.21
1.59
4.33
0.28
1.38
0.43
10.6
0.85
1.70
1.40
0.32
4.85
1.53
9-95
0.41
0.83
7.99
0.55
2.83
1.80
1.17
7.82
35-4
12.9
6.42
8.88
48.7
55.51*
17.6
8.45
3.43
22.0
14.4
6.74
10.88
12.39
19.6
Al 0
1.09
1.13
5.91
5.79
2.13
0.28
0.51
1.08
0.15
0.47
0.23
2.16
0.08
0.89
0.22
0.12
0.73
0.1*4
1.38
0.17
0.12
0.83
0.24
0.19
0.03
0.34
0.15
4.19
2.27
0.66
0.77
6.79
6.52
4.54
1.41
0.43
3.72
1.55
0.98
1.87
1.86
1.38
Fe2°3
0.77
0.27
1.57
3.15
0.89
0.13
0.16
0.1*7
0.12
0.40
0.36
1.05
0.25
0.58
0.66
0.49
0.54
0.77
0.95
0.13
0.17
0.47
0.99
1.23
0.42
0.20
0.10
1.09
0.85
0.65
0.66
2.46 '
2.83
1.43
1.48
0.86
2.02
1.13
1.11
2.11
1.29
0.20
MgO
1.36
nil
1.62
2.26
1.33
0.03
0.53
0.64
0.38
0.19
1.18
1.16
1.36
1.75
1.27
1.18
0.99
1.46
1.25
1.69
1.58
1.16
1.01
1.33
1.38
1.80
1.33
1.65
1.08
3.05
2.26
3.69
1.62
1.52
1.55
1.07
1.47
0.9
1.07
2.99
1.81
nil
CaO
49.4
50.5
38.1
23.3
40.2
51.7
51.5
49.01
1*7.98
52.7
51.3
42.76
50.9
46.2
1*9.2
51.1
47.5
48.0}
41 . 02
52.2
50.59
46.6
41.7
47.69
49.7
50.3
46.24
26.16
42.26
44.86
41.0
17.08
12.55
35.8
40.7
48.13
29.98
40.6
44.7
38.8
40.3
42.34
Na 0
0.051
0.047
0.11*7
0.546
0.331
0.027
0.041
0.091
0.030
0.019
0.023
0.186
0.025
0.065
0.037
0.025
0.103
0.055
0.166
0.030
0.030
0.054
0.044
0.034
0.036
0.036
0.108
0.048
0.196
0.164
0.140
0.701
0.890
0.227
0.129
0.046
0.238
0.25
0.13
0.10
0.11
0.12
K 0
2
0.46
0.12
0.40
1.20
0.49
0.05
0.10
0.15
0.04
0.24
0.03
0.311
0.01
0.06
nil
0.02
0.06
0.02
0.17
nil
nil
0.06
0.02
nil
0.01
nil
0.10
0.65
0.27
0.07
0.01
0.99
1.14
0.39
0.26
0.07
0.48
0.28
0.21
0.57
0.53
0.27
v*
2.03
2.56
2.59
0.03
2.79
1.71
1.39
14.22
5.19
1.61
1.88
1.64
1.88
4.14
2.93
2.91
2.40
4.17
5.33
1.25
2.21
1.82
9.32
3.10
2.14
1.68
2.40
3.84
2.20
3.01
4.03
1.88
4.27
4.17
5.88
2.87
7.75
3.27
3.10
4.07
2.78
1.82
CO
2
40.97
39.08
18.24
19.84
33.15
40.89
40.17
36.94
36.50
4] .09
41.61
34.50
'11.78
37.30
39.78
40.40
37.98
37.99
32. >*5
42.55
41.69
38.24
31.56
37.56
1*0.99
41.77
37.89
20.99
34.32
36.95
34.00
16.43
10.67
29.06
31.88
39-24
23.14
32.84
36.32
33.65
33.10
32.97
SO
3
0.06
1.74
0.18
0.36
0.28
1.20
1.70
0.15
1.48
0.30
0.12
1.97
0.06
0.13
0.23
0.15
0.13
0.12
0.57
0.07
0.18
0.06
0.55
0.39
0.19
0.08
0.05
0.06
0.03
0.27
0.20
0.12
nil
0.62
0.24
0.16
0.61
0.09
0.35
0.27
1.07
nil
Organic
carbon
0.96
1.90
2.83
2.53
3.72
1.56
1.24
1.65
6.29
0.40
1.74
2.50
1.65
6.82
2.99
2.99
3.49
4.30
5.91
0.64
1.57
1.48
13.24
4.86
2.07
1.1*5
2.65
4.77
2.24
2.94
7.89
0.85
3.20
4.45
6.64
2.57
8.50
3.89
4.44
4.00
4.34
0.05
CaO in
calcine
88.2
89.1*
49.9
30.0
66.6
92.7
90.0
85.5
92.4
92.6
93.7
69.7
93.1
87.6
90.6
95.2
84.6
89.7
72.8
94.0
92.8
79-7
90.9
87.5
90.7
91.3
81.0
37.2
69.0
78.6
75.8
21.1
15.3
57-4
73.2
87.0
49.5
67.7
79.6
66.6
67.3
63.8
Caco
88.2
90.1
68.0
41.6
71.7
92.3
91.9
87.5
85.7
94.1
91.6
76.4
90.8
82.5
87.8
91.2
84.8
85.7
73.2
93.2
90.3
83.2
74.4
85.1
88.7
89.8
82.5
46.8
75.5
80.1
73.2
30.5
22.4
63.9
72.6
85.8
53.5
72.5
79-8
69.3
71.9
75.6

















1
ro
MD
i























-------
                                    - 30 -


samples of marl analyzed,  23  contain less than 0.89 percent A1203.  It is
estimated that one-fourth  to  three-fourths of the alumina occurs in silt-size
feldspar grains and that the  remaining trace amounts are in clay minerals.  Few
marls contain more than 0.15  percent Na20, probably present in clays.  The MgO
occurs mainly in dolomite  grains  detected in many marls.  Most marls contained
from 1 to 6 percent organic carbon, "but one sample (7151A) had more than
13 percent.


 Moisture-Density Relations of Marls

           To evaluate the possibility of successfully predicting the pore
 structure and surface area of marls and/or other important properties  related
 to the reactivity of marls and their calcines with SC>2,  a density  measurement
 was deemed important.  Because marls are fine grained and have  soil-like
 properties and most marl deposits under exploitation contain  about 50  percent
 water before being excavated, a moisture-density relations test  (commonly  called
 .the "Standard Proctor Test")  was thought to be useful.   Because  of the small
 quantity of sample available, the miniaturized Proctor  test—the Harvard  compac-
 tion test (Wilson, 1970)—was selected and was run on most of the  marls.   The
 results are listed in table 4.  The optimum dry density and corresponding
 moisture content were taken from the maximum point of a density versus moisture
 curve determined for each sample.  Preliminary evaluation of  these results
 indicates that samples with low density have high pore  volumes  and high organic
 carbon and H20 contents.


          TABLE 4 — HARVARD MINIATURE COMPACTION TEST RESULTS OF MARLS
                             Optimum density                 Moisture content
      Sample                     (g/cm )                          (%)
      7132D                       1.20                          38
      7133                        1.1?                          36
      7134A                       1.1?                          44
      7137                        1-57                          24
      7140                        1.17                          41
      7141                        0.99                          53

      7142                        1.03                          53
      7144A                       1.04                          51
      7145A                       0.91                          60
      7146A                       0.91                          58
      7149B                       1.07                          48
      7150                        1.25                          38

      7153                        1.23                          38
      7157*                       '1.23                          38
      7158                        0.99                          57
      7159                        0.96                          54
      71630                       0.96                          56

-------
                                   - 31 -

           Results and Discussion of Pore Structures and Surface Areas
                           of Marls and Their Calcines
Pore Structures and Surface Areas of Marls

          For a majority of the samples, only the l6xl8-mesh size fraction of
particles was tested.  However, for selected samples, other size fractions
were also tested.  The pore-structure data are summarized in table 5-

          The pore volumes of the lake and bog marls range from 0.21 to 1.08
cc/g, with a majority of the values in the 0.3 to 0.6 cc/g range.  The pore
volumes of the tufaceous marls are on the low end of the pore-volume range for
marls.  Variation in pore volume exists "between samples of marls taken from the
same deposit, especially 7126, 7131, 7151, 7157, and 7l62.  These differences
are probably due to the variations in contents of quartz and organic matter.

          The mean pore-size values (O.U7U to 5-80y) vary significantly between
the samples tested—in some cases, even between samples from the same deposit.
The size of the pores in the marls is rather evenly distributed from O.ly to
larger than 10u in diameter.  The average of the mean pore sizes of the lake
and bog marls is 1.7y«

          With the exception of marls 7129 and 7132D, the pore volume of the
170x200-mesh particles is less than that of the l6xl8-mesh particles, as
expected.  It is possible that the pore volumes listed for 170x200-mesh particles
of 7129 and 7132D still contain appreciable void space volume and/or that the
pore volumes of the l6xl8-mesh particles are low.

          The estimated average pore size for the 170x200-mesh particles is less
than the mean pore size calculated for the l6xl8-mesh particles of the same
sample except in sample 7132D.  The larger pores (>15y) present in the l6xl8-mesh
particles shift the mean pore size to a higher value, but these large pores
are not detected in measurements of the smaller particles.

          The surface area values for the marl samples are given in table 6.


Pore Structure and Surface Area of Calcined Marl

          A few of the samples, the pore structures of which were determined,
were not calcined as part of the calcination tests.  The  samples eliminated
from the calcination test program are of low purity  (<70  percent CaC03 content),
and all contain in excess of 20 percent quartz.


l6xl8-Mesh Particles

          Pore-volume and surface-area data for the l6xl8-mesh fraction of
marls and their calcines  (850° C) are given in table 6.   The calcine pore-
volume and surface-area data were determined on calcined  marl samples, but the
values in table 6 are reported in terms of "per g  (gram)  marl" used to prepare

-------
                                                 TABLE 5 — PORE VOLUMES AND MEAN PORE SIZES OF MARLS

Sample
number
Hash
size
(U.S.)
Pore
volume
(oo/g)
Mean
pore size
(n)
Standard
deviation
(u)
7126A 16x18 0.2325 ' 1.65 0.09
7126A 170x200 0.1500 0.60» . —
7126B 16x18 0.3720 5.80 0.13
7127A 16x18 0.1740 0,1*3 0.16
7127B 16x18 0.1235 0.16 0.16

Sample
number
714 9A
Mesh
size
(U.S.)
Pore
volume
(oo/g)
Mean
pore size
(n>
S tandard
deviation
(n)
16x18 0.1*099 ^-SS Otl1*
7149B 16x18 0.5808 2.14 0.21
7150 1 piece 0.1*658 1.25 0.45
7150 16x18 0.1*721* 1.30 0.24
7150 170x200 0.2500 0.80*
71270
7127D
7127D
7128A
7128B
7128B
7129
7129
7130
7131A
7131B
71310
7132A
7132B
71320
713 2D
7132D
7132D
7133
7133
7133
7134A
7135
7137
7138
7139
7140
7141
7142
7143A
7144A
7145A
714 6A
7147A
7148
l6xl8
3 pieces
16x18
16x18
16x18
170x200
16x18
170x200
16x18
16x18
16x18 •
16x18
40x50
40x50
16x18
1 piece
16x18
170x200
1 piece
16x18
170x200
16x18
16x18
16x18
16x18
16x18
16x18
16x1 8
16x1 8
16x1 8
16x1 8
16x18
16x18
16x18
16x1 8
0.1375
0.2880
0.2505
0.1990
0.2080
0.2000
0.1385
0.2100
0.2735
0.5745
0.5700
0.2335
0.4535
0.3995
0.4865
0.4667
0.3805
0.5680
0.3904
0.3150
0.0700
0.4905 '
0.5740
0.2770
0.5440
0.5225
0.4840
0.6725
0.5505
0.5750
0.5545
0.6250
0.5435
0.6189
0.1260
0.16
4.21
1.43
1.51
1.43
1.00*
1.38
0.60*
0.81
0.50
0.57
0.35
0.84
3.45
0.87
0.58
0.86
2.00»
3.13
4.44
1.00*
1.21
1.63
0.47
1.28
1.31
1.34
1.72
1.22
1.68
1.27
1.07
0.69
1.12
4.26
0.16
0.12
0.19
0.15
0.20
—
0.17

0.37
0.45
0.33
0.28
0.38
0.22
0.26
0.28
0.24
—
0.23
0.15
—
0.42
0.16
0.23
0.27
0.37
0.34
• 0.22
0.38
0.18
0.36
0.27
0.26
0.31
0.11
7151A
7151B
71510
7152
7154
7155
7156
7157A
7157B
71570
715 7D
7158
7159
7160
7161
• 7162A
7162A
7162A
7162B
71620
71620
71620
7162D
7163A
71630
71630
7163D
7163D







16x18
16x1 8
16x18
16x1 8
16x1 8
16x1 8
16x1 8
16x18
16x18
16x18
16x1 8
16x18
16x18
16x1 8
16x1 8
1 piece
16x18
170x200
16x18
16x1 8
40x50
170x200
16x18
16x18
I6xl8
170x200
3 pieces
16x18







0.5997
0.5732
0.4460
0.3995
0.6390
0.4205
0.4580
0.3670
0.3580
0.5000
0.4005
0.5045
0.6220
0.2190
0.2135
0.7942
0.5125
0.3200
1.0780
0.9340
0.7825
0.3200
0.7450
0.7750
0.5910
0.3400
0.8311
0.7190







2.58
1.15
0.78
1.07
3.22
2.25
1.93
1.38
0.60
0.90
0.70
1.02
1.28
2.06
0.83
5.65
2.98
1.50*
3.98
3.10
2.66
1.50*
3.38
1.70
2.64
0.80*
2.72
2.44







0.23
0.33
0.51
0.32
0.17
0.15
0.24
0.29
0.42
0.38
0.29
0.26
0.33
0.16
0.26
0.22
0.15

0.19
0.24
0.17

0.16
0.17
0.19
—
0.16
0.15







*An estimated mean pore  size.

-------
                                  TABLE 6 — PORE STRUCTURES AND SURFACE AREAS OF  MARLS AND THEIR CALCINES  (16x18 MESH  PARTICLES)



Sample
number
Marl



Type


volume
(cc/g)

».
pore size
(n)

c, . , ,
deviation
(u)

r, ,-,
area
(m /£)
Cal cined marl
Observed
,
increase*
{ cc/£ marl )
Theoretical
„
increase**
( cc/£ marl )
Pores ':-0. l\i diameter"^

Pore volume
( r;c/g marl )
7128B Tufaoeous bog marl 0.208 1.43 0.20 — 0.202 '}. 180 ?
7131B Bog marl 0.570 0.57 0.33 — o. 191 0. iuj 0.150
71J2D Bog marl 0.380 0.86 0.21 3.8 0.258 0.184 0.155
7133 Tufaceous bog marl 0.315 4.44 0.15 0.8 0.215 0,181 0.180
7134A Lake marl 0.190 1.21 0.42 — O.lCO 0.175 0.150

Average pore
diameter ( u, )


Surface area
(m /g marl )
0.06 5.2
0.045 n.i
o . 05 11.0
0.07 8.5
Q.OU3 12.7
7135
7137
7138
7139
7140
7 141
7142
7143A
7144A
71U5A
7146A
7149A
7149B
7150
7151A
7151B
71510
7152
7155
7157A
7158
7159
7162C
7163A
7163C
7163D
Bog marl
Bog marl
Lake marl
Bog marl
Lake marl
Bog marl
Lake marl
Bog marl
Lake marl
Lake marl
Lake marl
Bo marl

Lake marl

Bog marl

Bog marl
Lake marl
Lake marl
Lake marl
Bog marl
Bog marl

Bog marl

0.571
0.277
0.514
0.522
0.481
0.672
0.550
0.575
0.551
0.625
0.543
0.410
0.581
0.472
0.600
0.573
0.446
0.400
0.420
0.367
0.501
0.622
0.931
0.775
0.591
0.719
1.63
0.17
1.28
1.31
1.34
1.72
1.22
1.68
1.27
1.07
0.69
4.85
2.14
1.30
2.58
1-51
0.78
1.07
2.25
1.38
1.02
1.28
3.1
1-7
2.61
2.44
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
18 —
23 —
27 4.4
37 —
34 2.7
22 —
38 —
18 —
36 —
27 —
26 —
14 2.1
21 —
21 3-9
23 —
33 —
51 —
32 —
15 ~
29 —
26 5.2
33 —
24 6.8
17 • —
19 5-2
15 —
o. 196
0.207
0.211
0.116
0.232
o. 172
o. 189
0.185
0.188
0.261
0.115
0.168
0.135
0.088
0.160
0.193
0.173
0.210
0.258
0.163
o. 191
0.212
0.094
0.119
0.201
0. 140
0.171
0, 188
0.183
0. 153
1.182
0.165
0.176
0.182
0.170
•J.172
0. lit
0.187
0.182
o. 167
0.119
0.170
0.178
0.179
0.165
0.155
0.161
0,147
0.172
0.146
0.139
0.141
o. 115
?
o. 150
0.120
o. 165
0.135
o. 150
0. 150
o. 115
0. 110
0.090
o. 160
o. 115
0. 140
0. 120
0.155
o. 170
o. 160
0. 130
o. 125
0. 120
0. 140
0. 100
0. 110
o. 105
0. 110
0.05
0. 10
0.05
0.035
o.*
0 . 044
0. 044
0.041
0.04
0.011
0.035
0.01
0.037
0.01
0.03
0.01
0.044
0.037
0.037
0.035
0.037
0.045
0.04
0.032
0.035
0.035
13.7
5.3
10.3
13.2
14.3
13.7
12.1
14.3
13.8
12.3
16.2
15.7
14.6
13.4
31.0
14.2
12.2
15.8
13.0
12.5
14.2
11.9
13.6
15.3
11.1
14.0






1
UJ
u>
1
















*Column  4 minus column 1.
                          **Based on CaCO   content of rock sample, assuming
                            no shrinkage of CaCO  grains  on calcination.
"^Calculated from the less  than O.ln
 portion  of the pore volume versus pore
 size  graph.

-------
                                   -  3k -

the calcines in order that direct comparisons "between the calcine data and the
marl data could "be made.  It would not "be correct to compare the calcine data
on a "per g calcine" basis with the marl data on a "per g marl" "basis since, of
course, 1 g of marl produces less than 1 g of calcine, depending in part on the
CaC03 content of the marl.  The calcine pore-volume and surface-area data in
table 6 can easily be converted from "per g marl" to "per g calcine" by
multiplying the values given by 100/[lOO - ($H20 + $CC>2 + %S®3 + $0rg. C)].
These percentages can be found in table 3.

          Pore-volume curves for marls 7132D, 71^9A, 7137, and their calcines
are shown in figures 10, 11, and 12.  The pore-volume curves for marl 7132D
and its calcine  (fig. 10) are typical of those obtained for most of the marl
samples.  The second step on the calcine pore-volume curves (figs. 10 and 11)
is interpreted as resulting from creation of new pores by calcination of the
CaC03 in the marls.  The vertical displacement of the calcine pore-volume
curve for marl 7132D (fig. 10) from the marl pore-volume curve cannot be
attributed to any one factor but is probably due to loss of volatile impurities
on calcination,  opening of any closed pores, and other unknown factors.  The
lack of vertical displacement of the calcine pore-volume curve for marl 71^9A
 (fig. 11) from the marl pore-volume curve can be attributed, in part, to a lower
content of volatile impurities in the marl.  Marl 7137 is a unique sample in
that no fine pores less than O.ly in diameter are seen in the calcine pore-
volume curve  (fig. 12).  On the basis of chalk calcination test results to be
discussed later, it appears that in marl 7137, which contains very fine pores,
calcination results in the enlargement of those pores as opposed to the creation
of new pores.

          The theoretical pore-volume  increase on calcination of pure nonporous
CaC03  (Iceland spar) is simply the result of C02 loss; however, some particle
shrinkage usually occurs on calcination and hence, the actual increase in pore
volume  on calcination  of  CaC03  is  usually less than  the  theoretical increase.
The  amount  of particle shrinkage will depend upon the  harshness  of calcination
conditions, with the limit being a dead-burned nonporous calcine.   The  cal-
cination  conditions used  in the  present  study are fairly mild  and produce  a
porous  calcine.  For typical  samples, which  are  porous and  somewhat impure,
the pore-volume  increase  on calcination and  calcine  pore structure will depend
upon loss of  any volatile impurities present (such  as  moisture)  and C02,  opening
of any  closed pores, and  particle  shrinkage.  Pore-volume  increase can  be  larger
or smaller than  the theoretical  increase based on CaCC>3  content  only.   The
theoretical pore-volume increase due to calcination, assuming  no particle  shrink-
age and based on the CaC03 analyses  (table  3), was  calculated*  and is included
in table 6.   The increase in  pore  volume on  calcination  of  the marls was  computed
from measured data by  two methods.   In the  first method, it was  assumed that the
increase in pore volume was simply the difference between  the  total pore volumes
of the calcined  and uncalcined marl.   In the second method, the  increase in pore
volume was computed from the  second  step of  the  calcine  pore-volume curve.


* 1 g pure CaC03 -KD.56  g CaO.  On'  the basis  of densities of 2.71  g/cc for  CaC03
    and 3.32 g/cc for  CaO, one obtains the theoretical volumes of 0.369  cc/(g of
    CaCOo) and 0.169 cc/(0.56 g  of CaO)  and  hence,  0.200 cc increase in pore
    volume when  1 g of  pure CaC03  is calcined.   For  impure  samples,  the theoret-
    ical pore volume increase per  g  rock is  0.200 x  $CaC03/100.

-------
                         -  35  -
                                   I  I  I    I     | I  I
         Sample no. 7132D

         Sample wt. - 0.2 g
                            Pore d i ameter (u)
Pig.  10 - Pore-volume curves  for l6xl8 mesh particles  of
           bog  marl 7132D  and  its calcine.
         Sample no. 7I49A

         Sample wT. - 0.2 q
                           Pore diameter (u)
Fig.  11  - Pore-volume curves for l6xl8 mesh particles of
           bog marl  714-9A and its calcine.
          Samp I e no. 7137

          Samp 1e wt. - 0.2 a
                            Pore diameter
Fig.  12 - Pore-volume curves  for l6xl8 mesh particles of
           bog marl 7137 and  its calcine.

-------
                                   -  36  -

          The pore-volume increase of the  marls (l6xl8-mesh) on calcination
(at 850° C), computed from total pore volumes, ranges from 0.091* to 0.26l cc/g
marl; in the majority of the samples, the  increase is "between 0.18 and 0.22
cc/g marl.  The pore-volume increase computed from the second step of the
calcine pore-volume curve ranges from 0.09 to 0.180 cc/g marl.  The theoretical
pore-volume increase ranges from 0.1^3 to  0.188 cc/g marl.  A sample-by-sample
comparison of the data in table 6 shows that the pore-volume increase determined
from total pore volumes is usually higher  than the theoretical increase, while
all values calculated from the second step of the calcine pore-volume curves are
slightly lower than the theoretical values.  Thus, the interpretation that the
second step of the calcine pore-volume curves is due to calcination of CaC03 is
correct.  However, it is impossible to say specifically why considerable variations
in the actual pore-volume increase on calcination are obtained.

          Electron micrographs of marls 7151A and 7150 calcined at 850° C are
shown in plate 5A and 5B.  The CaO grains, about 0.2y to 7y in diameter, are
aggregated into particles about 2u to 7u across.  These particles likely were
derived from individual calcite grains (up to 7y) in the original marls.  The
largest pores observed are those existing in the uncalcined marls.  The very
fine pores  (<0.1y in diameter) are within the particles, composed of the very
fine CaO grains.

          The surface areas of the marls are indicative of the fine grains
present in the marls and show that very fine pores do not exist to any appreciable
extent in the marls.  The surface areas of the marl calcines are greater than
those of the marls as a result of the creation of fine pores within the CaCOg
grains by calcination.  Also, surface area and pore volume are created by
removal of  the volatile impurities by calcination.  Presumably some of the
carbon in the organic matter remains in the  calcines and adds surface area
to the calcines.  The surface area,  31.0 m2/g marl, for sample 7151A can be
attributed  only to the sample's high (13.^ percent) organic carbon content.

          Data in table 7 illustrate the  effect of different  calcination condi-
tions on pore structures of calcined l6xl8-mesh marl particles.  With the  ex-
ception of marl 7162C, only small  changes  in the total calcine pore volume are
observed here.  An appreciable fraction of the l6xl8-mesh particles of marl
7162C disintegrated when calcined  at 950°  C, thereby decreasing the total  pore
volume in the calcine.  The pore-volume curves for five different  calcination
conditions are given for marls 7133, 7150, and 7162C in figures 13, lU, and 15-
Simply increasing the calcination  temperature from 850° C to  950°  C has only
a  small effect, if any, on the pore-size  distribution.  The addition of
10 percent carbon dioxide to the nitrogen  gas stream promotes growth of the
CaO grains and a corresponding widening of the fine pores created  during the
calcination process.  Longer calcination times of 60 minutes  under both the
pure nitrogen and the 10 percent carbon dioxide-90 percent nitrogen gas streams
usually resulted in further widening of the  fine pores.  The  large pores existing
in the marl were usually not affected either by raising the calcination tempera-
ture to 950° C or by increasing the  total  calcination time to 60 minutes.

-------
                               - 37 -
Plate 5 - Typical textural features of lime in calcined marl;  A. marl
          sample 7150 (x 10,100), B. marl sample 7151A (x 4400).

-------
                                      -  38 -
          TABLE 7 	 EFFECT OF CALCINATION CONDITIONS ON CALCINE PORE STRUCTURE AND SURFACE
                            AREA OF 16x18 MESH PARTICLES OF MARL
Sample
number
7132D
Calcination
conditions*
(a)
(b)
Calcine
pore volume
(cc/g marl)
0.638
0.646
Pore-volume
change on calcination**
(cc/ g marl )
Average diameter of pores
created ty calcination
U)
Surface area
{ m^ g marl )
0.258 0.05 11.0
0.266 0.06 7-1
7144A (a)
(b)
7145A (a)
(b)
7149A (a)
(b)
7153 (a)
(b)
(o)
(d)
(e)
"150 {a}
(b)
(o>
(d)
(e)
-U62C (a)
(b>
(o)
(d)
(e)
0.742
0.723
0.886
0.755
0.578
0.588
0.560
0.543
0.540
0.529
0.59^
0.560
0.5W+
0.587
0.513
0.523
1.028
0.948
0.892
0.710
0-758
3.188
0.169
0.2cl
0.135
0.168
0.178
0.245
0.228
0.225
0.214
0.279
0.088
0.072
0.115
0.041
0.051
0.094
0.014
-0.042
-0.224
-0.176
0.04
0.04
0.044
0.05
0.04
0.04
0.07
0.08
0.13
0.10
0.30
0.04
0.04
3.08
a. 08
0.20
0.04
0.05
0.13
1

13.8
1 1 L.
12.3
3.7
15.7
12.1
8.5
£; <^
^ .4
4.7
1 . 6
13.4
10.6
4.7
3 . 7
1.8
13. £
9.6
3.3
l.S
1.3
•Calcination conditions are as follows:
   (a) 850°C, about 7 min.,  10Q£ N  stream
   (b) 950°C, about 4 min.,  100)6 K_ stream
   (c) 950°C, 10 min., IQSf COg-gOg ]J2 stream
   (d) 950°C, 60 min., 100# Ng stream
   (e) 950°C, 60 min., iq< C02-9C# Ng stream
                                         **Caleulate(J from calcine pore volume and marl pore volume.
            The effect  of different  calcination  conditions on  the calcine surface
 area of l6xl8-mesh  particles can be seen in table 7-  Calcination at 950°  C  under
 pure nitrogen lowers  the surface areas of the  calcines 10 to Uo percent from
 the values at 850°  C.   Calcination under a 10  percent carbon dioxide-90 percent
 nitrogen gas stream reduces the surface areas  of the calcines even more.   Further
 reduction in the surface areas of  the calcines is observed for calcination times
 of 60 minutes at 950° C under either the pure  nitrogen or the 10 percent carbon
 dioxide-90 percent  nitrogen gas streams.  The  surface area values obtained at
 950° C  were generally between 1.7  and 8.5 m2/g marl and those obtained at  850° C
 were between 8.5 and  16.0 m^/g marl.  However, inspection of these results in
 table 7 shows that  the addition of 10 percent  carbon dioxide to the gas stream
 has a much greater  effect on the surface areas of the calcines than that brought
 about by simply raising the calcination temperature from 850° C to 950° C.

-------
                            -  39  -
                  i  i  i—i	1	r—[—i—i	1	n~
                  10                1                0.1              0.01
                            Pore diameter  (u)
Fig. 13 - Pore-volume curves for l6xl8 mesh particles of tufaceous
          bog marl 7133 (a) and its calcines (b-f).  The calcination
          conditions are:  (b) 850° C, about 7 min.,  100$ N2 stream;
          (c) 950° C, about 4 min., 100$ N2 stream,  (d) 950° C, 10
          min., 10$ C02-90$ N2 stream; (e) 950° C, 60 min., 100$ N2
          stream; (f) 950° C, 60 min., 10$ C02-9Q$ N2 stream.
                             Pore diameter (y)
  Fig.  14  - Pore-volume  curves  for  l6xl8 mesh  particles  of  lake marl
            7150 (a)  and its calcines  (b-f).   The  calcination  con-
            ditions  are:  (b) 850° C, about 7 min..  100$  N2  stream;
            (c)  950° C,  about k min.,  100$ N2  stream,  (d) 95°  c»  10
            min.  10$ C02-90$ N2 stream, (e)  950°  C,  60  min.,  100$
            N, stream, (f) 950° C,  60  min., 10$ C02-90$  Ng  stream.

-------
                                    - ko  -
                                         i  i  i—r
                                                        i i  i—r
              ;i
              T—I—i	1	T~T-I—r

                   Sample no. 7162C

                   Sample wt. - 0.2 g
                                             1 - 1
                                                        i  i i—r
                                    Pore diameter
           Fig. 15 - Pore-voluae curves for 16x18 mesh particles of bog marl 7162C (a) and its calcines (b-f).
                 The calcination conditions are: (b) 850° C, about 7 min. , :00£ K2 stream; (cl 950° C,
                 about "» min., 100* N2 stream; (d) 950° C, 10 min., 10? C02-90jg N2 stream; (e) 950= C,
                 60 min., lOOjJ N2 stream;  (f ) 950° C, 60 nin. , 10£ C02-9C# N2 stream.
lTOx20Q-Mesh Particles

           Table 8 summarizes the data on  170x200-mesh particles  of marls calcined
at 850° C.   Corresponding data for l6xl8-mesh particles have  been included in
table  8.   Direct comparison of data for marls 7133, 7150,  and 7162C shows that
the pore structures  (<0.1y) and surface areas of the calcines are not appreciably
dependent upon particle  size.

           Pore-volume and penetration-volume curves for a  tufaceous marl
(7133,  fig-  16) and  a lake marl (7150, fig.  17) show the close similarity in
shape  in the ^O.ln pore  range for the l6xl8- and 170x200-mesh particles and
their  calcines.  Note that for the 170x200-mesh particle data, both the
penetration-volume and void-volume curves are shewn in figures 16 and 17 to
illustrate the relative  importance of the difference between  pore volume and
penetration volume of these fine-mesh particles.  The penetration-volume curve
for 170x200-mesh particles of tufaceous bog  marl 7133 (fig- 16)  is identical
with the penetration-volume curve of its  calcine in the 2.0u  to  O.ly range, but
the penetration-volume curve for 170x200-mesh particles of the lake marl 7150
(fig.  17) lies below the penetration-volume  curve of its calcine.  However, the

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            TABLE 8 — COMPARISON OF TEST RESULTS ON 16x18 AND 170x200 MESH PARTICLES OF MARL
Sample
number Mesh

Pore
volume
(cc/g)
Average
pore size
(n)

Pore
volume
(cc/g marl)
Pore-volume
increase*
(oc/g marl)
Theoretical
pore volume**
(cc/g marl)

Pore volume
(co/g marl)
T126A I6xl8 0.233 1.65
7126A 170*200 0.150 0.6 0.320 0.170 0.177 0.180
Average pore
diameter (11)
Surface area
(m2/g marl)
O.Ot 13-8
7133
7133
7150
7150
7162C
7162C
16x18
170x200
16x18
170x200
16x18
170x200
0.315
0.070
0.472
0.250
0.934
0.320
U 44
1.0
1.30
0.8
3.1
1.5
0.560
0.230
0.560
0.425
0.878
0.455
0.245
0.170
0. 188
0.175
0.091*
0.135
O.l8k
0.184
0.167
0.167
0.172
0.172
0.180
0.170
0.140
0.155
0.092
0.155
0.07
0.055
0.04
0.045
O.Oi*
0.045
8.5
10.3
13. t
15-1
13.6
13.4
  *Pore volume of calcine minus that of the marl.
 "Based on CaCO, content of rock sample, assuminc no shrinkage of CaCOj grains on calcination.
  ^Calculated from the less than O.V portion of the pore volume versus r°re-size curve.

pore-volume curve for l6xl8-mesh particles of tufaceous bog marl  7133 (fig.  l6)
lies  below the pore-volume curve of its calcine, but the  pore-volume curve for
I6xl8-mesh particles  of lake marl  7150  (fig.  17) is identical with the pore-volume
curve of its  calcine  in the lOOu to O.Uy  range.  It is not clear  at this  time why
these slight  differences between the curves are  observed.  Both figures were
included to  show some of the complexities in interpreting pore-volume and
penetration-volume  data.
                      I	r-n—I     I
                   Sample  no. 7133

                   Sample  wt. - 0.2 g
                                                                              — 0.08
                                                                               -  0.04
                                                                                 o.oo
         100
                                                              o.i
                                                                              o.oi
                                      Pore diameter
         Pig   16 - Pore-volume curves {left ordinate)  for  l6xl8 mesh particles and
                   penetration-volume curves (right ordinate) for 170x200 mesh
                   particles of tufaceous bog marl 7133 and their calcines.
                                                                                     TJ
                                                                                     CD
                                                                                     D
                                                                                     01
                                                                                     -H
                                                                                     0°
                                                                                     <
                                                                                     O
                                                                                     O
                                                                                     O

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    Sample no. 7150

    Sample wt. - 0.2 g
                                                                           0.00
                                                     0.1
                                                                        0.01
                          Pore diameter (y)
Pi«. 17 - Pore-volume curves (left ordinate)  for  l6xl8 mesh  particles
          and penetration-volume curves  (right  ordinate)  for 170x200
          mesh particles of lake marl  7150 and  their calcines.

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                                   - U3 -
                              CHALK INVESTIGATIONS


                  General Characteristics and Origin of Chalks


          Chalk is a variety of fine-grained limestone that is especially
porous, is partly incoherent, and is composed mainly of minute fossil fragments
of coccolithophores.  These unicellular organisms float in marine waters and
secrete CaC03 platelets, called coccoliths, that cover the outer surface of the
organism.  The coccoliths are generally disc- or wheel-shaped and consist of
10 or more tabular crystallites of calcite interlocked to form a particle,
generally k\i to 12y in diameter.  Fragments of coccoliths and other very fine
grained calcite (probably chemically precipitated in marine sea water) make
up the bulk of chalk strata.  Also important, however, are other, larger
fossils, mainly foraminifera and bivalve shell fragments that are scattered
throughout the chalk material.  These are composed of coarse-grained calcite.

          Other minerals in chalks are quartz, various types of clay (mont-
morillonite, for the most part, and lesser amounts of illite), mica, iron oxides,
and pyrite.  Quartz  (Si02) has the form of discrete grains Uy to 62y across;
pyrite  (FeS2) and iron oxide  (magnetite, hematite, and goethite) occur mainly
as 10y to 20y opaque grains.  Clay occurs in flakes less than 2y in size scattered
throughout the very fine grained calcite, and in  some chalks glauconite  (green
pellets of illite clay) is rather abundant.

          Chalks were formed by the settlement of the coccoliths, foraminiferal
tests  (shells), and probably  other crystallites of calcite on the bottom of
shallow to moderately deep seas.  Tributary rivers and streams  carried  into the
sea quartz silt and  clay particles which were deposited  simultaneously  with the
fossil  fragments, mainly along the margins of the sea.   Periodically, tributary
rivers  brought extra heavy loads of clay and silt that form thin  sheets of  shale
within  otherwise uniform beds of chalk.  In cases where  the tributary load was
especially heavy, the resultant rock  is  classified as  a  calcareous  siltstone or
claystone.   It is important  to note here that in  the  geologic  literature of  the
southern  states, these  impure calcareous rocks are frequently classified as marls
but are quite unlike fresh-water lake marls.

          Chalks  sometimes  change  laterally and vertically into limestones,  with
decreasing porosity and increasing hardness of the  carbonate  rock,  and  therefore
some  fairly  dense limestone  and  chalky limestone  strata  occur interbedded with
chalks  in some deposits.


                 Sources and Samples of Chalk  and Chalky Limestone


          Chalk  strata crop out  in the United States  principally in Kansas, Texas,
Arkansas, Mississippi,  and Alabama (fig. 5).   These strata are geologically
related, as  shown in figure 18,* by fact of the similarity of fossil content and
   References for the correlations of the Upper Cretaceous formations are:  Kansas-
     Texas (Reeside, 1932), Texas-Arkansas (Pessagno, 1969), Arkansas-Mississippi
     (Boswell and others, 1965), Mississippi-Alabama (Copeland, 1968); for  the
     correlations of the Oligocene formations: Mississippi-Alabama (Deboo,  1965;.

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   *The Marianna Limestone and  the overlying Suwannee Limestone,  both 01 igocene
     in age, occur in the Florida  panhandle and  are in many places high-purity,
     fine-grained, porous, and chalky limestones (Reves, 1961).
* *The Oca la  Limestone of southeastern Alabama (and southwestern Georgia)  is
     composed of  chalky and porous limestones very  similar in character to the
     Iimestones of the Ocala  in  Florida.
  18 - Geologic time-rock classification of carbonate rocks studied.  The column under each
       state  shows formations  that occur in those parts of the state fron which samples
       were collected.  In these areas formations of other roclc types occur but are not
       shown  here.  Vertical scale does not represent true thickness of rock units or dura-
       tion of time.  A hiatus  represents a period during which either no sediments were
       deposited  or sediments  were eroded prior to deposition of superposed unit.

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                                   - 1*5 -
age relations of the strata that overlie and underlie the chalks.   The  principal
chalk strata are geologically classified as the Niobrara Chalk in  Kansas  and
adjacent states, the Austin Chalk in central and northeastern Texas,  the  Annona
Chalk in Arkansas, and the Seljna Group in the Alabama-Mississippi  area.   Each  of
these units is recognized as part of the rock strata of the Upper  Cretaceous
Series.  The Cretaceous Period, approximately TO million to 135 million years
ago, is the geologic time during which rocks of the Cretaceous System were  deposited.
Some chalks and chalky limestones occur in rocks deposited during  the Tertiary
Period (2 million to TO million years ago).


Niobrara Chalk

          According to Runnels and Dubins (19^9), the purer chalk  strata  of the
Niobrara Chalk occur in the lower part of the formation, designated the Fort Hays
Limestone Member (fig. 18).  The Fort Hays consists of massive beds of  buff to
light gray chalk, 0.5 to T feet thick (average about 2 feet), separated by  0.1
inch thick shale partings and 0.1 to U-inch beds of shaly chalk and/or  bentonite
(montmorillonite clay of volcanic origin).  In Kansas, the thickness  of the Fort
Hays varies from about 30 to 65 feet (Zeller, 1968, p. 5T).  The upper  part of
the Niobrara, the Smoky Hill Chalk Member, consists of interbedded shale  and chalk
as does the lower part, but the upper part is much more shaly in most places.
The Niobrara outcrop belt in Kansas and Nebraska is outlined in figure  5-  The
Niobrara crops out in other areas to the north and west of the area shown—in
eastern South Dakota,* eastern North Dakota, around the Black Hills in  western
South Dakota, and in parts of Wyoming, Colorado, and New Mexico.  Outcrops  of
the Niobrara (and the Greenhorn Limestone) along the Rocky Mountain Front Range,
especially near Lyons, Colorado, provide raw material for cement manufacturing
(Chronic and Chronic, 19T2, p. 101).  Kottlowski (1962) describes  in detail
the deposits of limestones of the Niobrara and other limestone formations in
New Mexico.

          The Fort Hays is quarried by the Ideal Cement Company in Kansas,  near
Superior, Nebraska, and by Hopper Brothers of Weeping Water, Nebraska,  from a
deposit near Nelson, Nebraska.  It was previously quarried for use in construction
of the Cedar Bluff Reservoir dam near Trego Center, Kansas, and for small quan-
tities  of road rock from scattered pits within the area of its outcroppings  in
Kansas.  A detailed study of the occurrence and properties of the Fort Hays in
Kansas can be found in Runnels and Dubins  (19^9)-

          Samples of the Fort Hays were taken from localities designated T208,
T209, T212, T213, and T2lU (fig. 5 and app. 2).


Greenhorn Limestone

          The Greenhorn Limestone contains a considerable thickness of soft and
chalky limestones that were deemed to have value for inclusion in this study.
The Greenhorn occurs below the shale and  sandstone that underlies the Fort Hays
(fig. 18), and it crops out along a band  east of the Fort Hays in Kansas and
elsewhere in the Great Plains states  (Hattin, 19T1)-  Chalky limestone beds in
*D. H. Vice, Burlington Northern, Billings, Montana, reports (personal commun-
   ication) that more than 80 feet of chalk is exposed near Yankton, South
   Dakota; it averages approximately 86 percent

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the Greenhorn are 2 to 10 inches thick and are interbedded with shaly and chalky
limestone beds of similar thicknesses.  Some beds have a nodular structure.   Their
color is either buff or gray, depending on the degree of oxidation of the small
amount of organic matter in the rock.

          The Greenhorn vas sampled at two producing quarries (loc. 7210 and 7211,
fig. 5 and app. 2).


Austin Chalk

          The Austin Chalk crops out in a band roughly 5 miles wide that runs
almost continuously southwest to northeast through central Texas (fig. 5) and
consists predominantly of chalk and some chalky and calcareous claystones.  In
the Austin-Waco, Texas  area, it is about 360 feet thick (Pessagno, 1969, p. 69),
and thick and relatively pure beds of chalk occur, especially near the base.
According to Pessagno (1969), the Austin Chalk near Austin, Texas is divided into,
from the bottom upwards, the Atco Chalk Member, the "Vinson Chalk" Member, the
"Jonah Chalk" Member, the Dessau Chalk Member, the Burditt Marl Member, and the
"Big House Chalk" Member (fig. 18).  The Gober Chalk (Fisher, 1965, p. 63), also
called the Gober Tongue of the Austin Chalk (Stephenson, 1937), occurs in north-
eastern central Texas.  The exact relation between the Gober Chalk and the Dessau
Chalk and Burditt Marl Members is not known, and the position of the Gober shown
in figure 18 is indicative only of its occurrence in the upper part of the Austin
Chalk in northeastern Texas.  With the exception of the Gober, the correlation
between the Texas and Arkansas rock units shown in figure 18 is that of Pessagno
(1969).  Only the Atco, "Jonah," and Dessau Chalk Members and the Gober Chalk of
the Austin were sampled for this study.

          The Atco Chalk Member, as exposed at the sampled localities (7221 near
Waco, Texas, and 7222 about 18 miles southwest of Dallas), comprises ho to 50
feet of buff (upper part) and gray (lower part) chalk, uniformly fine grained,
in massive beds averaging about 1 to 2 feet in thickness separated by paper-thin
breaks of up to 3 inches of thinly laminated chalk.  The basal 1 to 2 feet of the
chalk contains black phosphatic nodules, 1 to 10 mm across, that consist of the
mineral apatite.

          Chalky and nodular limestone beds of the "Jonah Chalk" (Pessagno, 1969)
were sampled over a 9-foot exposure (7220, near Austin, Texas).  Nodules are
abundant in these beds.  They consist of rather dense and hard limestone, and
they are surrounded by soft chalk.  The nodules average about 2 by U inches in
size.

          The Dessau Chalk Member was sampled at one locality (7219, near Austin,
Texas),  where it consisted of very fossiliferous (especially bivalve types)
chalk in beds 2 to 2 1/2 feet thick, separated by 0.5- to 1-foot beds of shaly
chalk.   Some chert nodules and a few nodules of pyrite were observed in the beds
sampled.

-------
                                   - U7 -
          The Gober Chalk was not well exposed at the sampled locality near
Paris, Texas (722*0, a quarry (app. 2) in uniformly fine-grained buff and
gray chalk.  The Go"ber varies in thickness, and in the area sampled it is
thought to be more than 100 feet thick (Stephenson, 1937).


Other Chalk Strata in Texas

          Certain chalk beds in the Pecan Gap Chalk of the Taylor Group (Upper
Cretaceous) that overlie the Austin Chalk in northeastern Texas (fig. 18) have
"been quarried for local agricultural and road rock uses (Fisher, 1965, p. 399).
The upper 2.5 feet of chalk from beds in the Pecan Gap was sampled from an
abandoned quarry at Clarksville, Texas (loc. 7225).

          The Comanche Peak Limestone (Lower Cretaceous) occurs in central
Texas (fig. 18) and contains chalky limestone strata.  A sample was obtained
(loc. 7223) for comparison with samples of the Austin.  The exposure sampled
in the Comanche Peak contained nodular limestone and a small amount of chalk
disseminated around the nodules.


Annona Chalk

          The Annona Chalk  (Upper Cretaceous) occurs in the vicinity of Clarksville,
Texas (Barnes, 1966), and near Foreman and Okay, Arkansas  (Dane, 1929, pi- l).
The areas of outcrop are too small to show in figure 5.  In the localities sampled,
the Annona is 30 to i*5 feet thick and consists of uniformly fine grained chalk in
beds 1 to 10 feet thick.  The fine texture of the chalk is interrupted only by an
occasional large fossil shell.  The beds of chalk are separated by thin partings
of very  slightly laminated  chalk.  Samples of Annona Chalk were obtained from
freshly  exposed faces at two operating quarries  (locations 7226 and  7227).


Saratoga Chalk

          The Saratoga Chalk  (Upper Cretaceous)  crops out  in a rather narrow and
discontinuous band  in southwestern Arkansas from near Saratoga to Arkadelphia
 (Dane, 1929, pi. l).  This  chalk ranges  in thickness from 20 to 60 feet  (Dane,
1929, p. 98) and includes  some  sandy  and glauconitic  (green clay)  chalk  and other
beds that  are clayey chalk.  At the outcrop sampled  (loc.  7228),  it  consisted of
gray chalk with blocky fracture, uniformly  fine  grained except for widely  scattered
fossil shells, and  it was  20  feet thick.  Underlying the  Saratoga beds sampled
were 1 to  2  feet of sandy,  glauconitic,  and phosphatic  chalk,  and below  this was
a considerable thickness  of calcareous  clay of the Marlbrook Marl.


Selma Group

           Chalks  of the  Selma Group (Upper  Cretaceous)  are recognized in north-
 eastern  Mississippi and  northern and  central  Alabama (fig. 5). According  to

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                                   - 1*8 -
Copeland (1968), this group of rock units is comprised of (in ascending order):
the Mooreville Chalk, including the Arcola Limestone Member; the Demopolis Chalk,
including the Bluffport Marl Member at the top of the Demopolis; the Ripley
Formation; and the Prairie Bluff Chalk (fig. 18).  Chalk outcrops of the Selma
Group merge eastward and northwestward into clays and sands that are classified
by other formation names.

          In Alabama the Mooreville Chalk consists of about 300 feet of compact,
very calcareous, locally glauconitic clay and clayey chalk (Copeland, 1972,
p. 2-12).  Because the rocks of the Selma Group dip southward, the outcrop of the
Mooreville lies in the northern part of the outcrop belt (fig. 5)-  The Arcola
Limestone Member averages about 10 feet in thickness and consists of 2 to k beds
of light gray, hard, and fossiliferous limestones, each 6 to 12 inches thick,
interbedded with soft chalk (Copeland, 1972, p. 2-12).  A sample of the chalky
beds was obtained for study (7201*).  The lower part of the Mooreville was not
sampled.

          Most of the purer chalk outcrops of the Selma Group (fig. 5) from
central Alabama to the Tennessee line occur in the Demopolis Chalk.  The out-
cropping chalk is light gray, even textured, and fine grained.  The thickness of
the Demopolis Chalk ranges from U20 to ^95 feet (Copeland, 1972, p. 2-1*0.  In
general, the lower part contains thin beds of clayey chalk, while the middle
part most consistently contains the purer chalk beds.  According to Copeland,
the purer chalk in western Alabama grades upward into 50 to 65 feet of calcareous
clays classified as the Bluffport Marl Member.  Samples 7202 and 7205, both from
Alabama, and sample 7230 from Mississippi were obtained from operating quarries
in the Demopolis Chalk.

          The Ripley Formation, which was not sampled, consists predominantly
of sand, sandstone, and calcareous clay.

          The Prairie Bluff Chalk is the youngest formation of the Selma Group,
and according to Copeland (1972, p. 2-20), it generally consists of sandy and
micaceous chalk; however, he states that the lower kO feet contains a high
percentage of calcium carbonate in Montgomery County, Alabama.  The Prairie Bluff
was sampled at two outcrops near Braggs in Lowndes County, Alabama, where the
chalk is rather typically sandy and has a thickness of 80 feet (iocs. 7206 and
7207).


Tertiary Formations Containing Chalk and Chalky Limestone

          The Tertiary System, the next youngest to the Cretaceous, contains
limestone units important for this study, especially in the southeastern states.
Porous and chalky limestones of the Vicksburg Group (Oligocene) crop out across
central Mississippi (Bicker, 1969), extending eastward into parts of southern
Alabama (Copeland, 1968), and in northern and central Florida (Cooke, 19^5).
The porous limestones in the Vicksburg Group are in the lower part of the Byram
Formation and in the Marianna Limestone.  These formations are quarried for a

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variety of uses at a number of locations in southern Mississippi  (Bicker, 1970,
p. 20), at St. Stephens, Alabama (Copeland, 1968),  and in Jackson County, Florida
(Eeves, 196l, and Maxwell, 1970).

          The outcrop areas of the principal Tertiary limestones  in the southeast
are shown in figure 5.  The area outlined in Mississippi was  taken from Bicker
(1969) and includes the Chickasawhay Limestone (Oligocene), which generally  is
composed of dense limestone strata that overlie the Byram. The outcrop area
shown for the Tertiary limestones  in Alabama includes the Chickasawhay, the
Vicksburg Group, and the Jackson Group (Copeland, 1968, pi. l), which includes
the Ocala Limestone.  In Georgia,  only the Ocala Limestone outcrop areas  are
shown (Georgia Division of Mines,  Mining and Geology, 1939)-   In  Florida, the
outcrop area shown includes the Ocala Group, the Avon Limestone of Eocene age,
and the Oligocene Series (Vernon and Puri, 1965).

          The Vicksburg Group comprises a number of formations and members,
depending on the region.  The principal units of interest are the lowermost  beds
of the Byram Formation, called the Glendon Limestone Member,  and  the  Marianna
Limestone.  Samples of the lower limestone beds of the Byram  were taken from an
outcrop on the north side of Vicksburg (loc. 7229).  The Marianna Limestone
underlies the Byram in Alabama (Copeland, 1968), where in outcrops  it usually
consists of a thick white to cream-colored chalk.  According  to Toulmin and
others (1966), lower beds in the Marianna include glauconitic limestone and
calcareous sand in western Alabama.  A sample of chalk from the Marianna  was
obtained for study from the St. Stephens, Alabama, quarry of  the  Lone Star
Industries, Inc. (loc. 7201).

          The Ocala Group (Eocene in age) in Florida consists of  soft, cream to
white, porous limestones, generally of high calcium content (Puri,  1957)-  It
comprises the Crystal River, Williston, and Inglis Formations, which  crop out
extensively in Florida—in the northwestern part of the peninsula and also  in
the north part of the panhandle in Jackson and Holmes Counties.  In Georgia and
Alabama, porous limestone strata of Eocene age are classified as  Ocala Limestone.
They crop out in southwestern Georgia along an outcrop belt extending from near
Perry (in central Georgia) to the junction of the borders of  Georgia-Alabama
and Florida.  The Ocala is quarried by a number of companies  along  its outcrop
belt in Georgia (Georgia Division of Mines, Mining and Geology, 1939; Georgia
Department of Mines, Mining and Geology, 1968).  The porous limestones of the
Ocala also extend into southern Alabama from the tri-state junction northwestward
to as far as the Tombigbee River (Cooke, 1926).

          A sample of the Crystal River Formation in central Florida was
collected for study  (loc. 7120).


             Characterization of Chalk and Chalky Limestone Samples


Petrographic Description

          Although the  chalk  samples  are made up primarily of very fine grains
of calcite,  some coarse grains do  occur and  it  is useful  to classify these

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                                   - 50 -
types of calcite by name.  Micrite is very fine grained calcite,  of roughly
equidimensional grains ranging in size from about 0.5U to Uy in diameter.   In
thin sections, micrite is dark brown and is the abundant matrix shown in the
micrographs (pi. 6).  Coarse-grained and clear calcite is called sparite or
sparry calcite.  This type of calcite is nearly transparent (more like Iceland
spar) and occurs as crystallites and irregularly shaped grains greater than 10p
in size, and when several grains are clustered together, they are tightly inter-
locked and have relatively straight grain boundaries.  The light or clear areas
in the micrographs shown in plate 6 are sparite.  Petrographic analyses by-
optical and electron microscopy were made of thin sections and other specimens
of the samples.  Observations are listed in table 9-  Transmitted light micrographs
of thin sections of representative chalks at low magnifications are shown in
plate 6.  Scanning electron micrographs of the very fine grained material in the
chalks at high magnifications are shown in plate 7-  Numerous fragments of disc-
shaped coccoliths occur in the micritic calcite in the chalk samples (pi. 7)-
The quantitative determination of the amount of sparry calcite in the chalk
samples was determined by image analysis using a Quantimet (Harvey and Steinmetz,
1971); and the mean percentages determined from UO or more microscopic fields
of view are listed in table 9.  The percentage of micrite in each sample is
about 100 minus the sparite percentage; however, clay constituents and other
impurities also occur in the micrite, and the Quantimet cannot distinguish these
from micrite.

          The proportion of sparry calcite in fairly pure chalks varies from
5 to 21 percent (averages 10$).  The sample from the Mooreville Chalk  (720U)
is unique in that it contains an unusually large number of calcispheres (pi. 6B).
The proportion of sparry calcite in the chalky limestones (table 9) is higher
than in the chalks and accounts for one of the principal petrographic  differences
between the two types.

          The average grain size of the samples was measured from  exceptionally
thin (approximately lOy), polished thin sections of about 200 particles of crushed
sample, each about 1 mm in size (l6xl8 mesh).  The  individual crystallite grains
were detected by the Quantimet in cross-polarized light, and more  than 80 micro-
scopic fields of view were analyzed in each of two  thin sections of each sample.
The mean ratio of the measured values of_area to boundary projection yields  the
mean grain chord length for the sample  (C, table 9).  C reflects the predominance
of the micritic component of  the samples, and for the chalks it ranges from 2p to
3-^y (average 2.7u).  The samples classified as  chalky limestones  have a mean
chord length from 3y to  7«5y  (average U.ly).


Bulk Density and Crushing Characteristics

          Bulk  density measurements were made  on specimen blocks  (3x2x1  cm)  from
each of the samples.  Most samples were homogeneous and  one block  sufficed;
however,  several samples were somewhat  inhomogeneous,  and  from these two  or  three
blocks were prepared.  The blocks were  oven dried,  weighed,  coated with  paraffin,
and again weighed both in air and  immersed in water.   The bulk density was  computed

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                                         - 51  -
A. 7202. Demopolis Chalk (x 200)
B. 7204-. Calcispheres in Arcola
   Limestone Member (x 100)
C. 7212A. Niobrara Chalk (x 50)
D. 7222A. Austin Chalk (x 50)
E. 7227B. Annona Chalk (x 50)
F. 7210A. Pellets (dark) in
   Greenhorn Limestone (x 50)
              Plate  6  -  Texture  of  chalk  and  a  chalky limestone (F), coarse
                        sparite  in  micrite.

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TABLE 9 — PETROGRAPHY ADD BULK DENSITIES OF SAMPLES
Oeologlc formation
and sample number
CHALKS
Marianna Limestone
7201



Demopolis Chalk
7202

7205

7230


Mooreville Chalk
72 <*


Prairie Bluff Chalk
7206

7207


Niobrara Chalk
7208B
7208C
7209
7212A
7213
72WA
7214B
7214C
Austin Chalk
7221A
7221B
7222A
7222B
722t

Main type
of caloite


Mlcrlte




Mlorlte

Mlorlte

Mlorlte



Miorlte



Mlorite

Mlorlte



Mlorlte
.Miorlte
Mlcrlte
Mlorite
Mlcrlte
Mlcrite
Miorlte

Mlorlte
Mlorlte
Mlorite
Miorlte
Miorlte

Sparry
oalolte* ($)


8




7

6

5



30



29.**

16"*



6
7
1U
13
10
6
9
11

13
21
14
20
6

Mean grain
chord length, C
Constituents and their distribution ( y. )


Foramlnifera tests and other coarse crystalline 2.9
sparry fossil fragments moderately packed in
porous mlorite. Iron oxide grains (2011) and
Clay distributed throughout the porous mlcrite.

Foramlnifera tests, other coarsely crystalline 2.1
sparry fossil fragments, and single crystal blades
abundantly scattered throughout. Also scattered 2.1
grains of quartz {20ii~60p,), glauconite pellets, and
Iron oxide (Bu-UQu dla.). Clay is scattered 2.2
throughout the micrite; some of it is faintly
and Irregularly laminated along bedding planes.

Spheres of sparry calclte (calcispheres ) , mostly 3-4
5 Op dla., abundantly and irregularly scattered
in dense micrite.

Bladed mioa and caloite crystals (200u x 10u) and 2.7
a few much larger crystals (some fibrous shells)
of oalclte scattered in mlorite. Also scattered 2.8
grains (80u) of quartz, and scattered pellets (lOOu)
of glauconite, many of them' enclosing iron oxide grains.

Foramlnifera tests and spheres (calcispheres), ~"~
composed of coarsely crystalline sparry oalcite, ,
mostly 50u to IJOu across, scattered throughout
micrite. Scattered grains of quartz (most less 2.0
than 4Qji) and chert (all samples except 721M-A). ^
Opaque Iron oxide grains (10u dia.) scattered In
micrite and transparent iron oxide stringers occur 3 • 4
in patches and in irregular lenses. The chalk is «
microscopically laminated along irregular planes
occur, mainly along certain bedding planes and, to Q
a lesser extent, scattered in micrite.

Foraminifera tests and other coarse sparry calcite 2.8
(mostly lOOu In size); partly scattered and partly
concentrated in thin beds. Rare grains (20y.) of
quartz and feldspar. Iron oxide mostly in scattered 2*5
grains (10^-15ti dla.). Clay, mostly montmorlllonite ^ 4.
(except 7222B), occurs mixed with the micrite, some of
which is laminated. Glauconite in 7224 occurs in 2.7
pellets and altered mica flakes.
Bulk
density
(g/cc)


1.86




1-95

1.79

1.88



2.36



1.91

1.92



—
1.83
1.68
2.02
2.10
2.07
1.87

2.32
2.21
2.04
2.25
2.29

                                                                                                                ro
                                                                                                                i

-------


samp e num
Pecan Gap Chalk
7225

Annona Chalk
722 6A

7227B

Saratoga Chalk
7228





CHALKY LIMESTONES
Crystal River
7120


Cal oosahatchee Marl
7122A



Greenhorn Limestone
721 OA

7210B

7211
Austin Chalk
7219

7220

M«ln typ« parry
0

Miorite 9


Micrite 6

Miorite 7


Micrite 2}t







Micrite • 31



Micrite 1*




Micrite 33
(pellitoidal)
Micrite 2"»
(pellitoidal)
Micrite —

Micrite 30

Micrite 26
Maan grain
chor eng ,
s and their d

Spheres of sparry calcite (calcispheres, 60u), many 2.5
f oramlnlfera tests, and a few fibrous shell fragments

Coarse sparry calclte (many calcispheres, 60^1} and 2,6
foraminifera tests widely scattered throughout
micrite. Clay 	 mainly montmorillonlte, with lesser 3.0
grains of quartz and iron oxide 	 scattered throughout.

Coarse crystalline sparry calclte and a few shell 3.1
fragments (fibrous) scattered throughout the
micrite. Quartz grains, up to 15 Ou in dla..
glauconite pellets, and iron oxide grains
widely scattered. Clay, mainly montmorillonite,
occurs with the micrite.


Variety of coarsely crystalline fossil fragments U,l
and many coarse fibrous (shell) fragments, all
closely packed in micrite. Macroscopically porous.

Abundant thin shell fragments (needle-shaped), many 7.5
gastropod shells, and a few fragments of fibrous
shells surrounded by macroscoplcally porous micrite.
Most pores occur enclosed by shells and are isolated.

Coarsely crystalline fossil fragments (Inoceramus 3.5
shells), calcispheres (150ii to 600u aia.), and
pellets (300J of micrite set In sparry calclte U.l
(grains 20u to lOOu) cement. The coarse fossil
fragments most abundant in certain beds (about 1 cm thick). —

Coarse sparry calcite in fossil fragments including 3.8
Inooeramus shells and also in Irregularly shaped
patches are closely packed in micrite. Rare pellets 3.^
Bulk
'(""/ \
6

2.26


2.25

2.3t


2.89







2.23



2.25




2.32

2.61



2.6H

2.58
                                                                                                                                                                                                U)
                                                                                                                                                                                                 I
                                                                                             of glauconite and grains  of  iron  oxide.
Commanche Peak Limestone
        7225
Coarsely crystalline sparry calcite fossils,
  fibrous oalcite shell fragments, and grains
  of quartz (40ti) scattered throughout micrite.
                                                                  3.5
                                                                                       2.60
Byram
         7229A
                                                                  18
Large fragments of fibrous shells and of other sparry
  fossils are surrounded by micrite and very fine-grained
  sparry calcite (20vi).  Glauconite pellets and quartz
  grains abundantly scattered and in part concentrated
  in Irregular patches.
                                                                                                                                                             3.0
 *Clear transparent grains of calclte ify diameter and larger.
**Includes some mica and quartz in addition to the sparry calcite,
 '''includes some quartz in addition to the sparry calelte.

-------
A. 7201. Marianna Chalk  (x 3500)
                Lis Chalk  (x 4100)
C. 7221A.  Austin Chalk (x 3924)
D. 7227B. Annona Chalk (x 1622)
                  Plate 7 - Texture of micritic  calcite  in  chalk samples.

-------
                                   - 55 -

from these weights by using the standard formula (table 9).   The  mean bulk
density (g/cc) of the chalk samples is 2.07, with a standard deviation  of
0.21.  For the chalky limestones the mean is 2.48, with a standard deviation
of 0.13.  The samples of the Marianna Limestone and the Demopolis and Niobrara
Chalks generally are the least dense chalk (1.68 to 2.10); the samples  of the
Austin, Pecan Gap, Annona, and Saratoga Chalks have higher densities  (2.0U  to
2.3^); and the chalky limestones are characterized by the highest densities
(2.23 to 2.6k).

          An attempt was made to assess the relative ease of pulverization
of the samples by crushing a portion of each with a small laboratory  jaw
crusher, then passing the material through a small laboratory disc pulverizer
and measuring the particle-size distribution of the resultant powder.  The
particle-size distribution was measured by wet-sieving the greater than 53U
fraction and by standard sedimentation methods for the less than  53y  fraction
of the samples.  The particle-size measurements were plotted on logarithmic
paper, and the median particle size was determined (table 10). It is assumed
that the smaller the median particle size, the easier it is to produce  a fine-
grind product.  The data show considerable variation and little consistency
within the geologic units and with other data.  Some of the samples tested
between 5U and 30y, but most gave values near ^5y.  Thus the usefulness of
these particular data in terms of predicting S02 reactivities is  questionable.


Mineral and Chemical Analyses

          The samples were analyzed for their mineral composition, and  the
results are listed in table 11.  The chalk sample from the Marianna Limestone
was unusual in that a small amount (< 1%) of a very fine grained  heulandite
              H0) , a zeolite mineral, is present.
          Quartz in grains less than kO\i and clays, mainly montmorillonite with
lesser amounts of illite in the form of green pellets of glauconite, are the
principal impurities in the chalks.  Traces of feldspar, magnetite, pyrite
grains, and mica flakes occur in most samples.  These noncarbonate mineral
constituents are thought to be inert with respect to absorption of S02-

          Results of chemical analyses are shown in table 12.   The two columns
at the extreme right in table 12 are values calculated from loss-on-ignition
data and from CaO values.  The "CaO in calcine" represents the weight percentage
of the CaO in the sample after being heated to 1000° C.  The loss on ignition
can be figured for each sample by finding the sum of the C02 ,  H20 , organic C ,
and 803 values .


                  Results and Discussion of Pore Structures and
         Surface Areas of Chalks, Chalky Limestones, and Their Calcines


          The volume and size distributions of pores larger than 0.012y  in
diameter and surface areas were determined on the l6xl8-mesh (l to 1.2 mm)

-------
            TABLE 10 — MEDIAN PARTICLE SIZES OF PULVERIZED SAMPLES
                    (Pulverized under identical conditions
                  to indicate relative ease of pulverization)
   Sample
Formation
   Median
particle size
     (n)
         CHALKS
    7201
    7202
    7230
    7206
    7208C

    7209
    7212A
    7213
    7214A
    7214B

    7214C
    7221A
    722 IB
    7222A
    7222B

    7224
    7225
    722 6A
    7227B
    7228
         CHALKY LIMESTONES
   7120
   7210A
   7210B
   7211
   7219
   7220
Marianna
Demopolis
Demopolis
Prairie Bluff
Niobrara

Niobrara
Niobrara
Niobrara
Niobrara
Niobrara

Niobrara
Austin
Austin
Austin
Austin

Austin
Pecan Gap
Annona
Annona
Saratoga
Crystal River
Greenhorn
Greenhorn
Greenhorn
Austin
Austin
     9
    31
     7
    17
    48
    45
    48
    45
    50
    21
    45
     5
    30
    16
    35
    25
    42
    25
     13
     50
     48
     48
     48
particle-size  fraction of the samples  and their calcines.   The results are given
in table 13.   Calcine pore volumes  and surface areas were  determined on calcined
rock samples,  "but the values in table  13 were reported per gram of rock used to
prepare the calcines in order that  direct comparisons "between the calcine and
rock data could be made.  The calcine  data in table 13 can easily be converted
from grams of  rock to grams of calcine by multiplying the  values given by
100/[lOO-(#H20 + JCC02 + 55S03 + %Qrg. C)].  The percentages are found in table 12.
The theoretical pore-volume increase upon calcination of each sample, assuming
no particle shrinkage and based on  the CaC03 analyses (table 12), was calculated
(equal to 0.20 times the #CaC03/100) and is included in table 13.

-------
                                                 -  57 -
                    TABLE  11 — MINERAL ANALYSES  OF CHALK AND  CHALKY LIMESTONES*
Sample
number
7120f
7122A
7201


7202


72W


7205


7206

7207


7208B


72080


7209


7210A*


721 OB*
7211
7212A



7212B
7213

721^A



7211B

Calcite
(#)
99
72
90


73


95


72


54

5^


82


90


90


93


91
86
93



45
94

96



95

Quartz
nil
XX
nil


X


X


X


XXX

XX


X
(some chert)

X
( some chert )

X
( chert )

X


X
X
X
(chert)


XX
(chert)
X
( chert )
X



X
( chert )
Clay**
M I K
nil nil nil
nil nil nil
XX X nil
(gl)

XX X XX
(gl)

XX X XX


XX XX XX
(gl)

X XX XX
(gl)
XX XX XX
(gl)

XX X XX


XXX


XXX


XXX


XX X X
XX X X
nil X X



X X XX
XXX

XXX



nil X X

Other
minerals
nil
nil
heulandite-X
pyrite-X
mica-X
feldspar-X
mica-X
pyrite-X
mica-X
garnet-X
hornblende? -X
feldspar-X
mica-X
magnet ite-X
mica-X
magnetite-X
mica-X
magnetite-X
garnet-X
feldspar-X
limonite-X
pyrite-X
feldspar-X
pyrite-X
limonite-X
feldspar-X
pyrite-X
limonite-X
feldspar-X
biotite-X
magnetite-X
feldspar-X
feldspar-X
feldspar-X
limonite-X
magnetite-X
mica-X

feldspar-X
limonite-X
feldspar-X
limonite-X
mica-X
magnetite-X
feldspar-X
limonite-X
HC1
residue^
(£)
nil
27.0
8O
• \J


23.8


2.46


26.12


40.4

40.54


16.29


7-25


9.72


5.50


7.68
12.3
5.36



49.3
5-85

2.13



3.48

                                                                              magnetite-X
 •Relative abundance:  XXX equals > 20j6; XX equals \% to 20#;  X equals  <  \%; 	 indicates not determined.
**Clay mineral  species present:  M - montmorillonite; I - illite and/or muscovite-type mica, gl - part  of
     the  illite is  glauconite type; K - kaolinite.
 tConsists of quartz and  clay plus organic matter, feldspar, mica pyrite, and/or other silicates, if present.
 ^Designates  chalky limestones.
                                          (Table  continued on p. 58)

-------
                                                   -  58  -
                                            TABLE  11 —  Continued
Sample
number
7214C


7219


7220*

722 1A

722 IB

7222A

7222B

7223*

7224


7225


722 6A
7227B



7228


7229A*
722 9C*


722 9Df

7229E*


7229F*
7230



Calcite
(*)
92


92


94

86

86

87

86

91

85


75


82
89



71


83
90


68

90


50
80



Clay**
Quartz H IK
X nil X XX


X XX X nil
(some chert) (gl)

X XX X nil
(gl)
X XX X nil

nil XX nil nil

X XX X X
( chert )
X nil X X
(some chert) (gl)
X X nil X
(some chert)
X XX X X
(some chert) (gl)

XX XXX
(gl)

X XX X X
X XX X X
(gl)


XX XX XX X
(gl)

xx — — —
X XX X X
(gl)

X XX X X
(gl)
X XX X X
(gl)

xxx — — 	
X XXX
(some chert) (gl )


Other
minerals
feldspar-X
pyrite-X
limonite-X
feldspar-X
limonite-X
magneti-te-X
magnetite-X
limonite-X
feldspar-X
limonite-X
feldspar-X
magnetite-X
feldspar-X
limonite-X
feldspar-X
magnetite-X
limonite-X

magnetite-X
limonite-X
mica-X
feldspar-XX
magnetite-X
limonite-X
feldspar-X
feldspar-X
limonite-X
mica-X
pyrite-X
feldspar-X
magnetite-X
limonite-X
	
pyrite-X
feldspar-X
magnetite-X
aragonite(?)-X
mica-X
pyrite-X
feldspar-X
mica-X
aragonite-X
feldspar-X
mica-X
limonite-X
magnetite-X
HC1
residue^"
6.17


6.88


5.13

12.0

11-97

12.39

13.30

7.87

11-79


22.01


14.68
9-43



24.76


	
10.5


29-2

7-9


	
18.38



 •Relative abundance:   XXX equals  > 20#; XX equals  \%  to 20#; X equals < \%; 	 indicates not determined.
**Clay mineral species present:  M - montmorillonite;  I -  illite and/or muscovite-type mica, gl - part of
     the illite is glauconite type;  K - kaolinite.
 tConsists of quartz and clay plus organic matter,  feldspar, mica pyrite, and/or other silicates, if present.
 ^Designates chalky limestones.

-------
                                                  TABLE 12 — CHEMICAL ANALYSES  OF  CHALKS AND CHALKY LIMESTONES
                                           (Analyses by Analytical Chemistry  Section,  Illinois State Geological Survey)
Sample
number
7120*
7122A*
7201
7202
7204
7205
7206
7207
72080
7209
7210A*
721 OB*
7211
7212A
7213
7214A
7214B
72140
7219*
7220*
7221A
7221B
7222A
7222B
7223*
7224
7225
7226A
7227B
7228
7230
sio2
nil
0.77
6.48
14.2
1.93
14.2
17.6
25-9
4.83
5.26
3.61
3.42
6.35
3.00
1.93
0.88
2.44
3.78
3.81
2.94
7-63
6.63
6.01
6.62
7.40
7.69
18.1
9.83
5.46
19.6
9.95
A12°3
nil
nil
1.79
5.26
0.26
5.34
7.19
7-35
1.91*
1.27
0.56
1.42
1.53
0.54
1.19
0.03
0.06
1.14
0.54
1.00
1.42
1.29
2.61 •
1.71
1.05
2.27
2.43
2.85
1.37
2.42
4.04
P«2°3
0.42
0.40
0.74
1.98
0.30
2.44
3.26
3.61
0.98
1.32
0.34
0.37
0.68
0.66
0.41
0.37
0.79
1.07
0.59
0.50
0.86
1.02
1.03
1.27
0.44
1.26
0.76
0.83
0.62
1.16
1.28
MgO
0.01
0.91
2.04
0.82
0.14
0.46
1.00
O.Sl
0.16
0.23
0.08
0.12
0.15
0.16
0.27
nil
0.33
0,61
0.22
0.57
0.23
0.33
0.06
0.31
0.44
0.02
0.17
0.27
0.23
0.60
0.46
CaO
55-5
53.0
47.30
39.63
53.45
40.38
29.52
29.71
50.35
50.54
52.23
50.37
47.95
52.28
51.90
53.91
52.58
50.79
51.84
51.82
48.20
48.20
48.41
47-93
49.21
47.84
41.83
45.64
49.01
39.22
44.85
Na20
0.01
0.08
0.08
0.14
0.03
0.14
0.15
0.15
0.07
0.05
0.13
0.10
0.11
0.06
0.05
0.03
0.05
0,08
0.07
0.06
0.06
0.09
0.07
0.09
0.03
0.06
0.12
0.08
0.07
0.14
0.11
K20
0.09
0.02
0.17
0.67
0.08
0.63
1.36
1.36
0.29
0.31
0.17
0.13
0.29
0.23
0.34
0.15
0.16
0.24
0.33
0.15
0.24
0.34
0.49
0.53
0.11
0.33
0.76
0.56
0.31
0.66
0.73
H20
0.08
0.86
0.69
1.22
0.36
1.71
1.91
2.20
0.66
0.72
0.59
0.68
1.11
0.36
0.55
0.33
. 0.31
0.44
0.75
0.72
1.64
1.06
1.03
0.82
0.53
1.04
1.16
1.64
0.92
1.34
1.44
C02
43.61
42.44
39.47
31.97
41.97
30.80
23.96
23.89
39.59
38.92
40.93
39.96
37.65
41.15
41.23
41.10
41.79
40.50
40.27
41.15
37.78
38.22
38.12
37-95
40.20
37.58
32.98
36.04
39.08
31.22
34.21
S°3
0.01
0.09
0.33
1.62
nil
0.74
1.28
1.23
nil
nil
0.03
0.82
nil
nil
nil
nil
nil
0.08
0.14
0.11
nil
1.03
nil
1.1?
nil
0.14
' 0.26
0.31
0.18
0.11
0.64
Organic
carbon
nil
0.14
nil
0.67
0.17
0.77
0.43
0.47
nil
0.10
0.09
1.75
0.19
0.05
0.07
0.41
0.04
0.04
0.07
nil
0.09
0.39
0.12
0.20
0.03
0.11
0.27
0.26
0.18
0.20
0.43
CaO In
calcine
98.6
93.7
79.0
59.2
92.7
60.4
40.1
40.6
84.3
83.7
89.4
87.4
78.6
89.8
88.6
93.6
90.6
86.0
87.5
88.1
78.6
78.7
79-4
77-9
83.1
78.0
63.4
62.4
81.2
58.1
69.5
CaCO,
99.1
94.6
84.5
70.8
95- 1
72.1
52.7
53.0
89.9
90.2
93.3
89.9
85.6
93.4
92.7
96.3
93.9
90.7
92.6
92.5
86.1
86.1
86.4
85.6
87.9
85.4
74.7
81.5
87.5
70.0
80.1












1
VI
MD
1
















^Designates chalky limestones.

-------
TABU 13 — PORE STRUCTURES AND SURFACE AREAS  OF CHALKS, CHALKY LIMESTONES, AND THEIR CALCINES
1

Pore Mi
Oeologic formation volxime por
and aejiplc number (oo/g rook) {
CHALKS
Marianna Limestone
tOCK

»an Surface • Pore
i slse area volume
n ) (m2/g rook) (eo/g rock)


7801 0.302 0.76 8.3 0.128
Demopolli Chalk

7202 0.212 0.15 17-6 0-352
7205 ' 0.232 0.13 	 0.353
7230 0.179
Moorevllla Chalk
7201 0.115
Prairie Bluff Chalk
7206 0.115
7207 0.163
Nlobrara Chalk
7208B 0.202
72080 0.216
7209 0.212
721ZA 0.217
7213 0.183
7211A 0.186
7211B 0.192
72110 0.221
Auatln Chalk
7221A 0.132
7J21B 0.131
7822* 0.11}
7222B 0.152
7221 0.133
Peoan Oap Chalk
7225 . 0.118
Annona Chalk
7226A 0.118
7227B 0.121
Saratoga Ohalk
7228 0.111
CHALKY LIME3TOHE3
Cryatal River Llmeatone
7120 0.086
Calooaahatohee Marl
7122A 0.013
Oreenhorn Limestone
721 OA 0.092
7210B 0.107
7211 0.115
Austin Chalk
7219 0.061
7220 0.062
Coaanohe Peak Limestone
7223 0.171
»Por« volume or calcine minus that of the rock. "Baaed on
0.15 20.1 0.329

0.13 3.1 0.295

0.1? l8.7 O.Z38
0.18 — 0.238

0.25 	 0.315
0.35 7.0 0.355
0.10 7-6 0.388
0.39 	 0.373
0,17 »-7 0.399
0.19 3.2 0.365
0.17 1.1 0.362
o.io — 0.398

0.20 10.8 0.292
0.18 	 0.295
0,18 lO.t 0.302
0.18 	 0.305
0,18 9.6 0.301
0.12 11.1 0.272
0.12 12.8 0.283
0.20 8.0 0.299
0.18 16.0 0.212

0.50 0.5 0.259
0.21 	 0.258
0.51 	 0.292
0.21 1.1 0-297
0.37 	 0-305
0.31 	 0.251
0.18 5.2 0.211
0.15 5.7 0.252
CALCINE
Observed
pore-volune
increase*
(oo/g rook)


0,126

0.110
0.121
0.150

0.180

•0.093
0.075

0.113
0.139
0.116
0.156
0.216
0.179
0.170
0.158

0.160
0.161
0.159
0.153
0.168
0.151
0.165
0.178
0.131

0.173
0.215
0,200
0.190
0.190
0.190
0.182
0.181

Theoretical
pore-volume
increase**
too/g rock)


0.169

0.112
0.111
0.160

0.181

0.105
0.106

.0.161
0.180
0,180
0.187
0.185
0.193
0.188
0.181

0.172
0.172
0.173
0.171
0.171
0.119
0.163
0.175
0.110

0,200
0.189
0.186
0.180
0.171
0.185
0.185
0.176


Surface
area
(»Vg rook)


11.1

8.7
9.1
7.1

11.3

8.5
6.3

9-9
9.2
9.7
8.8
9.6
6.6
9.2
7.7

10.3
8.6
8.0
6-9
7.0
6.7
7.6
6.1
10.0

11.9
2.9
10.1
10.2
8.8
8.2
9.3
9.1
CaC03 content of sample, assuming no shrinkage of CaCOj grains during calcination.
                                                                                                                                              ON
                                                                                                                                              o

-------
                                   - 61 -
          Characteristic textural features of calcined micritic  type  of  calcite
in selected chalk samples are shown in plate 8.   Upon calcination (conditions
specified above), the sparry calcite grains in Inoceramus shells retain  their
original coarse fibrous shape (pi. 9A), but the lime grains are  partly sintered
to give a spongy texture (pi. 9B).  In the main, the calcination of micritic
calcite grains yields porous clusters of lime grains (A in pi. 9C).  However,
the calcination of coccoliths, observed in several specimens, appears to produce
a less porous lime (pi. 9D).

          Comparison of the surface areas of the rocks and their calcines shows .
that some rocks gained surface area and others lost surface area on calcination.
If the calcination process only enlarged existing rock pores, the surface area
of the calcine would be lower than the surface area of the rock.  The size of
the existing pores and the amount that they are enlarged will determine  the
amount of surface area lost.  New pores created in the rock by calcination will
add surface area to the calcine.  The size of the new pores will determine how
much surface area will be added to the calcine.  The opening of  closed pores in
the rock on calcination will also add surface area to the calcine.  Therefore,
a large loss of surface area  on calcination shows that enlargement of pores
predominates over creation of new pores and conversely, a large  surface  area
gain on calcination shows that creation of very fine pores predominates  over
enlargement of existing pores.  However, for many rock samples,  both pore
enlargement and the creation of new pores occur on calcination,  and it is im-
possible to separate their contributions to the total calcine surface area.

          Calcine pore-volume curves usually exhibit two steps,  as seen in
figures 19-2U.  The first step results from unaltered and enlarged pores; and
the second step results from new pores, but it could include enlarged pores if
they were in the same size range as the new pores.


Chalks

          Comparison of the pore volumes and other properties of the chalks
permits the following general observations:  For the chalks that contain more
than TO percent CaCC>3, a good correlation (linear correlation coefficient of
0.88) was observed between the bulk density and the total pore volume as measured
by mercury porosimetry.  This correlation is indicative of a high  degree of
permeability, a characteristic that is important in gas-solid interactions.
Upon calcination at 850° C under dynamic gas flow conditions, a significant
correlation was observed of increasing pore volume of calcined chalk with in-
creasing pore volume of the original chalk  (linear correlation coefficient of
0.953).  With few exceptions, chalks showed a slightly less than theoretical
increase in pore volumes after the calcination process was complete.  No
correlation was observed between the mean pore sizes and the pore  volumes of
the chalks.

          The sample of chalk from the Marianna Limestone, 7201, has the largest
pore volume (0.302 cc/g) and the largest mean pore diameter  (0.76y) of all the

-------
                                          - 62  -
A. 7201. Calcine (x 2809)
B. 7202. Calcine (x 3270)
C. 7221A.  Calcine (x 17,3^0)
D. 7227B. Calcine  (x 1912)
         Plate 8 - Texture  of  calcined  (lime)  samples  of chalks  shown  in plate 7-

-------
                                        - 63 -
A. 7220.  Calcine of sparry
   caloite (x 510)
B. 7220. Close up of (A)
   (x 10,670)
 C. 7208C. Porous aggregate (A) and
   clay  (C)  (x  8200)
D.  7208C. Calcine of coccolith
    (x  8230)
      Plate  9  -  Texture  of  the calcine (lime) from three types of calcite in chalks.

-------
                                   - 6U -
chalks tested.  The pore-volume curves for 7201  and its  calcine are  shown in
figure 19-  Although this sample is not of high  purity (8^.5$  CaCO^),  the
uniformly fine pores created during calcination  (mean size of  0.035U,  fig«  19)
and the corresponding large surface area  (l^.l m2/g rock)  suggest  that this
material should be highly reactive and absorptive  for S02.

          In table 5, distinct differences can be  seen among the samples  studied
from the three chalk formations within the Selma Group (Demopolis, Mooreville,
and Prairie Bluff).  The large surface areas of  the samples of the Demopolis
and Prairie Bluff strongly indicate the presence of abundant pores less than
0.012u in diameter.  These extremely small pores are not measurable  with  a
15,000 psi mercury porosimeter and are not resolved on the electron  micrograph
of the chalk shown in plate 2B.  Pore-volume curves typical for the  Selma Group
samples and their calcines are shown in figure 20
-------
                                      - 65 -
     o.i2 i—i—r
     O.O8 -
     0.04
   o ooo
   o
   Q)
   e
   o
     O.O8
   o
   CL
     O.O4
   o
     O.OO
     O.O8
     O.O4
   Sample no. 7206

   Sample wt. - 0.3 g
   Sample no. 7204

   Sample wt. - 0.3 g
   Sample no. 7230

—  Sample wt. - 0.3 g
     0.00 L-,
        100
                      i	r
                                                                      Calcine
                          10
                                                    O.I
                                   Pore diameter (u
                                                             Calcine
                                                                       :OlK
                                                                      Calcine
                                                                     o.oi
     Pig.  20 -  Pore-volume curves for samples of  the Selma Group  and their calcines:
               Prairie Bluff Chalk  (7206), Arcola Limestone Member  of the Mooreville
               Chalk (72C4), Demopolis Chalk (7230).
3.1 to  11.3 m2/g.   Therefore, most  of the porosity created by calcination must
have resulted from the formation of new pores  rather than from the  enlargement
of existing pores.  This  is inferred from the  pore-volume curves for 720*4- shown
in figure 20.

-------
                                   - 66 -
          The average pore volume for all the samples of the Niobrara is
 0.21  cc/g, and their average mean pure size is O.UOu.  The surface areas of all
 the Niobrara samples increased on calcination.  The pore-volume curves for
 samples 7209 and 72lUA and their calcines (fig. 21) are typical of those obtained
 from  most of the Niobrara samples.  They show that in addition to the creation
 of many new pores within the micrite and sparite grains some enlargement of
 existing pores occurs on calcination.  The pore-volume curves for sample 7213
 and its calcine also are shown in figure 21.  The pore-volume increase on cal-
 cination of sample 7213 is 0.216 cc/g rock whereas the theoretical pore-volume
 increase is 0.185 cc/g rock.  This difference indicates that closed pores
 existed in the chalk and were opened up on calcination.  This opening occurred
 in addition to the enlargement of existing pores and the creation of new pores.
 The opening up of previously closed pores is shown by the vertical displacement
 of the calcine pore-volume curve for sample 7213 in figure 21.  The pore-volume
 curves for sample 7208C and its calcine (fig. 21) are distinctive in that no
 detectable enlargement of existing pores appeared after calcination.

          The average pore volume of the chalk samples from the Austin is
 0.1^  cc/g, and their average mean pore size is O.lSUy.  Both values are measurably
 smaller than those of the Niobrara samples.  The surface areas of the Austin
 chalks are intermediate between those of the Demopolis and the Niobrara.  Pore-
 volume curves for Austin samples 7221A and 7222B and their calcines are shown in
 figure 22.  The surface areas of the calcines are lower than those of the chalks
 (table 5)» and hence, on calcination, enlargement of existing pores predominates
 over  the creation of new pores in these chalks.  The fine pore structure of
 calcined 7221A is shown in plate 8C.

          The pore-volume curves for sample 7225 (Pecan Gap) and its calcine are
 shown in figure 22.  The calcine of this sample has the smallest mean pore size
 of all the calcined samples and there is no dominant mode of pore size below O.lu.

          The pore-volume curves for Annona samples 7226A and 7227B, Saratoga
 sample 7228, and their calcines are shown in figure 23.  All of these samples
 lost  surface area on calcination.  The pore-volume curves show that both enlarge-
ment  of existing pores and creation of new pores occurred on calcination.


Chalky Limestones

          Samples classified as chalky limestones (table 9) are those that have
 low porosity (bulk density > 2.20 g/cc or pore volume < 0.10 cc/g [table 5]) or
have  porosities slightly higher than these criteria but in combination with a
large average grain size (mean chord length > 3u).  We include the results of
tests of these samples even though they are not true chalks, because several
possess properties very similar to those of chalks and may have high potential
use for SOg control in certain areas of the country.

          The results of pore-volume tests of these samples and their calcines
are given in table 13.  Two of the samples of the Greenhorn Limestone and the
 sample of the Comanche Peak Limestone have relatively high pore volumes.  In
nearly every case, the observed increase in pore volume on calcination is greater
than the theoretical increase, an indication that these samples, as opposed to
most  of the chalks, have some completely closed pores or pore openings smaller

-------
                                    - 67  -
  0.12 —
  O.O8
  0.04
  O.OO
o
o
  O.OO
   0.12
  0:08
  O.O4
  O.OO
   0.12
  O.O8
  OJ04
         -I - 1 - 1
                         -i—i	1	r
          Sample no. 7208C



          Samp I e wt . - 0 . 3 a
         -,	.	.	[—r—r





          Sample no. 7213



          Sample wt. -  0.3  g
       -i—i	1	r
                                            -I—i	1	r
           Sample  no.  7209



           Samp Ie  wt.  - 0.3 g
T	1	1	1	1	T





 Sample no. 7214A



 Sample wt. - 0.3 g
                                     -i	1—i—I	1	r
  O.OO '—i—i	r


     IOO
                -I—I	1      I
                        IO
                                                  ~T

                                                   O.I
                                   Pore diameter (u)
                                                           Colcine
                                                            Calcine
                                                                     0.01
    Pig.  21 - Pore-volume  curves for samples  of the Ft.  Hays Limestone

               Member of  the Niobrara Chalk  and their  calcines.

-------
                                       -  68 -
   O.I2
   0.08
   O.04
U
U

-------
                                      - 69 -
      0.12 I—|—i	r
     0.08 -
     0.04
     O.OO
   u
   o
CD
E
3
"5  0.08

CD
     0.04
     0.00
     O.08
     O.O4
     0.00
                            i — i - 1
          Sample  no.  7226A

          Sample  wt.  - 0.3  g
             Sample  no. 7227B

             Sample  wt. - 0.3 g
          Sample no. 7228

          Sample wt. - 0.3 g
        100
                                                                      Calcine
                                                                      Calcine
                                                                      Calcine
                                                             O.I
                                                                               O.OI
                                     Pore  diameter  (y)
       Fig. 23 - Pore-volume curves for samples of the Annona Chalk (J226A. and 7227B),
                the Saratoga Chalk (7228), and their calcines.

than  0.012y that  are opened up during calcination.  The surface areas of the
chalky limestones are less  than 6 m2/g for those tested.

           The  pore-volume curves shown on figure 2h for typical chalky limestones
and their calcines are similar to those obtained for chalks and their calcines.

-------
                                      - TO -
     O.I2
     O.O8
     O.04
     O.OO
     O.O8
  Q)
  E
  13
   o
   Q.
   0)
   >  O.O4
   (D

   e
  0  0.00
     o.oe
    O.O4
    0.00
Sample no. 7120

Samp Ie wt. - 0.3 g
Sample no.  7219

Sample wt.  - 0.3  g
 Sample  no. 7210B

 Sample  wt. - 0.3 g
       100
                         I
                         10
                                                                     1     I
                                                                    Calcine
                                                                    Calcine
                                                                    Calcine
                                                                              O.OI
                                   Pore d iameter (y)
     Pig. 24 - Pore-volume curves  for samples of chalky limestones and their calcines:
              Crystal River Formation (7120), Dessau Member, Austin Chalk (7219), Green-
              horn Limestone (7210B).

The  calcine of sample 7120 has pores predominantly  in the size range of 0.0%
to 0.06y.   Little  enlargement  of pores  previously existing  in  the stone was
observed.   The other type of calcine pore structure  is that  shown by sample
T210B  (fig. 2l|).   In this sample, a bimodal pore-size distribution in the calcine
is observed—a large number  of pores have a diameter of about  O.O^y and a second

-------
                                   - 71 -
pore-size mode occurs at about 0.6y.  In this sample,  a considerable  enlargement
of limestone pores, together with the opening up of isolated limestone pores,
occurred in the size  range from O.ly to ly.   The pore structure  and  behavior
of sample 7219 is intermediate between that of the other two samples  illustrated
in figure 2^.

          The surface areas of the calcines of chalky  limestones  have a wide
range, 2.9 to 1*1.9 m2/g rock.  In each sample measured, a large increase  in
surface area was observed on calcination.  This increase also reflects the
existence of isolated or closed pores in the limestone material.
               SHELL, COQUINA, CALICHE, AND SLUDGE INVESTIGATIONS


                               Sources of Samples


          The Anastasia Formation (Pleistocene) consists predominantly of sea
shells and coquina and occurs extensively along the east and west coasts of
Florida (DuBar, 1958, p. 38-39).  This formation was sampled on an offshore bar
near Turtle Beach, Florida (7121).  Sample 7121A represents the surface shells
and 7121B the underlying shells, which contain, some sand.  Only the upper
U feet of the Anastasia at Turtle Beach was sampled.

          Certain carbonate rocks occurring in Pleistocene strata of southern
Florida are coquinas (shells partly cemented together) such as those that occur
in the Caloosahatchee Marl (DuBar, 1958).  Two samples of this formation were
collected from the pit of J. Cochran, just west of La Belle, Florida (7122).
In this pit, the lower 5 feet of the quarried stone is coquina that consists of
soft, incoherent carbonate shells partly cemented with fine powdery calcite
(sample 7122B).  The upper 2 feet quarried is a fairly hard chalky limestone
bed containing large pores and small gastropods (sample 7122A).  Other formations
in Florida contain similar carbonate rocks (Vernon, 19^3).

          Another formation that contains abundant shell material, partly
cemented, is the coquina facies of the Yorktown Formation in eastern Virginia
(Coch, 1968).  Fifteen feet of coquina exposed above the water level in the
Lone Star Industries pit at Chuckatuck was sampled in three units and combined
in the laboratory into a composite sample  (7203).  Lone Star Industries processes
the coquina to produce a concentrate of shells for use in the manufacture of
cement.  Sample 7203D was taken from the stockpile of washed and otherwise
processed coquina.

          Shells are dredged from shallow waters at various locations along the
Atlantic and Gulf Coasts.  Two examples of such shell deposits were obtained
from the Radcliff Materials, Inc. of Mobile, Alabama—one of clam shells from
Lake Pontchartrain, Louisiana  (712^),  and  one  of oyster shells from Mobile Bay,
Alabama  (7125).

-------
                                   - 72 -

          Caliche is another type of fine-grained carbonate rock type that is
found in the Ogallala Formation in Kansas, New Mexico, and Texas (Frye and
Leonard, 1959)-  Caliche was sampled at two localities.  In Kansas, caliche was
collected from an outcrop just south of the Cedar Bluff Reservoir dam (7215);
and in Texas, a sample was obtained from an operating quarry (7218) producing
road rock.  Kottlowski (1962) describes occurrences of other types of high-calcium
limestone deposits in New Mexico.

          A very fine grained carbonate (calcite) sludge is a waste product from
the Kraft paper manufacturing process.  The Edwards Paper Company, Port Edwards,
Wisconsin, uses this process, and a sample (7153) was taken from its sludge pile
for inclusion in this study.


                 Characterization of Samples and Their Calcines


          Samples classified as shell are from localities 7121, 712U, 7125, and
7203 (app. 2); these deposits are located along the coast of the Gulf of Mexico
in Florida, Alabama, and Louisiana and on the east coast of Virginia (fig. 5).
Chemical and mineral analyses of the samples are given in table lk.  More than
70 percent (by weight) of the shells in 7121A are bivalves of Chione cancellata
(family Veneridae).  A few bivalve shells belonging to other families also occur.
Less than two percent of the sample consists of gastropod shells.  The shells in
this sample consist mainly of the mineral aragonite.  Sample 7121B, augered from
below 7121A, has types of shells identical to those in 7121A but differs in that
a considerable amount of quartz sand is present.  These samples were obtained from
an offshore bar, and similar shells occur all along this bar.  According to
H. S. Puri (l971j personal communication), they are from the Anastasia Formation
(Pleistocene in age), which is a source of commercial shells elsewhere in Florida.

          Sample 712^ contains shells of clams (Rangia), 3A inch to 1 1/k inches
across, gray, and consisting of aragonite.  Sample 7125 contains gray shells of
oysters (Ostrea) about h inches long and 2 inches wide and composed of calcite.
Both of these samples are from shell beds that are commercially dredged and
processed.

          Microscopic examination reveals that the shells in each of these samples
consist of fibrous crystallites of aragonite or calcite (pi. 10).  In the clam
shells, the fibers are laminated in two or more directions (pi. 10A) and the fibers
in each lamella are nearly parallel to each other.  In Chione, pores O.ly to 0.5y
across occur intermittently along the boundaries of the fibers (pi. 10B), and in
the oyster shells, larger pore channels occur (pi. IOC).  Shells observed in
transmitted polarized light are birefringent, and each fiber has a slightly different
orientation from that of neighboring fibers.

          Samples 7122B (coquina) and 7123 (sandstone) are from the Caloosahatchee
Marl (Pleistocene) and contain abundant gastropods up to U inches long, numerous
bivalves, irregular and cylindrical "worm tubes," and a few other types of cal-
careous fossils and fossil fragments.  Fine-grained calcite and quartz silt occur

-------
                            TABLE 14 — CHEMICAL AND MINERAL ANALYSES OF SHELL AND  OTHER CARBONATE SAMPLES
                             (Analyses by Analytical Chemistry  Section, Illinois  State Geological Survey)
Sample
ROCK TYPE
CHEMICAL ANALYSES
Si02
A1203
Pe203
MgO
CaO
Na20
K20
H20
co2
SOj
MINERAL ANALYSES
Calclte
Aragonite
Quartz
Clay
Other
7121A
Shell
(#)
1.36
0.05
0.06
0.13
53.4
0.60
0.09
0.87
41.96
0.07
(*)«
XX
(95)f
XXX
nil
nil
nil
7 12 IB
Shell
34.3
nil
0.11
nil
35.1*
0.49
nil
nil
28.78
0.11
XX
(63)*
XXX
XX
nil
nil
7122B
Coquina
22.6
0.70
0.36
0.73
40.5
0.25
0.08
1.33
32.53
0.09
XXX
XX
XX
nil
nil
7124
Shell
0.88
nil
0.12
0.10
54.0
0.34
0.03
0.92
42.71
nil
nil
XXX(96)
nil
X
nil
7125
Shell
0.37
0.34
0.49
0.06
53.9
0.41
0.04
0.96
42.50
0.09
XXX(96)
nil
X
X
Mica-X
7203
Coquina
	
	
~
	
I
	
	

XXX
XX(8l) +
XX
XX
(glauconite)
Magnetite-X
Mica-X
7203D
Coquina
7-31
nil
1.55
0.15
49.1
0.43
0.07
0.62
38.78
0.59
XXX
XX(88)f
X
nil
nil
7215
Caliche
33.3
1.73
0.42
0.85
33.6
0.30
0.92
0.60
22.99
0.03
XXX(6l)
nil
XXX
nil
nil
7218
Caliche
38.4
2.32
0.57
1.28
29.2
0.24
0.85
1.65
23.70
0.04
xxx(54)
nil
XXX
(cherty)
X
(llllte)
Peldspar-X
Opal-X
Magnetlte-X
7153
Waste sludge
nil
0.02
0.19
0.52
53.8
0.85
nil
1.76
41.47
0.14
XXX(96)
nil
nil
nil
Organic -X
•Relative abundance: XXX - > 20#. XX • if to 20#, X » < if.
'Value is the  sum of the percentages of calcite and aragonite.

-------
A.  Clam shell from 7121*  ,    20~
                                                 93°'
        C.   Oyster shell  from 7125
                                                   (x 1100)
Plate 10 - Characteristic textural features of shells.

-------
                                   - 75 -
"between the shells.   Less than 3 miles to the northeast (loc.  7123),  the "beds
sampled at 7122 grade laterally into more impure coquina and into quartz-rich
sands containing only a few shells.

          Pore structures and surface areas of the shell and other samples  of
the group and their  calcines are listed in table 15-   The total pore  volumes
of shell samples are characteristically very low; these data show an  average of
0.01^ cc/g.  The pore-volume curves for shell 712^ and its calcine shown  in
figure 25 are similar to those for other shells and their calcines.  The  pore-
volume curve of the  calcined shell 7124 shows a rather narrow distribution  of
pore sizes (fig. 25).  Mean pore sizes of shell calcines are large; they  range
from 1.5y to 2.3y (table 15).

          The coquina and shell samples increased in pore volume on calcination
at 850° C from 0.156 to 0.215 cc/g rock.  Electron micrographs of shell calcines
confirm the absence  of small-diameter pores in the calcines, as shown by
plate 11A.  The CaO  grains, about ly to Hy in diameter, are rounded and partly
fused together.

          A sample of caliche, 7218 (table 15), has a low pore volume and its
calcine has a very low pore volume in comparison with the calcines of other
carbonate rock types because it contains high quantities of quartz sand impurity,
typical of caliche.   The pore structure of sample 7215 was not determined.

          Sample 7153, a carbonate sludge from a paper manufacturing  plant, is
of special interest  because it is a waste product.  The sludge consists of
precipitated calcite (table I1*) with about 4 percent organic matter as the only
impurity.  The sludge consists of particles that are in large measure composed
of single grains, 0.5y to 2.0y across, with only slight grain-to-grain interlock.
The pore volume (l70x200-mesh) for the sample tested was 0.27 cc/g, which probably
included a moderate fraction of intergranular void space.  The sludge had a mean
pore size of 1.5y.  Pore-structure data for the sludge and its calcine are listed
in table 15.  The sample was calcined at 800° C and at 850° C; the penetration-
volume curves for the uncalcined sample and the calcines are shown in figure 26.
The calcined sludge resembles calcined shell in its granular texture.  The CaO
grains, about 0.3y to 2.0y in diameter, are spherical and smooth  (pi. 11B).
Since the pore volumes of the 850° C calcine and the sludge material are nearly
identical, the pores that were formed within single calcite grains during the
early stages of calcination  (800°  C) were very rapidly eliminated by fusion of
the lime to form grains about ly across.

-------
                             TABLE  15  — PORE STRUCTURES OF SHELL AND  OTHER CARBONATE  SAMPLES
                                         AND THEIR CALCINES (16x18 MESH PARTICLES)
Sample
number
7121A
7121B
7124
7125
7122B
7203D
7218
7153(1)*
7153(2>*'t
ROCK
Type
shell
shell
shell
shell
coquina
coquina
caliche
sludge
sludge
Pore
volume
(co/g)
0.006
0.013
0.014
0.023
0.106
0.039
0.039
0.270
0.270

Mean
pore size
(p.)
0.30
0.30
0.15
0.15
0.41
0.56
0.25
0.15
	

Pore Me
volume pore
(cc/g rook) (
0.207 2.
0.221 1.
0.240 1.
0.262 o.
0.235 1.
0.157 ~~
0.270 —
0.415 ~~
CALCINE (850° C)
Observed
an pore-volume
size increase
(i) (cc/g rock)
3 0.201
5 0.207
8 0.217
7 ' 0.156
5 0.196
— 0.118
— 	
— 0.145

Theoretical
pore-volume
increase
(ce/g rook)
0.171
0.165
0.192
0.145
0.168
0.176
0.192
0.192

Surface
2area
(m /g rock)
1.1
1
—5
0.3 °^
1
0.3
2.1
0.5
7.2
0.5
~
*The  particle size of samples 7153(1) and 7153(2) tested was  170x200 mesh.
         at 800° C.

-------
                                     - 77 -
    0.20
    0.16
U
o
o
>
ffl
>
o
     0.04
     0.00
T      I     I  I   I





 Sample no. 7124



 Sample wt. - 0.3 g
                                                                    CaIci ne
        100                 10


                                      Pore diameter  (y)


            Pig. 25  - Pore-volume curves  for l6xl8 mesh particles  of


                       clam shell 712^ and its calcine.
                                                                                 0.01
  o
  o
  o
  0)
  Q_
                  Sample no. 7153



                  Sample wt. - 0.2 g
                                       Pore diameter (y)
                                                                                 0.01
          Fig. 26 - Penetration-volume curves  for 170x200 mesh particles  of car-

                    bonate sludge 7153 and its calcines.

-------
         Plate 11 -  A. Relatively smooth and coarse grains of lime in calcined
                   shell material, 712^ (x 14-500); B. Relatively smooth and fine
                   grains of lime in calcined sludge, 7153 (x I**,250).
                 INVESTIGATION OF CARBONATE ROCKS RELATED TO
                PREVIOUS FLUIDIZED BED DESULFURIZATION TESTS
          Certain  carbonate rocks have been used in pilot plant tests  of  fluidized
bed desulfurization  of flue gases.  In these tests, crushed limestone  or  dolomite
has been added to  the  combustion chamber to react with the S02 that is produced
therein from the fuel.  A number of advantages are associated with this process
and the experiments  are described in detail in reports to the U.S. Environmental
Protection Agency  (Robison et al., 1970; Jonke et al., 1971; Hammons and  Skopp,
1971; and Craig et al. , 1971).  Two advantages of this process are the recovery
of calcined additive composed of lime and the recovery of S02 in a form suitable
for conversion to  elemental sulfur or sulfuric acid.  Favorable results were
obtained from these  pilot plant tests.

-------
                                     -  79 -
          Problems experienced  in these tests  associated with the carbonate rock
additives were excessive attrition of particles  of  certain samples by decrepitation
or breakage during high temperature treatment  and excessive agglomeration of one
sample (sample no. 1690, described below) during the lime regeneration  cycle.
It was deemed useful to conduct petrographic studies of certain samples tested
in the fluidized bed process to assess possible  causes for the high decrepitation
and agglomeration that occurred.
                     Samples  and Their Relative Decrepitation
          The samples selected for study were  supplied by Dr. Dennis  Drehmel,
Control Systems Laboratory, U.  .  Environmental Protection Agency.  The  samples
are listed  in table 16 and their  sources noted by footnote.  Fluidized  bed tests
           TABLE 16 — PETROGRAPHY, PORE STRUCTURES, AND DECREPITATION TEST RESULTS
SAMPLE NUMBER
ROCK TYPE
TYPES OF GALCITE (%}
MEA;; GRAIN CHORD, c (\i)
GRAIN DEFECTS1'
Point
Line
PORE VOLUME (cc/g)
CALCINE
Pore volume (cc'g)
Mean pcre size (\i)
Pore-volume increase
(cc/g rock)
Theoretical increase
(cc/g rock)
Surface area
(m /g rock)
DECREPITATION (%)
a b c
1690 2231 1691
dolomite,
sandy and limestone,
calcitic dolomite dolomitie
raicrite (6) None micrite (90)
sparite (5) sparite (10)*
47 19 4
1678 987 ^07
129 30 15
o.oo84 0.0250 0.0056
0.150 0.210 0.192
0.039 0.051 0.110
0.142 0.185 0.186
0.145 0.182 0.174
13.8 13.9 ^-9
3.67 0.23 0.0
d
2257
limestone ,
fossiliferous
micrite (52)
sparite (48)
10
659
62
0.020
0.200
0.060
0.180
0.182
3.68
•Includes dolomite grains > 10(i diameter.
aMcConville, Inc., Ogdensburg, New York
bC. E. Duff k Sons, Huntsville, Ohio (Tymochtee Dolomite).
°Warren Bros. Road Construction, Syracuse, New York.
Denbighshire, Northern Wales, United Kingdom.
tfiumber in 100 carbonate grains that are > 50u diameter times percentage of >
                                                                grains in sample.

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                                    - 80 -

 of samples 1690 and 2257 gave relatively high attrition rates, whereas  sample  1691
 produced a low attrition rate (Craig et al. ,  1971).   In addition,  the tests  of
 Craig showed excessive agglomeration of sample 1690.   The  relative rate of attri-
 tion of sample 2231 in fluid bed tests  is not known at this  time.

           As the attrition by decrepitation of limestone particles is routinely
 evaluated by glass  manufacturers, the samples were tested  using the  same pro-
 cedure (Bitner,* personal communication). The test measures the relative amount
 of crushed sample that explodes  over the sides of a sample container (long,  thin
 boat) during exposure to 1100° C.  Results of our tests on the samples  studied
 are given in table  l6.  These results are in  agreement with  the results of relative
 attrition in fluidized bed tests (Craig et al., 1971).


                            Characterization of Samples


           The samples received were of  a crushed product from a commercial source.
 Representative splits of the samples were prepared and analyzed as described in
 the first section of this report.   As these samples consist  of a variety of  types
 of particles, it is interpreted  that the types  were derived  from different beds
 or strata within the commercial  quarry.   The  most typical  granular texture of
 each sample is shown photographically in plate  12.  Measurable petrographic  para-
 meters, including relative frequency of line  and point  types  of grain defects
 observed optically  within the carbonate grains  and the  pore-volume data for  the
 samples and their calcines,  are  listed  in table 16.  The pore-volume curves  for
 the rocks are very  much the  same and show little porosity.   The mean pore sizes
 of the calcines range from 0.039y to O.llOy (table l6).  The  pore-volume curves
 for the calcines are shown in figure 27.

           Mineral and chemical analyses  are given in table 17.

           Sample 1690 is  a sandy dolomite.  It  has an  inequigranular mosaic
 texture  (pi.  12A).   About 89  percent  of the particles  (or beds) contain rounded
 grains  of quartz and feldspar sand,  80y  to lOOy across,  that  are abundantly
 scattered among  rhombic  and  irregular grains  (50y to 500y) of dolomite.  The
 dolomite  grains  are  generally tightly interlocked.  Some particles consist of
 micritic  type  of calcite  with scattered  dolomite rhombs.  Other particles consist
 almost  entirely  of  quartz and feldspar  grains.  Others  (5 percent of the particles)
 consist of coarse sparry  calcite.   Several particles contain  clay.

           Sample  2231  is  a medium-grained dolomite.  It has an equigranular mosaic
 texture  (pi. 12B).   Grain shapes  are commonly equidimensional with v-points which
make a tight grain-to-grain interlock.   In most particles the size of the grains
 is fairly  constant, mostly around UOy in diameter; other particles have grains
mostly 20y in diameter.   Some particles are porous and contain rhombic dolomite
grains.   Impurities  are rare  iron-stained grains of quartz and feldspar, mostly
 50y in diameter, and clay, which are especially concentrated in parallel bands
 in certain particles.
  Jay Bitner, Assistant Plant Manager, Ball Corporation, Mundelein, IL.

-------
                                         -  81 -
A. 1690. Quartz (Q), feldspar (P), and
   clay around dolomite grains.
B. 2231. Equigranular and inter-
   locking dolomite
C. 1691. Dolomite (clear) in micritie
   calcite; pyrite (black)
D. 2257. Inequigranular limestone:
   sparry and micritie (dark) calcite
        Plate 12 - Typical textural characteristics of samples  studied related  to
                   fluidized bed desulfurization.   Micrograph A taken in crossed
                   polarized light and the others  in plane polarized light;  all
                   magnified x 165.

-------
                                     - 82 -
   o
   u
   o
   o
   Q.
   0)
   i
   o
      0.04
      002
      000
      OD2
      OJDO
      O.OO
      oxe
     OJDO
        IOO
             Sample no. 2257

             Sample wt. - 0.3 g
Sample no.  1691

Samp Ie wt.  -  0.3 g
Sample no. 2231

Sample wt. - 0.3 g
 Sample no. 1690

 Sample wt. - 0.3 g
                          I
                         to
                                                                            0.01
                                   Pore diameter  (y)
          Pig.  27 - Calcine pore-volume curves for samples studied related to
                   fluidized bed desulfurization.
          Sample 1691 is a fine-grained dolomitic limestone.   It has an
inequigranular texture with scattered needle-shaped sparite (fossil shell and
crinoid fragments) and dolomite rhombs (mostly 25^ across)  densely scattered
through micritic calcite (pi. 12C).   Some particles contain sparitic calcite
in grains up  to lOOy across.  Impurities of magnetite  and pyrite grains  (lO\i
in diameter,  and in larger agglomerates) occur scattered throughout the  sample.
Other impurities of chert (Si(>2)  and clay are restricted to certain particles.

-------
                                      - 83 -
                  TABLE 17 — CHEMICAL AND MINERAL ANALYSES
Sample 1690
CHEMICAL ANALYSES (%)
Si02 21.4
Al 0 0.96
Pe 0 0.58
MgO 14.5
CaO 23.4
Na 0 0.04
2
KgO 0.95
H 0+ 0.62
CO 34.59
S • 1 . 07
MINERAL ANALYSES *(%)
Calcite X (7)
Dolomite XXX (66)
Quartz XX
Feldspar XX
Clay X
Other Magnetite
(All X) Pyrite
HC1 residue 26.0
2231

2.12
0.67
0.54
19.9
27-7
0.06
0.32
1.19
43.52
0.73

nil
XXX (92)
X
nil
XX
Magnetite
7-1
1691 2257

9.0 0.34
0.56 0.14
0.33 0.04
0.71 nil
45.3 53.4
0.04 0.01
0.27 nil
0.75 0.41
38.16 43.48
0.60 0.03

XXX (82) XXX (99)
X (5) nil
XX X
nil X
X X
Magnetite nil
Pyrite
Mica
12.6 0.74
•Relative abundance: XXX = > 20#, XX = 1#  to 20#, X = <  \%

-------
                                   - 8U -
          Sample 2257 is a fossiliferous limestone.  It has an inequigranular
texture  (pi. 12D).  Very coarse fossil fragments and calcispheres, both
consisting of sparitic calcite in grains up to 120y across, occur mixed with
micritic calcite.  The sparry calcite content of the particles varies consider-
ably  (10$ to 75$, average U8$), and micritic calcite makes up the remaining
fraction of the particles.  Very few impurities occur; these are rounded grains,
30y to 60y in diameter, of quartz and feldspar, widely scattered flakes of clay,
and lOy grains of magnetite and/or pyrite.
                              Discussion of Results
          The mineral, chemical, and petrographic properties of the four samples
vary widely.  Impurities are mainly siliceous quartz, clay, and feldspar	the
latter  especially abundant in sample 1690.  The occurrence of abundant feldspar
in 1690 accounts for the agglomeration of regenerated calcine particles of the
dolomite observed by Craig et al. (l97l).  The feldspar in the sample has a (220)
d-spacing of 3.2^1* A, which is characteristic of potassium-bearing feldspar
 (microeline, ideally KalSi30g).  Normally, some sodium and calcium substitute
for potassium in the microcline feldspar structure.  Feldspar begins to fuse at
1100° C. It is used as a flux in the ceramic industry to reduce the eutectic
temperature of silicate mixes in the manufacture of glass (Searle, 1933).  During
the process of regeneration of the calcine, Craig heated the sulfated calcine
particles to 1100° C, and it is at this point that the feldspar, especially the
finer grained feldspar, partly fused and caused the undesirable agglomeration.

          The relative abundance of defects within the carbonate grains (table 16)
appears to correlate well with the observed decrepitation.  The defects in the
two dolomites and the dolomitic limestone (1690, 2231, and l69l) are mainly point
defects. Increases in point defects in these samples correspond to increasing
decrepitation.  Also, the mean chord length (table l6), which corresponds to grain
size, increases as decrepitation increases.  The relatively high decrepitation
observed in limestone 2257 appears to be related to the abundance of line defects
in the  sparry calcite, an abundant component in the limestone (table 16).  The
presence of line defects (cleavage and lamellar twin planes) within the sparry
calcite grains also contributes to fracture propagation through the rock, thereby
reducing the hardness and decreasing the resistance of the rock to attrition
within  fluidized bed systems.


                             SUMMARY AND CONCLUSIONS
                                      Marl
          Many rocks described in geologic literature as marls are not carbonate
rocks, and some have only a very low carbonate content, which would make them
unsuitable for use in S02 control processes.  This is especially true of many

-------
                                   - 85 -
so-called marls of marine origin, which contain some carbonate constituents,
mainly shells and shell fragments, "but consist mostly of quartz and clay minerals.

          Most deposits of marl (the term marl being restricted to incoherent
carbonate-rich sediments of fresh-vater origin) have CaC03 contents between
80 and 90 percent; a few have more than 90 percent.   The main impurities are quartz
silt and organic matter.  The grain (crystallite) size of marls is mostly less
than Uy; however, grains lOy to 25y, especially in tufaceous marls, occur scattered
throughout the marl material.  Dispersion of marls in water yields particles
(polygranular) whose median size varies from 6y to 38y.  These particle sizes are
less than half of those of.three pulverized (2 1/2 hours in a ball mill) limestones
tested.

          The pore volume in marl samples with 85 percent or more calcite varies
from 0.2 to 0.9 cc/g (average 0.5).  Although not as significant as expected, a
correlation was observed of decreasing optimum density (Harvard miniature
compaction test) with increasing pore volume (r  = 0.52).  Upon calcination (at
850° C, for 5 to 10 minutes, and under a high gas flow rate), the pore volume
increased about 0.2 cc/g to an average of 0.7 cc/g of rock.  The marl pore
structure is retained and the fine pores created are, for the most part, less
than O.ly in diameter.  The surface areas of the calcines of marls are generally
between 11 and IT m2/g of marl.  Increasing the calcination temperature to 950° C
has little effect on the calcine pore structure but causes a decrease in the
surface areas of the calcines.  However, calcination at 950° C under a 10 percent
carbon dioxide-90 percent nitrogen gas stream and/or for a calcination time of
60 minutes generally results in an enlargement of the fine pores.  Under these
conditions, a major reduction in the surface areas of the calcines is observed.

          The large pore volumes and fine grain sizes of marls and their calcines
indicate that the marls and their calcines would have high reactivities with S02-
In addition, because of the ease of production (no blasting or crushing) of marl,
together with its high degree of disaggregation when mixed with water (no
grinding), this carbonate material should be given important consideration for
use in limestone scrubbing of flue gases at power plants in areas near marl
deposits.


                           Chalk and Chalky Limestone


          Chalk, being a very porous and very fine grained variety of limestone,
occurs mainly in Upper Cretaceous formations in three different areas in the
central and eastern part of the United States:  the Nebraska-Kansas-Colorado area,
along a southwest-northeast belt across central Texas and extending into
southwestern Arkansas, and along a broad belt across Mississippi and Alabama.
Certain Tertiary formations in the southeastern states also contain chalk and
chalky limestones.  On the basis of laboratory studies and tests of 37 samples
collected from the principal chalk occurrences, the following conclusions can
be drawn.
  Linear correlation coefficient.

-------
                                      - 86 -
          The CaC03 content of chalks, with certain exceptions,  is  85  to  95
percent.  The principal mineral components, other than calcite,  are mont-
morillonite and illite (glauconite) types of clay, quartz silt,  and traces of
magnetite.  Each mineral component is mainly microscopic in grain size.

          Petrographically, the chalks consist of 5 to 30 percent relatively
coarse-grained sparry type calcite that occurs in microscopic fossils  50y to
200u across, which are scattered throughout a matrix of micritic calcite  in
grains 0.5U to % across.  Of this very fine grained calcite, about 10 to 20
percent is recognizable as fragments of coccoliths, and the rest consists of more or
less equal dimensional grains that have relatively few grain-to-grain  contacts.

          The bulk density of the chalks tested ranges from 1.68 to 2.36  g/cc
and averages 2.09 g/cc, corresponding to an average porosity of about  23  percent.
Bulk density measurements can be used with moderate success to predict the total
pore volume of the purer chalks (r = 0.88).

          Standarized pulverization of the chalks and chalky limestone samples
yields different particle-size distributions.  The median particle sizes  for
some samples was between 5n and 30y, but for most samples, it was near l*5u.
No apparent relationship exists between the median particle sizes and the volume
or size of the pores in the samples.  However, the smaller the median particle
size, the less coherent is the sample.  The particle-size distribution in a
pulverized sample is theoretically as important as the volume and size of its
pores in determining the sample reactivity in S02 scrubbing processes.

          The pore volumes of the samples range from O.OU3 to 0.302 cc/g, and
the mean pore sizes range from 0.12y to 0.76y.  Chalk samples from the Marianna
Limestone in Alabama, the Demopolis Chalk in Alabama and Mississippi,  and the
Niobrara Chalk in Kansas and Nebraska are, in general, more porous than those
from other chalk formations.  The surface areas of the chalks range from 3.1 to
20.1 m2/g, and of chalky limestones from 0.56 to 8.8 m2/g.  However,  they vary
most from one formation to another.

          On the basis of the weight of chalk., calcines  (850° C under dynamic
gas flow conditions) of samples of the Demopolis, the Prairie Bluff,  the Austin,
and the Annona Chalks have lower surface areas than do the original chalk materials.
Both the enlargement of existing chalk pores and the creation of new pores  (<0.1u)
within the calcite grains were observed in the calcines.  Calcination of six of
the eight chalky limestones apparently opened enclosed pores in the samples, in
addition to enlarging existing pores and creating new pores.  Chalks, with few
exceptions, showed slightly less than theoretical increase in pore volume after
the calcination process was complete.


                    Shell, Coquina, Caliche, and Waste Sludge


          The pore volumes in shell and coquina, which consists mainly of shell,
range from 0.006 to 0.106 cc/g.  Unweathered shell material  averages 0.01^  cc/g.

-------
                                   - 87 -
As a group, shells have the lowest pore volume.  There is no significant
difference in pore volume "between calcitic and aragonitic shells.  As a
consequence of the low pore volumes of shell, its calcines have low pore
volumes  (0.21 to 0.26 cc/g rock).  The surface areas of shells and coquinas
are very low as are those of their calcines (0.3 to 2.1 m2/g rock).  Therefore,
shell material is considered to have low reactivity with S02, whether used in
the calcined form or as pulverized in a wet scrubbing process.

          Caliche is not recommended for use in desulfurization processes, as
deposits are of low purity — less than 65 percent
          Carbonate waste sludge resembles natural marl in many ways and is
potentially very reactive with SC>2, especially in a wet scrubbing process.
However, calcined sludge undergoes more shrinkage than marl and the grains
of lime that are formed have little or no internal porosity.


                    Conclusions Regarding Carbonates Studied
                  in Relation to Fluidized Bed Desulfurization


          The feldspar grains present in sample 1690 partly fused during
heating to 1100° C in the generation cycle of the fluidized bed tests of
Craig et al. (1971).  The number of intragranular optical defects, both point
and line types , was high in samples that showed high attrition rates in
fluidized bed tests.  These samples also showed a high percentage of decrepita-
tion.  The attrition rate and relative decrepitation also increased in carbonate
rock with the coarseness of their mean grain size.
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-------
                                   - 88 -
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-------
                                   - 89 -

Dittos, H. P., 19715 Methods for the removal of sulfur dioxide  from waste gases:
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Hattin, D.  E. , 1971, Widespread, synchronously deposited, burrow-mottled  limestone
     beds in Greenhorn Limestone (Upper Cretaceous) of Kansas  and southeastern
     Colorado:  Am. Assoc. Petroleum Geologists Bull., v. 55,  no. 3, p. U12-U31.

Jonke, A. A., G. J. Vogel, L. J. Anstasia, R. L. Jarry,  D. Ramaswami , M.  Haas,
     C. B.  Schoffstoll, J. R. Pavlik, G. N. Vargo, and R. Green, 1971, Reduction
     of atmospheric pollution by the application of fluidized  bed combustion:
     Argonne National Laboratory (Argonne, IL) Annual Report ANL/ES-CEN-100U ,
     112 p.
Kansas Geological Survey, 19<5^j Geologic map of Kansas:   Kansas Geol.  Survey
     Map M-l

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                                   -  90 -
Kottlowski, F. E. , 1962, Reconnaissance of commercial high-calcium limestones
     in New Mexico:  New Mexico Bureau of Mines  and Mineral Resources Circ. 60,
     77 p.

Maxwell, E. L., 1970, Mineral producers in Florida:  Florida  Bur. of Geology
     Inf. Circ. 66, ko p.

Nelsen, F. M., and F. T. Eggertsen, 1958, Determination of surface area:  Anal.
     Chem., v. 30, p. 1387-1390.

Oetking, P. F. [compiler], 1959, Geological highway map of Texas:  Dallas Geol.
     Soc., Dallas, TX.

Pessagno, E. A., Jr., 1969, Upper Cretaceous stratigraphy of  the western Gulf
     Coast area of Mexico, Texas, and Arkansas:   Geol.  Soc. America Mem. Ill,
     139 P-

Purdue University Cooperative Extension Service, 1971,  Sources  and analyses
     of liming materials:  Agronomy Dept. Rept.  6k, Lafayette,  IN, 25 p.

Puri, H. S., 1957, Stratigraphy and zonation of  the Ocala Group:  Florida Geol.
     Survey Bull. 38, 21*8 p., h pis.

Raben, I. A., 1973, Status of technology of commercially offered lime and
     limestone flue gas desulfurization systems, in_ Flue Gas  Desulfurization
     Symposium Proc., Sponsored by Control Systems Laboratory,  Environmental
     Protection Agency, New Orleans,  LA, May 1^-17-

Reeside, J. B-., Jr., 1932, Stratigraphic nomenclature  in the  United States:
     Internat. Geol. Cong. XVI, Guidebook 29: Washington, DC:  U.S. Govt.
     Printing Office, 7 p., 10 pis.

Reves, W. D., 196l, The limestone resources of Washington, Holmes and Jackson
     Counties, Florida:  Florida Geol. Survey Bull. U2, 121 p.

Robison, E. B., A. H. Bagnulo, J. W.  Bishop, and S. Ehrlich,  1970, Characteriza-
     tion and control of gaseous emissions from  coal-fired fluidized-bed boilers:
     Pope, Evans and Robbins, Div. Perathon Incorporated (Alexandria, VA),
     Interim Report to U.S. National  Air Pollution Control Administration,
     Oct., 1970, 133 p.

Rochelle, G. T., 1973, Economics of flue gas desulfurization, in_ Flue Gas
     Desulfurization Symposium Proc., sponsored  by Control Systems Laboratory,
     Environmental Protection Agency, New Orleans, LA,  May 1^-17.

Runnels, R. T., and I. M. Dubins, 19^9, Chemical and petrographic  studies  of
     the Fort Hays Chalk in Kansas:  Kansas Geol. Survey Bull.  82, pt.  1,  p.  1-36.

Searle, A. B., 1933, The chemistry and physics of clays and  other  ceramic
     materials, second ed.:  London:   Ernest Benn Limited, p. 538.

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                                   -  91  -
Segall, R. T., 1972,  Michigan mineral producers,  1971:   Michigan Geol. Survey
     Ann.  Directory 5,  p.  13.

Stephenson, L. W.,  1937, Stratigraphic relations  of the  Austin, Taylor, and
     equivalent formations in Texas:   U.S. Geol.  Survey Prof.  Paper 186-G,
     p. 133-1U6.

Terlecky,  P. M., Jr., in press, The origin of a late Pleistocene and Holocene
     marl  deposit:   Jour.  Sed. Petrology.

Thiel, G.  A., 1930, A correlation of marl  "beds with types  of glacial deposits:
     Jour. Geology, v.  38, p. 717-728.

Thomas, Josephus, Jr.,  and R. R. Frost,  1971, Versatile  apparatus  for  studying
     reactions involving gas adsorption  or evolution:  Illinois Acad.  Sci.
     Trans., v. 6b, no. 3, p. 21*8-253.

Toulmin, L. D., and others, 1966, Summary  of the  Tertiary  stratigraphy of
     south-central and southwest Alabama,  in_ Copeland,  C.  W. [ed.],  Facies
     changes in the Alabama Tertiary: Alabama Geol. Soc.  Guidebook U,
     University, AL, p. 3-10.

U.S. Bureau of Mines,  1969, Minerals yearbook - 1968, vols. I-II:   Washington,
     DC:  U.S. Govt. Printing  Office, p.  10U6.

U.S. Bureau of Mines,  1971, Minerals yearbook - 1969, vols. I-II:   Washington,
     DC:  U.S. Govt. Printing  Office, p.  1038.

Valentine, G." M., I960, Inventory of Washington minerals,  pt.  I, Nonmetallic
     minerals, second  ed.  (revised by M. T. Huntting):   Washington State
     Division of Mines and Geology Bull. 37, 175  p.

Vernon, R. 0., 19^3, Florida mineral industry:  Florida Geol.  Survey Bull.  2h,
     207 P-

Vernon, R. 0., and H.  S. Puri  [compilers], 1965,  Geologic  map of Florida:
     Florida Div. of Geology Map Series  18.

Wayland, J. R., and W. E.  Ham, 1955, General and economic  geology  of the  Baum
     Limestone, Ravia-Mannsville area, Oklahoma:   Oklahoma Geol.  Survey
     Circ. 33, 1+1* p.

Wayne, W.  J., 1971, Marl resources of Indiana:  Indiana Dept.  Nat. Resources,
     Geol. Survey Bull. 1*2-G,  l6 p.

Wilson, S. D., 1970? Suggested method of test for moisture-density relations of
     soils using Harvard compaction apparatus, in_ American Society for Testing
     Materials, Special procedures for testing soil and rock for engineering
     purposes:  ASTM Spec. Tech. Pub. 1*79, P- 101-103.

Zeller, D. E.  [ed.], 1968, The stratigraphic succession in Kansas:  Kansas
     Geol. Survey Bull. 189, p. l-8l.

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                                    APPENDIX 1


                          ANNOTATED BIBLIOGRAPHY ON MARLS
                 IN THE NORTHEASTERN QUARTER OF THE UNITED STATES


          This  bibliography includes works  on fresh-water marls that have  formed
in lakes  and "bogs  in the northeastern quarter of the United States.  In the
United States  such marls occur as commercial deposits only within this area.
Deposits  of  so-called marine marls from the Atlantic Coast have been excluded.


CONNECTICUT

Perry, J. B.,  18T3, Hints toward the post-Tertiary history of New England  from
     personal  study of rocks, with strictures on Dana's "Geology of the New
     Haven region":  Boston Soc. Nat. Hist.  Proc., v. 15, p. U8-1U8.

           Discussion of the marl and peat periods  of post-Pliocene time.


ILLINOIS

Athy, L.  F., 1928, Geology and mineral resources of the Herscher Quadrangle:
     Illinois  Geol. Survey Bull. 55, 120  p.
           Marl described (p.  108-109).

Baker, F. C.,  1912, Postglacial life of Wilmette Bay, glacial Lake Chicago:
     Illinois  Acad. Sci.  Trans. (1911), v.  U, p. 108-116.
           Describes a'marl bed about 5 inches thick (p.  109,  111-112).

Baker, F. C.,  1918, Postglacial Mollusca  from the marls of Central Illinois:
     Jour. Geol.,  v. 26, no. 7, p. 659-671.

           Describes 8- to 12-inch thick marl  bed on campus of University of
           Illinois, Urbana (p. 660).  Refers  to marls from Maine (p.  66l-
           663, 665).

Decker, C. E.,  1912,. A tufa deposit near  Danville, Illinois:  Illinois Acad.
     Sci. Trans.,  v. 5, p. 109-111.

           An unsuccessful search was made for this deposit in July 1971-

Lamar, J. E.,  1938, Unexploited or little known industrial minerals of Illinois:
     Illinois  Geol. Survey Circ. 23, p. 213-232.
           Describes shell  marl localities in  Illinois (p. 220-221).

Lamar, J. E.,  1965, Industrial minerals and metals of Illinois:  Illinois
     Geol. Survey  Ed. Ser. 8, U8 p.

           Brief account of deposits  of marl,  tufa, and travertine in Illinois.
           Includes names of counties in which some deposits have been worked
           (p. 46).

                                      - 93 -

-------
                                     - 9U  -

 Mosier, J. G., S. V. Holt, F.  A. Fisher, E. E.  DeTurk, H. J. Snider, and
      L. H. Smith, 1923,  Livingston County soils:   Univ. of Illinois Agr.  Exp.
      Sta. Soil Rept. 25, 55 p.

            Reports muck on marl in  SE£ Sec. 32, T.  30 N., R. 7 E. (p.  27).

 Powers, W. E., 1936, Geological  setting  of the  Aurora mastodon remains:
      Illinois Acad. Sci.  Trans.  (1935),  v. 28,  no.  2, p.  193-191*.

            Reports occurrence of 30 feet of marl (p.  193).  •

 Rubey, W. W., 1952, Geology and  mineral  resources  of the Hardin and Brussels
      Quadrangles (Illinois):   U. S. Geol. Survey Prof.  Paper 218, 179 p.

            Describes calcareous tufa deposits (p.  97-98).
 INDIANA

 Blatchley, W. S., and G. H.  Ashley, 1901, The lakes  of northern Indiana  and
      their associated marl  deposits:  i.n_ W. S. Blatchley, Indiana Dept.  Geol.
      and Nat. Resources,  25th Ann. Rept.  (1900),  p.  31-321.

 McGregor, D. J., 1958,  Cement  raw materials in Indiana:   Indiana Geol. Survey
      Bull. 15, 88 p.

            Use of marls in cement in Indiana (p. 14-).  Discussion of marl (p.  4-5,
              ); analyses  of marls (p. 50).
Wayne, W.  J., 1963, Pleistocene  formations in Indiana:   Indiana Geol. Survey
      Bull. 25, 85 p.

            Martinsville Formation defined to include a paludal  facies with cal-
            careous marl (p. 28-31).  Refers to sections of Martinsville Forma-
            tion that contain marl (p. 80).

Wayne, W.  J. , 1971, Marl resources  of Indiana:  Indiana Geol. Survey Bull.
      U2-G, 16 p.

            Distribution, production, and analyses  of marl deposits in
            Indiana .
MAINE

Dodge, J.  R.,  1868, On the limestone and pond-marls  of Maine:   U. S. Agricul-
     tural Rept., p. 370-371.

            Description of formations and localities with analyses;  special reference
            to fertilizing qualities.
MASSACHUSETTS

Hitchcock, Edward, 1833, Report  on  the geology, mineralogy,  botany, and
     zoology of Massachusetts:   Amherst:   J. S. and C. Adams,  xii p., 692 p.
           Marl occurrences (p. 38,  120).

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                                    -  95  -

Hitchcock,  Edward, l8Ul, Geology  of  Massachusetts,  v.  1:   Amherst:  J. S.  and
      C.  Adams, 299 P-
            Discussion of marl with locations (p. 67-75);  analyses of marls  (p. 70).
            Discussion of green sand  (marl) with analyses  (p. 91-95).
MICHIGAN

Cook,  C. W.,  1912, Michigan  cement:   Michigan Geol.  and Biol. Survey Pub.
     8,  Geol.  Ser. 6, p. 337-35^.
            Discussion of marls (p. 338-3^2) and analyses of marls (p. 3^1).  Use  of
            marl by plants (p. 3^-350).

Davis, C.  A.,  1900, A contribution to the natural  history of marl:  Jour.
     Geol., v. 8, no. 6, p.  U85-^97-

Davis, C.  A.,  1900, A remarkable  marl lake:  Jour. Geol., v. 8, no. 6,  p.  ^98-
     503.

Davis, C.  A.,  1901, A second contribution to the natural history  of marl:
     Jour. Geol., v. 9, no.  6, p.  1*91-506.

            Three papers by Davis describe marl that  occurs in certain lakes
            in  Michigan (Montcalm, Branch, and Isabella Counties) and dis-
            cuss the origin of the marl derived from  chemical processes of
            plants, especially Chara that grows on the  bottoms of the lakes.


Hale,  D.  J.,  and  others,  1903, Marl  (bog lime)  and its application  to  the
     manufacture  of  portland cement:  Michigan Geol. Survey, v. 8,  pt.  3,
      399 p.

Klyce, D.  F., and R. J. Bishop, 1971, Mineral  industry of Michigan  1969:
     Michigan Geol.  Survey Ann. Statistical Summ.  13, 18 p.

            Agricultural production of marl (p.  8).  Quantity and value of marl
            production for 1968 and 1969 (p. 9)-  Principal marl producers listed
            (p. 18).

Segall, R. T., 1972, Michigan mineral producers 1971:  Michigan  Geol.  Survey
      Ann.  Directory  U,  52 p.
            List of marl producers (p. 13).
 MINNESOTA

 Armstrong, L.  C.,  1927, The geologic  conditions favorable  for the accumulation
      of marl,  with special reference  to east central Minnesota:   Univ. of Min-
      nesota, Minneapolis, E. M. thesis.

 Emmons, W. H., and F. F. Grout, eds., 19^3, Mineral resources of Minnesota:
      Minnesota Geol. Survey Bull.  30, 1^9 p.

            Section on marls (p. 101-105,  108); includes map of distribu-
            tion and number of deposits per  county.

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 Kirk,  R.  E.,  1926, The manufacture of portland  cement from marl:  Univ.  of
      Minnesota Eng. Expt. Sta.  Bull,  h,

 Roepke, H. H., 1958, The Nisswa Lake  marl deposit,  Crow Wing County, Min-
      nesota:   Univ. of Minnesota,  Minneapolis,  M.S.  thesis.
            See G. M. Schwartz  below.

 Schwartz, G.  M., et al., 1959,  Investigation of the  commercial possibilities
      of marl  in  Minnesota:  St.  Paul:   Office of Iron Range Resources  and
      Rehabilitation (in coop, with the Minnesota Geol.  Survey and Univ.  of
      Minnesota,  Minneapolis), xiii p., 99 p.

            'Among other subjects related to production and uses  of marl, this
            book contains chapters on methods of chemical analyses of marl,
            investigation of marl deposits, and experiments  on drying marl.
            Chapter IV is a reprint of H. H. RoepkeTs  thesis on  the Nisswa
            Lake marl deposit.
            Appendix A is a reprint of C. R. Stauffer  and G. A.  Thiel's paper,
            1933, "The limestones and marls of Minnesota":   Minnesota Geol. Sur-
            vey Bull. 23,  pt. II (p. 79-190).

 Minnesota Geological Survey.  Marl:  Minnesota  Geol.  Survey Misc. Rept.  8,  3 p.

            Defines marl and lists five large marl deposits  in Minnesota.  Counties
            having large marl tonnages include Crow Wing, Wright, and Stearn.  Lists
            uses of limestone and marls.

 Stauffer, C.  R.,  and G.  A. Thiel,  1933,  The limestones  and marls  of Min-
      nesota:   Minnesota Geol.  Survey Bull.  23, 193 p.

            Uses of marl (p.  1-8).  Part II, "The marls of Minnesota" (p. 79-190) has
            been reprinted as Appendix A in G. M.  Schwartz et al., 1959.


 Thiel,  G.  A., 1930,  A correlation  of marl beds with types  of glacial deposits:
      Jour. Geol.,  v. 38,  no. 8, November-December, p. 717-728.

 Thiel,  G.  A., 19U6,  Marl:   Conservation  Volunteer, v. 9, no.  51,  March-
      April,  p. 13-15-

 Zumberge,  J.  H., 1952, The lakes of Minnesota, their origin  and classifica-
      tion:   Minnesota Geol.  Survey Bull. 35, xiii  p., 99 p.
            Discussion of marls in lakes (p. 69,  71-72).


NEW HAMPSHIRE

Hitchcock, C.  H., 1871*, The  geology of New Hampshire:  Part  I.  Physical
      geography:  Concord,  NH:   Edward A. Jenks,  xi p., 667 p.

           Information on marl  localities  (p. 5^9).

Hitchcock, C.  H. ,  1878, The  geology of New  Hampshire:  Part  V.  Economic.-
      geology:   Concord, NH:  Edward A. Jenks,  103  p.

           Gives marl localities  (p. 95).

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                                     - 97 -

NEW  JERSEY

Cook,  G.  H., 1868, Geology of New  Jersey:   Newark, xxiv p.,  899  p.
            Discussion of shell-marl, calcareous sinter, calcareous tufa,
            and travertine (p. 170-172).

Kummel, H.  B., 1901, Report on the  portland cement industry:  New Jersey Geol.
     Survey Ann.  Kept, of the State Geologist for the year 1900, pt.  2, p. 9-
     101.

            Numerous and very small lake deposits of marl are described (p.  98-101);
            analyses (p. 98).
NEW YORK

Graham, J.  A.,  1955, The mineral  industries of New York State  19*19-1959:   New
     York State Mus. and Science  Service  Circ. 1*1, 76 p.

            Report of one marl producer in Livingston County in 19^9 giving
            quantity and value of production (p.  30).

Hartnagel,  C.  A.,  1927, The mining and  quarry industries of New York  from 1919
     to 192U  including lists of operators:   New York State Mus. Bull.  273, 102 p.

            Marl discussed (p.  52-54). Dunkirk operator reporting production
            in
Hartnagel,  C.  A., and J. G. Broughton,  1951, The mining and quarry  industries
     of New York State, 1937 to 19^8:   New York State Mus. Bull.  3^3,  130 p.
           Use of marl in portland cement (p. 23-24).

Luedke, E.  M. , C. T. Wrucke, and J.  A.  Graham, 1959, Mineral  occurrences of
     New York State with selected references to each locality:  U.  S.  Geol.
     Survey Bull. 1072-F, p. iii , p.  385-MtU.
            Marl  occurrences (p. 420-421).

Newland, D.  H. ,  1912, The mining and quarry industry of New York  State:   Report
     of operations and production during  1911:  New York State  Mus.  Bull. l6l,
     114 p.
            Marl discussed (p.  80-8l).

Newland, D.  H.,  1921, The mineral resources of the state of New York:   New
     York State  Mus. 'Bull. 223, 22*;  (1919), 315 p.
            Marl discussed (p.  145-149);  chemical analyses  (p. 14?).

Newland, D.  H. ,  and C. A. Hartnagel,  1936, The mining and quarry  industries
     of New York State for 1930 to 1933:   New York State Mus. Bull.  305, 95 p.
            Discussion of marl  (p. 48-52).  Little marl now being produced
            (p. 51-52).

Ries , Heinrich,  and E. C. Eckel, 1901,  Lime and cement industries of New York:
     New York State Mus. Bull., v. 8, no.  UU, 968 p.

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                                        -  98 -
Terlecky, P. M.,  Jr., 1972, The origin,  stratigraphy and post-depositional
     history of a late Pleistocene marl  deposit, Rochester, N.Y.  area (abstract),
     in_ Northeastern Section, Geological Society America Program,  7th Ann. Mtg.,
     March  9-11,  p. 9-11.

             Report of a  study at locality 7133.
OHIO

Kefauver, Hazel,  ed., I960, Annual coal  and nonmetallic mineral  report with
     directories  of reporting firms for  I960:   Ohio Dept. Indus.  Relations,
     290 p.
           One marl producer listed  (p. 244).

Stout, Wilber,  1940, Marl, tufa  rock, travertine, and "bog ore  in Ohio:  Ohio
     Geol. Survey Bull. 41, % p.
PENNSYLVANIA

Dickey, J. B.  R.,  1923, Calcareous marl  in Pennsylvania south  of the terminal
     moraine:   Pennsylvania Geol. Survey Bull.  76, 10 p.

Miller, B. L., 1934, Limestones of Pennsylvania:  Pennsylvania Geol. Survey
     Bull. M 20,  729 p."

           Marl deposit in Crawford County described {p.  332-335);  analyses  (p. 335).
           General discussion of marls  (p. 54-56).  Repeats descriptions of  marls
           from Dickey (1923)  (p. 167, 292, 345-346,  388, 394, 423, 499, and 700).
           Describes  concretions (p.  475-477). Reports marl locations (p. 387 and
           714).
VERMONT

Hitchcock, Edward, Edward Hitchcock,  Jr.,  A. D. Hager, and  C.  M.  Hitchcock,
     l86l, Report on the geology of Vermont:  descriptive,  theoretical,
     economical, and scenographical,  Vols. I and II:  Claremont  Manufacturing
     Company,  Claremont, NH, 988 p.

           Marls discussed (p.  167-171, 725-726,  and 805-806);  analyses {p.  168,
           697-698, and 805).
VIRGINIA

LeVan, D.  C.,  1971, Directory of the  mineral industry in  Virginia—1971:
     Virginia  Div.  of Mineral Resources , 46 p.

           Lists four marl producers  (p. 27-28),  one fresh-water marl producer
           (J. C. Digges), and three  producers of marine shell marls.
           **<>•»• 1 a

McGill,  W. M.,  1936, Outline of the mineral resources of  Virginia:  Virginia
     Geol. Survey Bull. 47, Ed. Ser.  No. 3, 81 p.

           Calcareous  (shell) marl and travertine discussed (p. 36).

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                                     -  99  -

WEST VIRGINIA

Davies , W. E. ,  1949, Caverns of West  Virginia:  West Virginia Geol. Survey,
     v. 19,  x p.,  353 p.
            Marl deposits  (p. 5).  Shelter caves present in marl bed at.
            Williamsport  (p. 60).

Gillespie, ¥. H.,  and J. A. Clendening, 196 4, An interesting marl deposit  in
     Hardy  County, West Virginia:   West Virginia Acad.  Sci. Proc., v. 36,
Grimsley,  G.  P., 1906 , Clays,  limestones, and cements:   West Virginia Geol.
     Survey,  v.  3 (1905), xviii p.,  565 p.
            Marl  reported with analysis (p. 515-516).

Grimsley,  G.  P., 1916, Jefferson, Berkeley, and  Morgan  Counties:  West Virginia
     Geol.  Survey County Repts.,  xxvi p., 644 p.
            Marl  deposits discussed (p. 393-396);  analyses (p.  39^-396).

McCue,  J.  B., J. B. Lucke ,  and H. P. Woodward, 1939,  Limestones of West  Virginia:
     West  Virginia Geol. Survey,  v.  12, xiv p.,  560 p.
            Marl  locations mentioned  (p.  98, 102, 115,  153, 204, 211-213, ^55,
                   ; analyses of marls  (p. Ill, 160,  2l6, 396, M-28) .
Price,  P.  H., R. C. Tucker,  and 0. L, Haught,  1938, Geology and natural
      resources of West Virginia:  West Virginia Geol.  Survey, v. 10,  xi p.,
      462 p.
            Calcareous tufa, travertine, and calcareous marl described as minor
           -cement materials .  Refers  to use by only two plants at Charles Town
            (p.  302, 305).

Reger,  D.  B., and R.  C.  Tucker, 1924, Mineral  and Grant Counties:  West Virginia
      Geol. Survey County Repts., xxiv p., 866  p.
            Discusses marl  deposits (p. 675-676); analyses  (p. 678); and locations
            (p.- 680).

Tilton, J. L., W. F.  Prouty , and P. H. Price,  1927, Pendleton  County:  West
      Virginia Geol. Survey County Repts., xviii p., 38U p.
            Marls discussed with one location  given (p. 289); photograph of
            outcrop (p. 288).

Tilton, J. L., W. F.  Prouty, R. C. Tucker,  and P.  H. Price, 1927,  Hampshire and
      and Hardy Counties:  West Virginia  Geol.  Survey County Repts.,  xxii p.,
      624 p.
            Travertine  locations given (p.  18 and 138).  Photograph  of marl  deposit
            (p. 140).   Marl analyses (p. 274,  308, 554).  Marl deposits discussed
            (p. 271,  308).
Woodward, H. P., 1951,  Ordovician System of West Virginia:  West Virginia  Geol.
      Survey, v. 21, xi p., 627 p.
            Discusses marl deposits in vicinity of Charles Town (p.

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                                      -  100 -

WISCONSIN

Natural Resources  Committee of State Agencies of Wisconsin, 1956,  The
      natural resources of Wisconsin:   Wisconsin Nat. Resources  Comm.  of
      State  Agencies, 159 p.
            Marl discussed (p. 109).  Gives production of agricultural lime of
            four counties in 1952-

Ostrom, M.  E.,  1970, Directory of Wisconsin mineral producers.   1968:  Wis-
      consin Geol.  and Nat. History  Survey Inf. Circ. 12,  68 p.
            One marl producer listed (p. 57).

Steidtmann, Edward, 192^, Limestones  and marls of Wisconsin:  Wisconsin Geol.
      and  Nat. History Survey Bull.  66, 208 p.
            Origin of marls (p.  6); the marls  of Wisconsin (p. 128-153); uses of
            marl (p. 98,  111-116).

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Appendix 2 begins on page 102.
            - 101 -

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                                                                   APPENDIX 2

                                              SOURCES OF SAMPLES AND  REMARKS  ON THE DEPOSITS
Location and    Thickness
   sample      represented
   number         (ft)
    7124
10+
                    Type
                                  Source and location
                             (quadrangle map in parentheses)
                                                         Remarks on the deposit
                                                        and geologic unit sampled
7120


7121A
7121B




7122A
7122B
35


0.5
3.5+




2
5



\
J




\
J
Limestone, chalky
(coquina)

Shells and broken
shells




Limestone, chalky
Coquina
Houdail le -Duval -Wright
5 mi NE of Newberry,
9S-17E (Newberry Quad
Turtle Beach of Siesta
bar, 3 mi N and 2 mi
SE£ Sec. 23, 37S-18E
Quad., PL).


J. Cochran pit, 4 mi W
Rt. 80) of La Belle,
Co. quarry,
PL; SE£ Sec. 23,
., PL).
Key, offshore
W of Osprey, PL;
(Bird Keys



and 2 mi N (off
PL; SE£ Sec. 13,
Extensive deposit in the Crystal River
Formation (Eocene).

Anastasia Formation (Pleistocene). No notable
deposit at this locality. Samples considered
typical of shells of the Anastasia, which
occurs for many miles south of Turtle Beach , '
along the Gulf Coast. H
ro
Operating pit extends over about 5 acres in 1
the Caloosahatchee Marl (Pleistocene).
                                                         43S-28E (Sears Quad.,  PL).

                                Sandstone, calcareous   Outcrop on north bank of Caloosahatchee
                                                         River, north side of La Belle, PL;
                                                         Sec. 32, 42S-29E (La Belle  Quad., PL)
Clam shells
Radcliff Materials,  Inc.,  Mobile,  AL.
  Lake Pontchartrain,  LA (30°10'N,  90°
  05>W).
                                                                                  Sandy facies of Caloosahatchee Marl  (Pleisto-
                                                                                    cene) .
Dredging operation in Lake Pontchartrain, LA
  (Holocene).
    7125


    7126A

    7126B
                   10+
             Oyster  shells
             Bog marl
                       Radcliff Materials, Jnc., Mobjle, AL.
                         Mobile Bay, AL (30 32'N, 88 02'tf).
                       Woodrow Gary, New Madison, OH.  Pit
                         location in SEtr SWi Sec. 1, ION-IE
                         (New Madison Quad., OH).
                                              Dredging operation in a dead oyster  reef  in
                                                Mobile Bay, AL (Holocene).

                                              Former operations extended over about a
                                                5-acre bog (Pleistocene).
                                              Upper beds exposed near center  of deposit.

-------
712?A
0.5
Tufaceous bog marl
7127B

7127C

7127D


7128A

7128B


7129
0.8

2.5
15
Clayey and marly
  silt
Clayey and marly
  silt
Tufaceous bog marl
             Tufaceous bog marl
Tufaceous bog marl
Abandoned pit, 1.3 mi N of intersection Rt.
  269 and NYC RR at Castalia, OH, and 0.65
  mi W.  In Resthaven Wildlife Area
  (Castalia Quad., OH).
                        Abandoned pit in road embankment.
                          S of 7127 (Castalia Quad., OH).
                                   0.6 mi
Abandoned pit, SE£ SE£ Sec. 15, 20N-1JW,
  1.1 mi SW of McZena, OH (Loudonville
  Quad., OH).
Sample from plowed surface of a 10-acre field
  adjacent to an extensive bog deposit form-
  erly operated by a cement company (Pleisto-
  cene) .

0.5 to 0.8 ft below sample 7127A above.

0.8 to 3.8 ft below sample 7127A above.

Typical of the large lumps present in deposit
  (Pleistocene).

Same deposit as 7127 0.5 ft to 1.5 ft below
  surface of embankment.
Same deposit as 7127 1.5 ft to 3.0 ft below
  surface of embankment (Pleistocene).

Sample from edge of old road bed used during
  production of marl from a moderate size
  bog.  Probably typical of marl underlying
  the small lake 20 yards to the west
  (Pleistocene).
                                                                                                                                                 o
                                                                                                                                                 oo
7130
2.5
Bog marl
Abandoned pit, 0.7 mi S of intersection
  Rt. if-24 and Frisbee Rd. and 0.2 mi due
  east (Cassadaga Quad., NY).
Old portland cement plant.  Sample from below
  1.5 ft of muck and adjacent to water-filled
  pit in a moderately extensive bog (Pleisto-
  cene ) .
7131A
7131B
7131C
7132A
7132B
7132C

7132D
2.8
5-5+
6

20
             Bog marl
Bog marl
                        Jasper Robinson, 0.5 mi SW of Clarendon,
                          NY (Holley Quad., NY).
Scofield Lime Products, Fancher, NY.   Pit 0.5
  mi S of intersection of Rt.  19 and  New York
  Throughway and 0.1 mi W of Rt. 19
  (Churchville Quad., NY).
                                               Samples from a 10 to 15 acre area (Pleistocene),
Commercial operation in a Pleistocene bog.
Sample A from upper marl, center of pit.
Sample of marl under 7132A.
Sample of the upper part of the marl in the
  north end of the pit.
Sample from stockpile.

-------
                                                              APPENDIX 2,  continued
Location and    Thickness
   sample      represented
   number         (ft)
                    Type
                                   Source  and  location
                             (quadrangle map in parentheses)
                                                         Remarks on the deposit
                                                        and geologic unit sampled
    7133
    7135
    7136
5-5
                   1-5
1.0
2.0
Tufaceous bog marl
             Lake marl
Bog marl
Tufaceous bog marl
Abandoned pit of the Genesee Lime
  Products Co., Rochester, NY.   Pit
  located 1.0 mi E and 0.8 mi N of
  Caledonia, NY (Caledonia Quad.,
  NY).

Abandoned pit 0.9 mi SW (on Rt. 34-5)  of
  Wayland, NY (Wayland Quad., NY).
John Underwood, Camillus,  NY.   Pit
  located 1 mi S and 1 mi  W of Warners,
  NY (Camillus Quad., NY).

Outcrop under Penn.  Cent.  Railroad
  bridge over Letort Spring Run Creek in
  Carlisle, PA (Carlisle Quad., PA).
Sample from auger hole in an extensive bog
  (Pleistocene).
Extensive areal deposit (Pleistocene).
  Sample from auger hole on edge of lake..
  Marl is underlain by muck and gravel  at
  the site of the auger hole.

Abandoned Portland cement pit  and plant.
  Workings in an extensive bog (Pleistocene).
Very limited deposit (Pleistocene).
                                                                                                                                                    H
    7137
20
Bog marl
J. C, Digges & Sons,  White Post,  VA.   Pit
  and plant located £ mi S of Rt. 617  at
  point 0.65 mi E of  intersection of fits.
  255 and 617, near Briggs (Boyce Quad.,
  VA).
Commercial operations in an extensive  bog
  deposit (Pleistocene) above water table.
  Sample representative of pit production.
    7138
5-5
             Lake marl
                        Sampsel & Son,  R.R.  1, Rochester, IN.
                          on east side  of Lake 16,  2 mi E of
                          Athens, IN, NWi SE£ Sec.  16, JON-^E,
                          Fulton Co.  (Akron  Quad.,  IN).
                                       Pit     Discontinued operations.  Sample from above
                                                water level.  More than 4 ft of similar
                                                marl occurs below the beds sampled
                                                (Pleistocene).

-------
7139
10-12
              Bog marl
714-0
 5.5+
              Lake marl
Stanley Ouster, R.R.  1, Box 1, Milford,
  IN.  Pit on east side of Rt. 15 on the
  north edge of Milford, IN, NW£ NE£ Sec.
  8, 3^N-6E, Kosciusko Co. (Milford
  Quad., IN).

Raymond Beezley,.R.R. k, Albion, IN.
  Erdly pit located on Whirledge Lake
  1 3A mi E of Kimmell, IN, Cen. E-J
  NEv Sec.  19, 34N-9E, Noble Co.
  (Ligonier Quad., IN).
Discontinued operation.  Sample from stockpile
  from a 4 to 6 acre bog (Pleistocene).
Commercial operations on the east side of lake.
  Sample from stockpile of Pleistocene marl.
               7+
              Bog marl
7142
16-18
              Lake marl
                            Bog marl
              12-18
              Lake marl
Vernon Kaufman, R.R. 1, Topeka, IN.
  Fought pit located 3 mi E and 1 mi S
  of Topeka, IN, NW£ NW£ NW^ Sec. 3,
  35N-9E, Noble Co. (Oliver Lake Quad.,
  IN).

Miller Marl Co., R.R.  1, Middlebury, IN.
  Pit on south end of Cass Lake, 3 mi E
  of Middlebury, NW£ Sec. 5, 37N-8E,
  La Grange Co. (Middlebury Quad., IN).

K. Fleming, Fremont, IN.  Pit on west
  edge of Fremont, SW^, SE£ Sec. 20,
  38N-14-E, Steuben Co. (Angola East
  Quad., IN).

Taylor & Son, R.R. 2,  Fremont, IN.
  Garman Pit on Warner Lake, l^ mi E
  and 1 mi S of Orland, Cen. W-| Sec.
  27, 38N-12E, Steuben Co. (Orland
  Quad., IN).
Commercial operations in a Pleistocene bog.
  Sample from stockpile.
                                              I
Commercial operations.   Sample from stockpile  |_,
  of Pleistocene marl.                         ^
                                              I
                                                                                    Abandoned pit in a large Pleistocene bog.
                                                                                      Sample from stockpile.
Commercial operations in a Pleistocene  lake.
  Sample from stockpile.

-------
                                                              APPENDIX 2,  continued
Location and    Thickness
   sample      represented
   number         (ft)
                     Type
                                   Source  and location
                              (quadrangle  map in parentheses)
                                                         Remarks on the deposit
                                                        and geologic unit sampled
    7145A
              Lake marl
    714 6A
10-15
Lake marl
    7147A
    7148
 20+
Bog marl
    7149A
    7149B
 12+
              Tufaoeous  marl
              (spring  deposit)
              Tufaoeous  bog marl
Bog marl
Harlan Spoor, R.R. 1, Burlington,  MI.
  Pit is 0.2 mi S of R Drive S Rd.,  2.5
  mi NW of Burlington, Cen.  N| Sec.  21,
  4S-7W, Calhoun Co. (Union City Quad.,
  MI).

Darrell Hamilton, Nashville, MI.   Pit
  on south side of Thornapple Lake,  4
  mi W of Nashville, NE£ NW£ NE£ Sec.
  30, 3N-7W, Barry Co. (Nashville  Quad.,
  MI).

S. K. Vorres, Fremont, MI.   Pit is 5
  mi N of Fremont, on the east side  of
  Luoe Rd., Cen. Sec. 6, 13N-13W,
  Newaygo Co. (White Cloud  Quad.,  MI).

Grant Tufa Lime Co., Grant,  MI.  Pit
  is 7 mi E of Grant, NWi NE£ Sec. 29,
  11N-11W, Newaygo Co. (Sand Lake
  Quad., MI).

Gerald Arnsman, R.R. I, Hopkins, MI.
  Belden Pit, 0.5 mi E of South Monte-
  rey, MI, SEj SE$ NWi Sec.  34,  3N-13W,
  Allegan Co. (Allegan Quad., MI).
                                                                      Commercial operation in a Pleistocene lake.
                                                                        Sample from stockpile.
Commercial operation on the southeast edge of
  a Pleistocene lake.  Sample from stockpile.
Location of pit from which marl (Pleistocene)
  was dug for full-scale tests by TVA.   Sample
  from depleted stockpile.
                                                                      Abandoned operations in a Pleistocene spring
                                                                        deposit.
Commercial operation in a Pleistocene bog.
Sample A from upper tufaceous beds in cen-
ter of pit.

Sample B from lower beds.
                                                                                                                                                    o
                                                                                                                                                    ON
                                                                                                                                                    I

-------
7150
               20
                            Lake marl
7152
               20+
5+
7155
7155
               5-10
3.5+
7156
3.5 +
             Bog marl
Bog marl
             Sludge from paper
               mfg. plant
             Bog marl
                            Lake marl
Bog marl
Leon Hayward Dry Marl, R.R. 2, Vicksburg,
  MI.  Marl is dredged from beneath the
  south side of Indian Lake, 3 mi NE of
  Vicksburg in Sec. 8, iJ-S-lOW, Kalamazoo
  Co. (Leonidas Quad., MI).

Poehlman & Sons.-R.R. 2, Cassopolis, MI.
  Operations are 6 mi SW of Cassopolis,
  SEtr NE£ Sec. 13, 7S-16W, Cass Co.
  (Cassopolis Quad., MI).

Lime Products Co.  Former dredging 3-5
  mi N of Eagle, WI, in SW£ SE£ Sec. 3^,
  6N-17E, Waukesha Co. (Eagle Quad., WI).
Nekoosa Edwards Paper Co., Port Edwards,
  WI.  Sludge pond east side of river at
  Nekoosa, WI, SE£ Sec. 10, 21N-5E, Wood
  Co. (Wisconsin Rapids Quad., WI).

Floyd Helgeson, R.R. 1, lola, WI.  Pit 3
  mi NW of lola, SWir NEi Sec. 21, 24N-11E,
  Waupaca Co. (Tigerton Quad., WI).

Clifford Caldwell Marl Co., Scandinavia,
  WI.  Pit is on south side of Marl Lake,
  3 mi SW of Scandinavia, W|- NWir Sec. 33,
  23N-11E, Waupaca Co. (Waupaca Quad.,
  WI).

A. E. Stelter, Bloomer, WI.  Neitzel pit
  along O'Neal Creek, 5.5 mi E of Bloomer
  on Rt. 6lf, SW£ SWi Sec. 33, 3N-8W,
  Chippewa Co. (Bloomer Quad., WI).
                                                                                   Commercial operations in Pleistocene lake.
                                                                                     Sample from stockpile.
                                                                      Commercial operations in Pleistocene marl.
                                                                        Samples of three typical marl types from
                                                                        the pit.
Abandoned operation in a Pleistocene bog.
  Samples represent upper U ft of marl at
  three different places along former
  workings.  Area is within Kettle Moraine-
  State Forest.

Waste product from Kraft paper process,
  sold to area farmers as ag lime, consists
  of more than 95$ CaCO,.
                                                                      Dredging operations have been discontinued
                                                                         in a Pleistocene bog.  Sample from stock-
                                                                         pile.

                                                                      Dredging operations have been discontinued
                                                                         in the Pleistocene lake.  Sample from the
                                                                         upper 3.5 ft at water's edge.
Abandoned pit in a Pleistocene bog.   Sample
  from upper 3 to 5 ft adjacent to pond.
                                                                                                                     I
                                                                                                                     H
                                                                                                                     O

                                                                                                                     I

-------
                                                              APPENDIX 2,  continued
Location and    Thickness
   sample      represented
   number         (ft)
                     Type
                                  Source and location
                              (quadrangle map in parentheses!
                                                         Remarks on the deposit
                                                        and geologic unit sampled
    7157A

    71573
    7157C
    7157D

    7158
15-18

 2.5
 3.5
 2.0
Lake marl
              Lake  marl
Burnett County Highway Dept.,  Siren,  WI.
  Pit located on northeast shore of Wood
  Lake, 8 mi W and 2 mi S of  Siren, NW£
  SE£ Sec. 27, 38N-18W, Burnett Co.
  (Milltown Quad., WI).

Sorum's Marl Service, Remer,  MN.  On  the
  south shore of Birch Lake,  2 mi SE  of
  Remer, near Cen. N£ Sec. 8,  141N-25W,
  Cass Co., MN (Hibbing 1:250,000 Quad.,
  MN).
Operations in a Pleistocene lake deposit.
Sample A from stockpile.

Uppermost beds of marl.
2.5 to 6 ft below top of marl.
6 to 8 ft below top of marl.

Commercial operations in a Pleistocene  lake
  deposit.  Sample from stockpile.
                                                                                                                                                   o
                                                                                                                                                   00
    7159
 13
Bog marl
    7160
    7l6l
 2.5
 1.0+
Bog marl
Bog marl
Richard Nanik Marl, Staples,  MN.   Pit
  located along Tower Creek,  10.5  mi N
  of Staples, NE£ NW£ Sec.  13,  136N-33W,
  Wadena Co. (Brainerd 1:250,000 Quad.,
  MN).

Lily pond on Urbana campus, Univ.  of
  Illinois, near Cen. Sec.  18,  19N-9E,
  Champaign Co. (Urbana Quad.,  IL).

Along Blackberry Creek, 5 mi  due west
  of Fox River at Aurora, IL, NE^  NE-J-
  SW£ Sec. Ik, 38N-7E, Kane Co.  (Geneva
  Quad., IL).
Commercial operations in a Pleistocene  bog.
  Sample from upper beds below muck.
Excavation exposure.   Sampled  in 19^7 as
  NF1J46 (Pleistocene).
Outcrop of marl.   Sampled in 1933  as  NP153
  (Pleistocene).

-------
7162 A
7162B
71620
7162D
12+
Bog marl
Delmer Ford, Chatsworth, IL.  Located 5
  mi S and 2 mi W of Chatsworth along
  creek north side of road SEir SW^ Sec.
  32, 26N-8E, Livingston Co. (Sibley Quad.,
  IL).
                                                                                    Discontinued operations in a Pleistocene bog.
                                                                                      Samples from four types of marl from stock-
                                                                                      piles.  The marl occurs under various
                                                                                      thicknesses of Grayslake Peat.
7163A
7163B
7163C
7163D
7201
7202
7203
7203D
1.2+
0.2
5.8
21
60
50±
15
30-50
                            Bog marl
Chalk
                            Chalk
               Coquina
                      Batavia Soil Builders.   Located  2.5  mi W
                        of Batavia,  IL,  SW£ SWi Sec.  19, 39N-8E,
                        Kane Co.  (Geneva Quad., IL).
Lone Star Industries Inc. quarry, west
  side of Tombigbee River, 2.2 mi  NE
  of St. Stephens, Washington Co., AL.

Lone Star Industries Inc. quarry,
  Demopolis, Marengo Co., AL.

Lone Star Industries Inc. pit,
  east side of Rt. 10, 1^ mi N of
  Chuckatuck, VA.
                                                                                    Marl occurs under 3 ft of Grayslake Peat.
                                                                                      Currently the peat is being produced.
                                                                                      Boring taken on the west side of bog.
                                                                                      Sample A from lower marl beds (Pleistocene!
                                                                                    Sample from middle marl bed.
                                                                                    Sample from upper marl beds.
                                                                                    Sample from stockpile near center of north
                                                                                      end of bog.

                                                                                    Marianna Limestone, Vicksburg Group
                                                                                      (Oligocene).  Large quarry.
                                                                     Demopolis Chalk Formation, Selma Group
                                                                        (Upper Cretaceous).  Large quarry.

                                                                     Yorktown Formation, coquina facies
                                                                        (Miocene).   Sample  7203  is composite of
                                                                        three samples  taken from the upper 15 ft,
                                                                        exposed  in  pit.   7203D from stockpile
                                                                        after plant processing.
                                                                                                                                  O
                                                                                                                                  vo
7201
7205
3-5
20-25
                            Chalk
                            Chalk
                      Outcrop on Rt. 12,  f- mi W of Jet.  with
                        Rt. 6l, 5.8 mi S  of Newbern,  Hale Co.,  AL.
                      Outcrop north side of Rt. 80 at Faunsdale,
                        Marengo Co.,  AL.
                                                Arcola Limestone Mbr.  of Mooreville  Chalk,
                                                  Selma Gr., (Upper Cretaceous).   Sample
                                                  from soft chalky beds.
                                                Demopolis Chalk (upper part!
                                                  (Upper Cretaceous).
                                                                                                                               Selma Gr.

-------
                                                             APPENDIX 2, continued
Location and
   sample
   number
 Thickness
represented
   (ft)
      Type
           Source and location
      (quadrangle map in parentheses)
           Remarks on the deposit
          and geologic unit sampled
    7206
  15
Chalk, clayey
Outcrop along Rt. 263, 0.1 mi S of Jet.
  with Rt. 21, near Braggs, Lowndes Co,,
  AL.
Prairie Bluff Chalk (lower part), Selma
  Group (Upper Cretaceous).
    7207
               Chalk,  clayey
    7208B
    7208C
  20
    7209
  16-17
    7210A
    721 OB
  12
  16-17
               Chalk & calcareous
                 shale
Chalk
Chalk
Limestone, chalky
  and clayey
Limestone, chalky
  and clayey
                        Outcrop along Rt. 263, 2.8 mi S  of Jet.
                          Lowndes Co. Rt. 7 and Alabama  Rt. 21,
                          Southwest Braggs, Lowndes Co., AL.
                        Ideal Cement Co.,  Superior,  NB,  quarry
                          located 6 mi SW  of Superior in Kansas,
                          Sec. 6, 15-7W,  Jewell Co., KS.
Nelson Quarry of Hopper Bros.,  Weeping
  Water, NB.  Located 1 mi S of Nelson,
  NB, on E side Rt. 11, SE£, SEir
  Sec. 36, 3N-7W, Nuckolls Co., NB.

Hebron Quarry of Hooper Bros.,  Weeping
  Water, NB.  Located 2.6 mi W  of  Gllead
  on Rt. 136, then 0.6 mi N, Thayer  Co.,  NB.
Prairie Bluff Chalk, Selma Group (Upper
  Cretaceous).  Sample taken from beds
  Just above the phosphatic and cobbly
  chalk beds at base of the Prairie
  Bluff.

Smoky Hill Chalk Mbr. (lower 3 ft) of
  Niobrara Chalk (Upper Cretaceous).
  Chalk and chalky shale (beds 0.5" to
  8" thick) interbedded.  Overlies 7208C.
Pt. Hays Limestone Mbr..of Niobrara
  Chalk.  Beds 0.8 to 3 ft thick sepa-
  rated by 0.5" shale partings.  Quarried
  by ripping.

Ft. Hays Limestone Mbr. of Niobrara Chalk
  (Upper Cretaceous).  Beds generally l"
  to 3" thick, separated by thin shale
  partings.
                                                                                                                                                    H
                                                                                                                                                    H
                                                                                                                                                    o
Greenhorn Limestone (Upper Cretaceous]
  buff beds generally 2" to 1"  thick;
  overlies 7210B.
Upper,
                                               Lower, gray strata, in 2" to 1" beds, partly
                                                 nodular and fossiliferous.

-------
7211
7212A

7212B
38

0.5
             Limestone, chalky
               and clayey
Chalk

Shale, chalky
Haddam Quarry of Hooper Bros.,  Weeping
  Water, NB.  Located F mi N of Rt. 36,
  0.7 mi E of Jet. of Rts.  22 and 36,
  Washington Co.,  KS.

Discontinued quarry along RR tracks, 1-|-
 mi W of Cedar, KS, SE^ SE£ Sec. 35, 4S-
 15W, Smith Co., KS.
                                                                        Greenhorn Limestone (Upper Cretaceous).
                                                                          Very small quarry,  intermittent  operations.
Ft. Hays Limestone Mbr. of Niobrara Chalk
  (Upper Cretaceous).  In beds 0.5 to 3 ft
  thick.
Sample representative of the 5 shale beds
  (each<2" thick) interbedded with
  chalk (7212A).
7213
              10*
                           Chalk
721UA

7214-B

72 in-c
17

19-3

18.2
Chalk

Chalk

Chalk
Outcrop west side of gravel road at
  Utility Sta. 3| mi N and 2 mi W of
  Hays, KS, cen. of E line Sec. 7,
  13S-18W, Ellis Co., KS.

Outcrop bluff on south side, west end
  of Cedar Bluff Res., Sec. 6, 15S-22W,
  Trego Co., KS.
Ft. Hays Limestone Mbr. of Niobrara Chalk
  (Upper Cretaceous).  In beds 1-2 ft thick
  interbedded with two 3" beds of chalky
  shale that were excluded from sample.

Ft. Hays Limestone Mbr. of Niobrara Chalk
  (Upper Cretaceous).  Uppermost beds
  (0.8 to 3 ft).
Middle beds; sample excludes four beds
  (V to 6" each) of chalky shale within
  this unit.
Lower beds (the base of the Ft. Hays).  Sample
  excludes three beds (3" to 6" thick) of
  calcareous shale within this unit.
                                                                                                                                                 i
7215
7216C
33
6-10
Caliche, sandy
S iltstone,
  calcareous
Outcrop west side of Rt. 1^7, 3 mi S of
  dam of Cedar Bluff Res., SE^ Sec. 14,
  15S-22W, Trego Co., KS.

Outcrop south side of North Fork Smoky
  Hill River on Garvey Ranch, 15 mi N
  and 5 mi E of Wallace, KS, NE-| NEij
  Sec. 11, 11S-38W, Wallace Co., KS.
 The beds below are inaccessible but belong to the
 same geologic unit and are thought to have properties
 similar to those of the sampled beds.
                                                                                                   Ogallala Formation (Pliocene]
Ogallala Formation (Pliocene).  Small
  exposure.

-------
                                                              APPENDIX  2, continued
Location and
   sample
   number
 Thickness
represented
   (ft)
                                 Type
                                                Source  and  location
                                           (quadrangle  map  in parentheses)
                                                                                  Remarks  on  the deposit
                                                                                 and geologic unit sampled
7217
              8-12
             Marl, diatomaceous
7218
7219
35
25-30
7220
7221A



722 IB


7222A

7222B
15-25
15-35
Caliche
Limestone, chalky
             Limestone,  chalky
Chalk (buff)



Chalk (gray)


Chalk (buff)

Chalk (gray)
                                                       Delore  Div.,  NL  Industries  quarry, south
                                                         side  of North  Pork Smoky  Hill River,  15
                                                         mi N  and 4  mi  E  of Wallace,  KS, SE£,
                                                         Sec.  11, 11S-38W,  Wallace Co., KS.

                                                       Texas Highway Dept.  quarry, Herndon
                                                         Quarry, 16  mi  S  of Perryton, TX, on
                                                         Rt. 83, Ochiltree  Co.,  TX.

                                                       Outcrop in bluff along Walnut  Creek £ mi
                                                         SE of Jet,  with  Dessau-Austin Rd., 7.5
                                                         mi NE of Austin, Travis Co., TX.
                        Outcrop in bluff of Walnut Creek,  \ mi
                          W of Jet.  with Interstate 35,  8  mi NE
                          of center of Austin,  Travis  Co., TX.
                                                       Universal  Atlas  Cement  Co.  quarry,  1.5
                                                         mi SW of Woodway,  Ellis Co., TX.
                                     Gifford-Hill  Portland  Cement  Co.  quarry,
                                       located 2.5 mi  N  of  Midlothian, TX,  on
                                       old  Rt. 67  and  0.5 mi W,  Ellis  Co.,  TX.
                                                                        Ogallala Formation  (Pliocene).  Source of
                                                                          raw material for Delore Div. plant located
                                                                          in Edson, KS.
                                                                                      Ogallala Formation (Pliocene).  Hard and
                                                                                        soft beds (1 to 3 ft) are crushed for use
                                                                                        in road construction.

                                                                                      Dessau Mbr. of Austin Chalk (Upper Cretaceous).
                                                                                        Weathered outcrop beds of chalk, 2 to 3 ft   |
                                                                                        thick, separated by 0.5 to 1 ft beds of      H
                                                                                                                                     I—i
                                                                                        shaley chalk.                                ro
                                                                                                                                     I
                                                                                      "Jonah Chalk" Mbr. of Austin Chalk (Upper
                                                                                        Cretaceous).  Moderately dense and nodular
                                                                                        limestone beds 2 to 3 ft thick separated
                                                                                        by chalk beds 0.6 to 1,5 ft thick.
                                                                                        Underlies Dessau Chalk at this exposure.

                                                                                      Atco Chalk Mbr. of Austin Chalk (Upper
                                                                                        Cretaceous).  Buff chalk beds 1 to 3 ft
                                                                                        thick separated by 0.5" shale partings and
                                                                                        occasional 3" to 6" calcareous shale beds.
                                                                                      Gray chalk, underlies the buff chalk (7221A).
                                                                                        Thickness of chalk quarried is 10 to 50 ft.

                                                                                      Atco Chalk Mbr. of Austin Chalk (Upper
                                                                                        Cretaceous).  Buff chalk occurs in upper
                                                                                        beds and along vertical joints.  Lower beds
                                                                                        are gray chalk.  Lowermost bed contains
                                                                                        black phosphatic nodules, 1 - 3 mm diameter.

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7223
5*
Limestone, chalky
722U
7225
7226A
7227B
7228
2.5*
30-35
4-0-45
20
                           Chalk
                           Chalk
             Chalk
                           Chalk
             Chalk
Outcrop on property of Texas Lime Co.,
  Cleburne, TX,  located at base of bluff
  on south side  of road 1 mi S of State
  Park and 13 mi SW of Cleburne, Johnson
  Co., TX.

Prospect pit, east side of farm road,
  2 mi N and \ mi W of Roxton, Lamar
  Co., TX.

Abandoned quarry at Jet. of Rts. llU and
  82 on east side of Clarksville, Red
  River Co., TX.

Arkansas Cement  Corp. quarry, 3 mi SW of
  Porman, Little River Co., AR.

Ideal Cement Co. quarry, \ mi NW of Okay,
  Howard Co., AR.

Outcrop east side of Rt. 4-, 3 mi N of
  Washington, Hempstead Co., AR.
Comanche Peak Limestone (Lower Cretaceous).
  Chalky limestone with 2" to 3" nodules  of
  dense limestone abundant throughout this
  exposure.  The base of the limestone unit
  is covered.

Gober Chalk Mbr, of Austin Chalk (Upper
  Cretaceous).  Sample from stockpile.
                                                                        Pecan Gap Chalk (Upper  Cretaceous).
                                                                          Quarry pit is filled  with water.   Upper-
                                                                          most beds  sampled.

                                                                        Annona Chalk (Upper  Cretaceous).
                                                                          Quarried by ripping.

                                                                        Annona Chalk (Upper  Cretaceous).
                                                                        Saratoga Chalk (Upper  Cretaceous).
                                                                          Weathered buff chalk.   Gray  thin-bedded
                                                                          chalk 10 to 16 ft  thick overlies  the buff
                                                                          chalk beds sampled.   Phosphatic and clayey
                                                                          chalk beds (1-2 ft thick)  and  claystone
                                                                          beds  of the Marlbrook Marl underlie the
                                                                          beds  sampled.
                                                                                                                                                 H
                                                                                                                                                 U)
  The beds below are inaccessible but belong to the
  same geologic unit and are thought to have properties
  similar to those of the sampled beds.

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                                                                  APPENDIX  2,  continued
Location and
   sample
   number
 Thickness
represented
   (ft)
                   Type
           Source and location
      (quadrangle map in parentheses)
           Remarks on the deposit
          and geologic unit sample
    7229A
    7229B
    7229C
    7229D
    7229E
    7229F

    7230
1
1
1.3

15-18
               Limestone, chalky
               Siltstone
               Limestone, chalky
               Limestone, chalky
               Limestone, chalky
               Limestone, chalky

               Chalk
                                     Outcrop east  side  of Rt.  61 at Jot.  with
                                       Bypass 6l on north edge of Vlcksburg,
                                       Warren Co., MS
Mississippi Dept. Agriculture and Commerce
  quarry located east side of Rt. 47,
  8 mi S of Trebloc in Clay Co., MS.
Byram Formation, Vicksburg Or.  (Oligocene).
  Sample A is from the uppermost bedrock
  strata; F is near the base of'exposure.
Glendon Limestone Mbr. of Byram Fin.,
  Vicksburg Gr.  Sample B underlies A,  C
  underlies B, etc.  Vicksburg Gr. limestones
  and marls are used for cement raw materials
  at nearby Redwood, MS  (Miss. Valley
  Portland Cement Co.).

Demopolis Chalk (upper part), Selma Group
  (Upper Cretaceous).  Quarried by ripping.
I
H

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