&EPA
United States
Environmental Protection
Agency
Office of
Radiation. Programs
Washington, DC 20460
EPA 520/1-83-017
June 1983
Radiation
1978 Atlantic 3800-Meter
Radioactive Waste
Disposal Site Survey:
Sedimentary,
Micromorphologic and
Geophysical Analyses
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EPA REVIEW NOTICE
This report has been reviewed by the Office of Radiation Programs,
U.S. Environmental Protection Agency (EPA) and approved for publication.
Approval does not signify that the contents necessarily reflect the
viex
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EPA 520/1-83-017
1978 ATLANTIC 3800-METER RADIOACTIVE WASTE DISPOSAl SITE SURVEY'
SEDIMENTARY, MICROMORPHOLOGIC AND GEOPHYSICAL ANALYSES
David H. Hanselman and William B. F. Ryan
Lamont-Doherty Geological Observatory
of Columbia University
Palisades, New York 10964
Prepared June 1979
Revised June 1983
This report was prepared as an account of work sponsored
by the Environmental Protection Agency of the United States
Government under Contract No. 68-01-483(5
Project Officer
Robert S. Dyer
Analysis and Support Division
Office of Radiation Programs
U.S. Environmental Protection Agency
Washington, D.C. 20460
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FOREWORD
In response to the mandate of Public Law 92-532, The Marine
Protection Research and Sanctuaries Act of 1972, as amended, the
Environmental Protection Agency (EPA) has developed a program to
promulgate regulations and criteria to control the ocean fisposal of
radioactive_ wastes. As part of that program, the EPA Office of Radiation
Programs initiated feasibility studies in 1974 to learn whether present
Cbe ^ °f -^active wastes
In 1978, the advanced technologies represented by the manned
-e.pogr.phic
! The present report provides a detailed description of the geological
and topographical characteristics of the site. Two dives were made in
Sosits8 S«1U , ^'^.radioactive waste dumpsite. The sediment
deposits, bottom topography, biota, currents, and the differences in
these parameters between the two areas within the dumpsite are discussed
The appearance of radioactive waste drums found in the dumpsite area is
analyzed in terms of the localized geological and physical Vocess^
s^biSy oThrC°nClUdeS ^ ' ^ ussion of
s tisu
Division, Office of Radiation Programs (ANR-461), Environmental
Protection Agency, Washington, D.C. 20460.
Len L. S job lorn,
Office of Radiation Programs
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ABSTRACT
Five dives with the DSRV ALVIN in the extension of the Hudson Canyon Channel
on the continental rise off Long Island were undertaken to investigate the
physical, biological and chemical environment of an area formerly utilized as
a radioactive waste disposal area. Observations within a depth range of
3985-3830 m revealed angular blocks and piles of displaced channel wall rock,
boulder and cobble olistoliths of Eocene-age chalks derived from higher
elevations on the slope, and bedforms such as ripples and scour marks which
imply the existence of periodic strong currents. Local benthic fauna are
sparse; bioturbation and burrows are uncommon. Three waste drums were located
and one was subsequently recovered for analyses. Photographic and visual
evidence suggest that downslope transport of objects such as talus blocks,
olistoliths and waste drums has occurred in this area.
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TABLE OF CONTENTS
Page
INTRODUCTION [[[ I
DIVE DESCRIPTIONS ............................................... 6
Dive 812 [[[ 6
! Dive 813 [[[ 12
RADIOACTIVE WASTE DRUM SITE AT 3970 METERS DEPTH ......................... 18
Description of Site ............................................. 18
Coring Program and Field Description of Cores .......... ............. 24
INTERPRETATION AND DISCUSSION ....................................... 26
CONCLUSIONS AND RECOMMENDATIONS .......................................... 31
LIST OF TABLES
I. Summary of samples taken during ALVIN Dives 679, 812 and 813 ........ 5
LIST OF FIGURES
I
1. I Regional bathymetric map of the continental shelf, slope and
rise seaward of Long Island, New York ................. ............. 2
2. Bathymetry of the 3800-meter Radioactive Waste Disposal Site ........ 3
3. Detailed bathymetry in the vicinity of the 1978 ALVIN dives ......... 4
4. Light tan marl or claystone angular talus blocks .................... 7
5. Outcrop of semiconsolidated tan marl or claystone ................... 8
6. : Heavily bored, white Eocene (?) chalk boulder with a
i prominent scour moat exposing a gravel bottom ....... . ............. 11
7. Gravel and cobbl e bottom ............................................ 14
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LIST OF FIGURES (Continued)
10. Rounded chalk boulder 2-3 meters long, setting on a hard
gravel bottom that is exposed in a prominent scour moat I/
11. Photograph of the first drum located during Dive 813 19
12. Photograph of first drum located on Dive 813 20
13. Position and field descriptions of tube cores taken
down-current from second drum located (#953) 22
14. Photograph of second drum (953) located 23
15. Conical rock pile near drum 953 25
16. Hypothetical model for large scale slumps as a
canyon filling mechanism
17. Stratigraphy and-seismic reflection profile for DSDP Site 106 30
18. Seismic lines showing probable positions of
Eocene and Miocene horizons at dump site -^
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INTRODUCTION
, During the period July 22 to 28, 1978, a series of five dives with the
DSRV ALVIN was made at the Atlantic 3800 meter Radioactive Waste Disposal Site.
This site is located about 380 km off the coast of Long Island on the lower
continental rise, 260 km seaward of the edge of the continental shelf, near the
main! channel of the Hudson submarine canyon system (Fig. 1). The waste
consists of approximately 15,000 55-gallon drums that are filled with low-level
radioactive waste and concrete. These are distributed over an area of a few
tens: of square kilometers in water depths of 3700 to 4100 m. The purpose of
the diving program was to study the physical, chemical and geologic setting of
the disposal site and the local biological conditions of the substrate in order
to better assess the feasibility of future disposal of radioactive waste in the
ocean.
The study was conducted in an area bounded by coordinates 37°40'N to
38°10'N and 70°24'W to 70°40'W, covering an area on the lower continental rise
near the confluence of the main channels of the Hudson and Block submarine
canyon systems (Fig. 2). In this region, the channel of the Hudson Canyon is
characterized by an approximately 1 km wide canyon floor that contains a
narrow, deeper, meandering thalweg or axis. The walls that bound the canyon
floor exhibit slopes from gentle gradients of a few degrees to vertical and
stand as high as 200 m (Fig. 3).
The primary mission of the project was to locate radioactive waste drums
and to identify and recover a suitable drum for laboratory analysis. Secondary
goal's were to take sediment and water samples near the recovered drum. The
geological work consisted of a description of bottom topography and sediments,
the nature of bedrock exposures, and the sedimentary and erosional processes,
including bioturbation, that affect the stability of the substrate. Geological
samples were taken for laboratory analysis. Selected samples are listed and
described in Table I and in Figure 13. The presentation and interpretation of
these data are the basis of this report.
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73'
72'
73'
72°
37°
70"
Figure 1
Regional bathymetric map of the continental shelf, slope and rise seaward of
Long Island, New York. A star marks the 1978 dive positions within the 3800
meter Radioactive Waste Disposal Site, enlarged as text Figure 2. Stratigraphic
control for the area is provided by the COST B-2 well, drilled in 1976 to a
depth of approximately 5000 m. Contours in meters.
O
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I
Co
I
CONTOURS IN METERS °
Fig. 2
Bathymetry of the 3800 meter Radioactive Waste Disposal Site, contoured in uncorrected meters (750 m = 1 sec. two-way
reflection time). Solid line A indicates ship's track of the R/V Vema during seismic reflection (airgun) survey. Solid line B
indicates locations of seismic reflection profile illustrated in Figure 18. Thin dashed lines are echosounding tracks of R/V Lulu.
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CONTOURS IN METERS
Figure 3
Detailed bathymetry in the vicinity of the 1978 ALVIN dives. Contour interval
is 25 m. Dives 812 and 813 explored the eastern wall of Hudson Channel.
Dive 814 surveyed and recovered a waste drum within the small circled region.
Dashed lines are survey tracks of R/V Lulu.
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TABLE I
Sample #
Alvin 812
Ski ,
Description
Sandy mud
Setting Species *
Ski Cyclococcolithus leptoporus
sample Coccolithus pelaqious
Helicopontosphaera kamptneri
Helicopontosphaera inversa
Rhabdosphaera clavigera
Coccolithus doronocoxdes
Gephyrocapsa sp.
Thoraco'sphaera sp.
Discoaster brouweri
Discoaster asymmetrioas
Age
Pleistocene
Alvin 813
Ski-1 i
Alvin 813
Ski 2
i
Alvin 8l3
Chalk >
Greyish-tan mud
w/iron staining
non-calcareous
Mud
white, consoli-
dated chalk
Ski
sample
Ski
sample
Rounded
boulder
Alvin 815
Ski :
Mud
Ski
sample
Barren
No age determination
possible
Same as in 812-ski
Chiasmolithus solitus
Zyqrhablithus bijugatus
Cyclicargolithus floridanus
Sphenolxthus moriformis
Sphenolithus radians
Discoaster barbadiensis
Braarudosphaera rosa
Similar as in 812-ski and
813-ski 2
Rare Emiliania huxleyi
Pleistocene
Eocene, probably
mid Eocene
Holocene(?)
Quaternary
Alvin 679
White chalk
collected in
1976
Boulder Cyclicargolithus florida mis
Chiasmolibus expansus
Chiasmolithus solitus
Discoaster barbadiensis
Discoaster deflandrei
Coccolithus pelagicus
Zygrhab1ithus bijugatus
Reticulofenestra umbilica
Sphenolithus radians
Helicopontosphaera seminuJ.um
Chiasmolithus gigas (?)
Braarudosphaera bigelowi
Braarudosphaera discula
Zygolithus dubius
Discolithus cf. segmenta
Tribrachiatua orthostylus
Upper Middle
Eocene
312-Core #1 Near Core #10
812-Core#10 Core taken into
scarp face near
! bottom of face
Core not available
Core not available
813-Core #2 Corrosion product Core not available
near first drum
813-Core #3 Taken in sediment Core not available
build up downcur-
rent from first
drum, 8 cm long
*Species identification by Gretchen Blechschmidt, L-DGO
-5-
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DIVE DESCRIPTIONS
Dive 812
Dive 812 on June 23, 1978, touched down at 1241 hours at a depth of 3924 m
(Fig. 3). The submersible ALVIN then slid down a 10-30 degree mud slope to a
depth of 3958 m. According to preliminary bathymetric mapping (Fig. 3) ALVIN's
deepest position during this dive (3958 m) coincided with the base of the east
wall of the Hudson Canyon channel. From this point an upslope traverse was
initiated first in a northeasterly direction and later in a southeasterly
direction. ALVIN left the bottom at a time of 1746 and a depth of 3827 m. No
radioactive waste drums were located during this dive but many interesting and
important geological observations were made.
The bottom topography around 3958 m is quite variable with slopes ranging
from 0 to 20 degrees. Small angular mud-blocks lie on the sea bed and appear
to have been derived from upslope sites (Fig. 4). Feeding trails and current
lineations are common. The bottom here could best be described as blocky and
lumpy.
Between 3950 and 3925 m, along the wall of the channel, small fluidized
sediment flows were initiated by the submersible1s contact with the sea bed.
The associated mud clouds moved downslope at a rate estimated to be about
125 to 300 cm/second. The water was turbid and the visibility was poor.
Southwesterly flowing bottom currents were persistent in the channel wall
region as well as down in the channel floor. The velocity of the currents
was estimated at about 25 cm/second. Such cross-channel flow is not unusual
in submarine canyons (see Shepard, et al., 1979) and the presence of such
currents and associated turbidity in the Hudson channel is attributed to
flow associated with the Western Boundary Undercurrent (Heezen and Hoi lister,
1971; Eittreim and Ewing, 1972). In regions of smooth topography along the
channel wall, a light tan sediment layer about 1 to 5 cm thick covers a firm,
light tan, semi consolidated marl or clay. Five to ten meter high marl or
clay scarps are present (Fig. 5). These are separated by flat areas or
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Figure 4
3830 m. Light tan marl or claystone angular talus blocks. These blocks appear
to be locally derived by the slumping of adjacent wall rock. Planar surfaces
are;interpreted as joints produced in semiconsolidated strata. In this and
other bottom photography the scale is approximately 2-3 m for the lower border
of each frame.
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1 fill!!:ii:!;ll!!T " ,,' Ji' "
kllii'jiiiiilliilljSir ijiiiililij^ , '«' i"'1iii'i»iiii,i:i' " ''" ' :i , ",' ' , ,,":,:, "" :',;/' '^''!'MI«IVV;;^
'"'HI'"[!!' I".!!!!:1'11':! i '"'»" n 'is"!'"';'"
',:, '^r\r:'"* .'.,
. . V ... ., y*g
... , ...I' ': n I/Ml »
' ir-V'j^'
llljll^^
? L*:A.:".:J::":'»:"-' :.:"*-.;.."-:'«::' "*«*:.:;:
in,,,, !'. l!*1' ,., int ^SfcufSili*';'' ,,,;.,:,n,iii i^i,,,,; ; « i.,.ma,,!, ',**=--ji
",illuy; ',;,/," Hi/ 'ii'.iii'jiliaiiiHiiiii1' i"! ,':"*iii!i!i'"l'i iiiii',,1'1''1 jiikJinil:!!! ""iiG*",;.''': ''"i'Sfililli!.11'":!, tfSS .IT1!!1'1'1!!!!,
IIIH".!!""'!!!^*!:!!^!
st-T'M
, iiMji.
Figure 5
3870 m.' Outcrop of semi consolidated tan marl or claystone. This is a small
slump scarp, bedding is indicated by horizontal ledge on left. This scarp is
about 3 m high and is typical of the entire channel wall area. The flat bench
begins at base of outcrop.
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benches. Sediment ripples with a 10 cm wavelength are present on the current-
swept flats. A possible boulder slide mark was observed and appeared to be
very recent. In this region on the lower channel wall, a sparse brittle star
population was observed along with plant debris and a few horizontal burrows.
1
; From 3925 to 3900 m, further up the channel wall, small outcrops of soft,
semiconsolidated marl or claystone were frequently observed. The outcrops
have vertical faces 1 to 3 m in height, and are separated by flat current-swept
benches. Symmetrical ripples with 15 to 20 cm wavelengths are present,
suggesting the presence of oscillatory flow at this site. The flat bench areas
often exhibit elongate tensional cracks, suggesting that the steep faces of the
outcrops may have had their origin by slumping and thus the steep faces may
represent slump scars. Subparallel crenulations just below the thin sediment
drape suggest creep phenomena that may precede or be associated with slumping.
In this depth interval, the brittle stars and the number of burrowers was seen
1
to increase but the significance of this observation is not. known.
! Most of the outcrop faces between 3900 and 3875 m are covered with a thin
sediment drape, but because of variable resistance to submarine weathering,
layering or bedding is apparent beneath the cover (Fig. 5). Beds of marl or
claystone are flaggy to massive, ranging from 10 to 30 cm thick. Occasional
cut land fill structures are present. Ripples are again present at this depth
and occur on the flat benches. A few ripples displaying wavelengths of 10 to
20 cm are oriented parallel to the slope and are also of symmetrical form. A
small slump was observed in action, probably initiated by the ALVIN.
| Similar scarp and bench topography occurs from 3875 to 3850 m. Lineations
trend downslope on the faces of some of the marl or claystone outcrops. These
appear to have been caused by small talus blocks sliding downslope. Numerous
smal;l to large angular talus blocks that appear to have fallen from higher
outcrops litter the flat areas between scarps. Many of the talus blocks are
I
plate-like slabs of marl that appear to have slid downslope, possibly on a mud
or water cushion. These flat slabs are about 10 to 50 cm in diameter and
several cm thick. Larger angular slumped blocks are also present. These vary
-9-
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greatly in size and are often bounded by smooth faces that may be joint planes
(Fig. 4). Tool marks, believed to have been formed by small pebbles sliding
downslope, are present in areas where the bottom is smooth but sloping. In
this depth interval (3875-3850 m), so many of the scarp and bench features
were observed that it is possible that this whole area is part of a very large
slump complex. The small scarps and benches are believed to have formed as
small dislocations and pullaparts and are the surface expression of much larger
scale sliding and slumping along more extensive fault planes at depth (Fig. 5).
The largest slump scarp observed was about 15 m in height and dipped 45 to
60 degrees. Angular talus blocks were present at the base of'the scarp. As
the submersible slid down the face of the scarp, observers noted that the
plates and slabs of rock lying on the scarp itself seemed to be in a state of
creep or instability. Scarps 1 to 5 m in height are the most common. Steep to
vertical angles are the rule for the scarp faces and a smoothed 20-45 degree
slope at the base of the scarps is common. A rough estimate of the spacing
between scarps or the width of intervening benches is about 5 to 20 m. The
scarps often seem to die out laterally. Aim high scarp, for instance, might
decrease in height until it blends into a gentle slope over a distance of
approximately 20 m. The megafauna between 3875 and 3850 m are generally sparse
and there is a lack of burrowing activity. This region appears to be a
biologically impoverished environment with only occasional ripples and a smooth
to dimpled bottom.
The upper part of the channel wall from 3850 to 3828 m still exhibits
slump features but the benches between slump scarps are wider and there is a
general reduction in the average slope. A small basin-like feature occurs at
about 3830 m and appears to be a bowl-shaped depression open on the downslope
side (Fig. 6). ALVIN then slid down the wall which was about 10 m high and was
covered with a light sediment drape. Currents appear to be stronger at this
depth as evidenced by the formation of elongate sediment tails downcurrent from
vertical burrows. These small sediment accumulations are dune-shaped, and are,
on the average, 10 to 30 cm in length, 5 to 8 cm wide, and 2 to 4 cm in height.
Long thin current lineations (grooves) are also present. Patches of pebbles
and plant material of unknown origin are exposed in areas where the current has
-10-
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Figure 6
3964 m. Heavily bored, white Eocene (?) chalk boulder with a prominent scour
moat exposing a gravel bottom.
-11-
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swept away the top layer of sediment. Empty snail and clam shells are present
but not abundant. The visibility is poor at these depths, 3 to 5 m being
typical. Animal life is generally sparse along the canyon wall between 3850
and 3828 m. Brittle stars occur sporadically and increase slightly upslope.
Occasional sea pens, sea whips, sponges, bryozoans, and ear-shaped sponges or
Coelenterates form the rest of the sessile fauna. Cigar-shaped hollow tubes
with an opening on one end were quite common on the bottom at depths of about
3850 m. Possibly these represent some kind of discarded egg case or molt.
Occasional rattail fish and red shrimp are present but are not common. Small
tan crabs occur on outcrops toward the upper part of the wall. Long sinuous
horizontal burrows with impressive downcurrent dune-shaped sediment mounds are
common where the currents are stronger. Small conical mounds are more common
toward the upper part of the canyon wall.
At 3828 m, the shallowest point during this dive, brown talus blocks 30 by
15 by 3 cm were observed that were similar in appearance to brown siltstone
lithologies observed in New England submarine canyons during previous dives
(Ryan et a!., 1978). Before terminating this dive, a short core (Core #10) was
taken from the base of a small fault scarp. Another short core was taken for
radioisotope analysis (Core #1). See Table I for core descriptions. All of
the sediment encountered and cored during this dive was soft to semi consolidated
as compared to the abundance of hard rock encountered on the next day, June 24,
1978.
Dive 813
ALVIN dive 813 on,June 24, 1978, in the same general area as Dive 812
(Fig. 3), reached bottom at 1305 hours at a depth of 3985 m. ALVIN touched
down on a relatively flat terrain on the floor of the Hudson Canyon channel
(Fig. 3). A 700 m long traverse was made in an easterly direction in search of
waste drums. The course followed the break in slope between the generally flat
floor of the canyon and a relatively steep (20 degrees to vertical) canyon wall.
Radioactive waste drums were located at a depth of 3970 m and the dive was
terminated from this depth at a time of 1733 hours.
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j Bottom topography in the region of this dive is characterized by irregular,
boulder-strewn and hummocky areas separated by broad flat areas. This region
is being swept by southwest-flowing currents similar to currents noted during
Dive 812. The water was turbid but slightly clearer than the water higher on
thei channel wall. Slumped blocks of all sizes and shapes litter the bottom but
seem to be concentrated in groups and piles (Fig. 7). These are separated by
featureless broad flat areas that are 30 to 50 meters wide. The blocks and
boulders can be grouped into three distinct classes. (1) Rounded cobbles and
boulders of hard crystalline rock are common. These have been carried into
deeper water by ice-rafting and have probably undergone some later concentration
in the submarine canyon system. Quartzite, granitic and metamorphic rocks
probably make up the bulk of these glacially derived cobbles (Fig. 8). (2) The
most common pebble and cobble lithology is a soft tan marl or claystone. Tan
mar,! blocks are very abundant and often occur in piles (Fig. 8). The blocks are
very angular and seem to have been shaped by intersecting joint planes. These
pilbs of blocks appear to be fresh and are generally not coated with sediment.
Based on these observations and those of Dive 812, these blocks are interpreted
to have been locally derived by slumping and sliding of semiconsolidated
sediment from further up the canyon wall. Therefore, local gravitational
instability along the canyon walls could easily explain the origin of this type
of jtalus. (3) Rounded pebbles, cobbles and boulders of white chalk are abundant
together with lesser occurrences of what appear to be blocks of brown siltstone.
One boulder of apparently interbedded white chalk and probable brown siltstone
was; observed (Fig. 9). The average size of the white chalk boulders is smaller
than the softer marl talus blocks, but 2-3 m diameter blocks were observed
(Fig. 10). The chalk blocks exhibit a variety of shapes and sizes, but equant
to Cylindrical and tabular shapes are the most common. Relatively smooth
surfaces are most common but some blocks, especially the larger boulders, are
heayily bored (Fig. 6). Burrows are subparallel and probably occur parallel to
original bedding in these rocks. The bored fabric appears to be a relict
feature, and may have taken place in a different setting. The white chalk
blocks look foreign to this environment, particularly since none of these were
observed further up the channel wall during Dive 812, although blocks of the
softer tan marl were common. The white chalk does not occur in the wall
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Figure 7
3960 m. Gravel and cobble bottom. Quartz pebbles with manganese coatings.
White Eocene (?) chalk cobble protrudes from bottom at right center. Rounded
marl or claystone talus is derived from the wall on the left.
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Figure 8
3967 m. Gravel and mud bottom. Currents in this region are 25 to 30 cm/sec.
Rounded cobble in foreground is glacially derived. White Eocene (?) chalk
boulder in background is believed to represent slumped material derived from
exposures farther up the Hudson canyon or from the adjacent slope. Soft marl
or claystone talus is derived from wall at left corner.
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Figure 9
3960 m. Semiconsolidated marl or claystone talus derived from the wall at
right front of photograph. White chalk and brown siltstone (?) boulder at
center is embedded in soft marl or claystone. This material is thought to be
derived from exposures at shallower depths in the canyon or on the slope.
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! Figure 10
39^1 m. Rounded chalk boulder 2-3 m long, resting upon a hard gravel bottom
that is exposed in a prominent scour moat. Such excavations and the general
absence of sediment dusting on boulders implies fairly strong and recent
current activity at the site.
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exposures either as bedded deposits or as resedimented clasts. The white chalk
blocks were probably derived from further up the continental slope where
similar rocks have been observed in place (Heezen and Dyer, 1977; Ryan et al.,
1978; Musick, pers. comm., 1978). A sample of this rock type was collected at
the drum recovery site and was determined to be of mid-Eocene age based on its
contained microfauna (Table I). A sample of the same lithology was taken during
investigation of the 2800 m dump site (Rawson and Ryan, 1978) and has also been
dated as mid-Eocene (Sample 679, Table I). The white chalk appears to have
originally accumulated in a shallower and more landward environment in water
depths of 1500 to 2500 m (G. Blechschmidt, pers. comm.) and was redeposited
at a later date in the Hudson Canyon system as blocks, boulders, cobbles and
pebbles. Thus it is concluded that these rocks are not locally derived but
have been transported down the canyon by some type of slide or mudflow mechanism.
Scour moats are generally present around the bases of boulders in this
region of the Hudson channel. These current scours are present on the upcurrent
side of the boulders and a sediment buildup or drift is usually present on the
downcurrent side. Scour moats (Fig. 10) have a variety of sizes and shapes but
are 5 to 10 cm deep on the average. A large quartzite boulder of glacial
origin was observed that was surrounded by an impressive scour moat. An older
mud burial line was still visible on the boulder about 30 cm above the exposed
base of the boulder. This provides a good example of recent erosion.
RADIOACTIVE WASTE DRUM SITE AT 3970 METERS DEPTH
Description of Site
The first radioactive waste drum was spotted during Dive 813 at 1540 hours
and a depth of 3970 m (Fig. 11). This drum was lying on a hummocky, irregular
sea bottom. The three types of talus blocks described above surrounded the
drum. Although these blocks varied greatly in size many of them were about the
size of the drum (Fig. 11). A prominent scour moat was present on the upcurrent
side of the drum, and a mound of granule-sized sediment had been built up on
the downcurrent side of the drum (Fig. 12). The drum was intact, but highly
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: Figure 11
3970 m. Photograph of the first drum located during Dive 813. Currents
have kept the upper surface of this heavily corroded drum free of sediment
accumulation. Soft marl talus litters the local area of this drum. Corrosion
has obliterated identification markings.
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Figure 12
Photograph of first drum located on Dive 813. This drum is resting on a hard
substrate. Corrosion of the drum has streaked the sediment surface in a
downcurrent direction. The corrosion products are coming from the upper right
hand corner of the drum. Note large marl or claystone talus blocks lying about.
-20-
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corroded and blistered. Trails of corroding material were observed coming from
the, drum (Fig. 12). A core was taken in the corrosion-rich sediment and another
in |the sediment buildup on the downcurrent side of the drum (Table I). The
sediment drift consisted of foraminiferal sand. The core only penetrated about
8 cm and a hard light tan clay or marl substrate was observed. Thus the
bottom in this area does not appear to be a product of recent deposition, but
instead probably represents an erosional surface covered with a thin biogenic
or hemipelagic sediment layer (Fig. 13).
Another waste drum (No. 953) was located nearby (Fig. 14). This drum was
surrounded by a well-defined scour moat similar to that around the first drum.
One end of the drum had a wedge of sediment sloping away from it. This wedge
appears to have formed when the drum slid into its final resting position-,
plowing the sediment as it moved (Fig. 14). Various sizes,, shapes, and types
of talus were lying around drum No. 953. Abundant rounded white and brown
pebbles were present in the drum area (Fig. 7). These gravelly deposits appear
to have been sorted by currents and are exposed in patches. Elsewhere the
gravels are obscured by thin, hemipelagic surface deposits. These gravels are
probably glacial in origin and were later concentrated by currents flowing in
the canyon channel. Small white anemones were attached to larger rocks near
the drum and it is interesting to note that these organisms;, which favor hard
substrates, were absent from the drum surface. Brittle stars and a few small
i
scorpion-like crabs and large rattail fish were the dominant inhabitants of the
drum area. As noted, no organisms were observed on the drum itself. The
currents seemed to be stronger at this drum site than those of the previous
site, Dive 812. The velocity was estimated at 25 to 30 cm/sec. When the mud
bottom was disturbed by the submersible, the sediment was quickly swept away
downcurrent after a few minutes. The largest and deepest scour moats were
observed around the large talus blocks in this area (Fig. 10). The site of
this drum is characterized by a highly variable, complex depositional and
erosional topography. Thirteen sediment cores, a water sample and a box core
containing a brittle star were taken from this site for various geochemical and
radiochemical laboratory analyses (Fig. 13).
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I
CONICAL
PILE
sw
CURRENT
SCATTERED ROCKS
OF MARL AND CHALK
3970m ...j.,.v..... ..v..i-.i.....:i"^[-rC^..^
-^v?^5ls^s^-'-:^i-.-"'' 7
8+9
12+13
SED1MEN1
BUILDUP
MOAT
SEA
B01TOM'
ro
!0cm
FORAM OOZE (SAND)
WITH CLAY AND SILT
SILT
CLAY
R=RED
P=PINK
T=TAN
LT= LIGHT TAN
LB=LIGHT BROWN
G =GREY
BL=BLACK
Figure 13
Position and field descriptions of tube cores taken downcurrent from Drum 953.
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Figure 14
3970 m. Photograph of second drum (953) located. Soft mud bottom is disturbed
by ALVIN. Sediment wedge at the end of the drum may have been plowed up when
the drum slid into its present position.
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Before leaving the bottom, rock specimens were taken from a conical pile
of unsorted rubble near the drum. This rock pile is about 3 to 5 m high and
consists of rounded white cobbles and boulders of chalk, glacial cobbles and
locally derived tan marl talus blocks (Fig. 13, Fig. 15). This mound of rocks
was like others observed while searching for the waste drums. Two samples were
taken from this pile. The white cobbles (ALVIN 813 chalk) here are believed to
be representative of all the white blocks of boulder to cobble size encountered
along the bottom during Dive 813. The mode of origin of these piles is unclear
at this point. Perhaps these represent the toe of a circular slump that has
pushed this rock mixture to the surface, forming a small cone that has had-Us
fine-grained sedimentary component stripped away by recent currents.
Coring Program and Field Description of Cores
The first waste drum discovered was a 55-gallon drum. A scour moat was
present on the upcurrent side of the drum and a sediment buildup occurred on
the downcurrent side. The drum was sitting on a firm bottom as evidenced by
its lack of burial (Fig. 11). Two cores (Table I) were taken with 40 cm-long
plastic core tubes, but because of the hard bottom only a few inches of sediment
were recovered in each core. One core (Core #2) was taken in the area stained
by the corrosion from the barrel near the east corner of the drum and the other
core (Core #3) was taken in the sediment buildup on the downcurrent side of the
drum.
A series of 13 tube cores, 10 of which are discussed here, were taken at
the recovery drum site (No. 953). The 10 cores were taken at approximately
2 m intervals starting at a distance of about 14 m on the downcurrent side of
the drum (Fig. 13). These cores were to be used for various radiochemical
and geochemical analyses and only the field description made through the
plastic core tubes is available for this report. These cores sampled two
distinct lithologies, or sedimentary layers. The first layer consists of a
4 to 10 cm thick foraminiferal rich marl. The percentage of clay and silt
increases downward within this unit. This layer is soft and porous and is tan
to light brown in color. Near the drum and in the sediment buildup on the
downcurrent side of the drum a significant amount of corrosion products (rust)
-24-
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Figure 15
3970 m. Conical rock pile near drum 953. Two cobbles were sampled from this
pile. One is a glacial erratic, the other is Eocene-age chalk (Table I.)
-25-
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from the drum is mixed into this layer, creating a reddish discoloration of the
sediment (Fig. 13, Core #1). The upper layer is generally in sharp contact
with the lower layer which consists of semiconsolidated light tan, silty marl
or claystone. This layer is quite hard as evidenced by the lack of core
penetration. This layer is mottled in some of the cores and vertical burrows
exist in others. The surface sediment has filtered down into the burrows. A
pebble assumed to be quartz was noted along the contact between these two units
in Core 6 and probably represents a lag deposit formed during a period of strong
currents. Core #1 was taken at an angle under the drum to test the oxidation
state of the sediments under the drum. This core contained considerable black
colored sediment, the cause of which is uncertain but may be due to the
formation of sulfides under anoxic conditions. This was the longest core taken
from this series and was 28 cm long. Average penetration of the cores was
about 15 cm.
The contact between these two lithologic units probably represents an
erosional surface or a local unconformity. This erosional surface or
unconformity is probably still forming in some parts of the channel, while in
other parts of the channel foraminifera-rich surface sediments accumulate above
it, particularly behind rocks or other topographic obstructions that break up
the constant southwesterly current flow and possible tidal (and/or inertial)
current flow which may be present.
INTERPRETATION AND DISCUSSION
The radioactive waste dump site studied encompasses an area of a few
tens of square kilometers centered around 70°35'W to 37°50'N. According to
available records, about 15,000 55-gallon drums of low-level radioactive
waste embedded in concrete are reported to make up the contents of the dump
site (Dyer, 1976). Only three drums were located during Dives 812 and 813
and one drum (No. 953) was recovered on Dive 814. The drums located on these
dives appear to be lying near the base of the eastern side of the Hudson
submarine canyon channel on the lower continental rise at a depth of 3970 m
(Fig. 3). The main axis or thalweg of the channel appears to lie about 1 km to
-26-
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the west based on a limited bathymetric survey (Fig. 3). There is some
evidence that this deeper axis meanders across a relatively flat channel floor
(Figl 3). Where the channel thalweg hugs the channel wall, tidal and/or
contour currents may be concentrated to produce higher velocity currents than
those observed on the channel flats (15-30 cm/sec). Higher velocity currents
might cause the thalweg to cut laterally into the soft marl or claystone
bedrpck thus oversteepening the slope. Oversteepening or undercutting at the
basejof the slope would allow slumps or gravity slides to occur. Based on the
observations made during Dives 812 and 813, there seems to be little doubt that
i
this; is a region characterized by major slumping and that the oversteepening
mechpnism could account for the observed scarp and bench topography. The scale
of this slumping is difficult to assess. Small slumped blocks and scarps are
easijly observed, but larger features are difficult to assess from a submersible.
It is most probable that the smaller features observed indicate that slumping
on ajmuch larger scale is taking place (Fig. 16). These data indicate that the
canyon axis is presently being filled along its margins through the process of
slumping from the walls.
JA possible model for the earlier incision and later partial filling of the
Hudsbn Canyon channel is suggested below and illustrated in Figure 16. During
the ;last low sea level stand some 15 to 20,000 years ago, a much deeper, steep
walled canyon was cut into the deposits of the continental rise. Many previous
workers have both suggested and documented that the submarine canyons of the
continental slope were deeply incised during this period (Shepard, 1952;
Stetson, 1936, 1949). The Pleistocene age Hudson Canyon channel or seaward
extension of the Hudson Canyon may have been a deep vee-shaped valley cut or
formed by the action of sediment-laden turbidity currents or submarine debris
flows as they passed seaward through this region towards the Hudson Fan Complex.
As the Wisconsin-age glaciers receded, sea level rose and the sediment supply
to the continental shelf, slope, rise and abyssal plain was diminished. At
this time, the Hudson Canyon channel began to backfill from the seaward side.
Two possible mechanisms, operating together, could account for this backfilling:
-27-
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I
ro
CO
Figure 16
Hypothetical model for large scale slumps as a canyon filling mechanism.
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with the many documented slump scarps along the channel walls, indicate that
the channel floor is a site of net accumulation.
; If these postulated geologic processes are indeed operating in this area,
some geologic recommendations in terms of waste disposal can be made. First,
it is clear that this is a very unstable area as indicated by slump scarps,
avalanche deposits, and a lack of biological activity. Concrete filled drums,
once introduced into the canyon system might behave as any other sedimentary
particle, that is, these drums may move down the channel just as the chalk and
siltstone cobbles and boulders have moved. The barrels observed on Dive 813
were probably in their original dumped position but some evidence of movement
was indicated (plowed sediment) (Fig. 14). It is also possible that these
drums may have slid down the channel walls to their present position, which
would account for their position at the base of the channel. Any drums present
on the channel floor could be subsequently moved or buried by slides or slumps
from the channel walls which may plow into the channel area with great force.
: Many speculations and assumptions have been presented in this report, but
these are considered reasonable based on the available data. Further study is
needed to support, alter or disprove the suggested geologic processes operating
in. the lower reaches of the Hudson submarine canyon. Based on this study, this
area is classified as a dynamic deepsea environment whose agents and processes
are presently poorly understood. With respect to future, waste disposal
activities in this and other canyon environments, material dumped on the flat
divides between channels may eventually be displaced or buried if the
interpretation of successive slumping and filling of channels is correct (Fig.
16). If low-level radioactive waste material is to be dumped in the North
Atlantic, the flat and featureless abyssal plain areas to the northeast would
be a geologically more stable area to consider for the possibility of future
dumping.
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REFERENCES
3.
4.
6.
7.
8.
9.
10.
11. i
12.
Cacchione, D.A., G.T. Rowe, A. Malahoff, 1978, "Submersible Investigation
of Outer Hudson Submarine Canyon," in Stanley, D.J. and G. Kelling, eds.,
Sedimentation in Submarine Canyons, Fans, and Trenches, Dowden,
Hutchinsen & Ross, p. 42-50.
Dyer, R.S., 1976, "Environmental Surveys of Two Deepsea Radioactive Waste
Disposal Sites Using Submersibles," in Proceedings, International
Symposium on Management of Radioactive Wastes from the Nuclear Fuel Cycle,
International Atomic Energy Agency, Vienna, v. 2, p. 317-338.
Eittreim, S. and M. Ewing, 1972, "Suspended Particulate Matter in the Deep
Waters of the North American Basin," in Studies in Physical Oceanography,
A.L. Gordon, ed., Gordon & Breach, NY, v. 2, p. 123-168.
Emery, K.O. and E. Uchupi, 1972, "Western North Atlantic Ocean Topography,
Rocks, Structure, Water, Life and Sediments," Amer. Assoc. Petrol. Geol.
Mem., 17, 532 pp.
Heezen, B.C. and C.D. Hollister, 1971, The Face of the Deep, Oxford
University Press, NY, 659 pp.
Heezen, B.C. and R.S. Dyer, 1977, "Meandering Channel on the Upper
Continental Rise of New York," EOS, Transactions, American Geophysical
Union, v. 58, p. 410.
Hollister, C.D., J.I. Ewing, et al., 1972, Initial Reports of the Deep
Sea Drilling Project, v. XI, U.S. Government Printing Office, Washington,
DC, p. 313-319.
Rawson, M.D. and W.B.F. Ryan, 1978, "Geologic Observation of the Atlantic
2800-Meter Radioactive Waste Disposal Site," U.S. Environmental Protection
Agency Report 520/1-83-018, 86 p.
Ryan, W.B.F., M.B. Cita, E.L. Miller, D. Hanselman, W.D. Nesteroff,
B. Hecker, and M. Nibbelink, 1978, "Bedrock Geology in New England
Submarine Canyons," Oceanologia Acta, v. 1, p. 233-254.
Shepard, F.P., 1952, "Composite Origin of Submarine Canyons," Jour. Geology,
v. 60, p. 84-96.
Smith, M.A., R.V. Amate, M.A. Furbush, D.M. Pert, M.E. Nelson, J.S. Hendrix,
L.D. Tamm, G. Wood, Jr., and D.R. Shaw, 1976, "Geological and Operational
Summary, Cost No. B-2 Well, Baltimore Canyon Trough Area, Mid-Atlantic DCS,"
U.S. Geological Survey Open File Report 76, p. 774-779.
Stetson, H.C., 1936, "Geology and Paleontology of the Georges Bank
Canyons," Geol. Soc. Amer. Bull., v. 47, p. 339-366.
-35-
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA 520/1-83-017
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
1978 Atlantic 3800 Meter Radioactive Waste Disposal Site
Survey: Sedimentary, Micromorphologic and Geophysical
Analyses
5. REPORT DATE
June 1983
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
David H. Hanselman, Ph.D.
William B.F. Ryan, Ph.D.
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Lamont-rDoherty Geological Observatory
of Columbia University
Palisades, New York 10964
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
Contract No. 68-01-4836
12. SPONSORING AGENCY NAME AND ADDRESS
Office of Radiation Programs
U.S. Environmental Protection Agency
401-M Street, S.W.
Washington, D.C. 20460
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
ANR-461
15. SUPPLEMENTARY NOTES
16. ABSTRACT : ~~~ '
During jthe period of 22-28 July 1978, five dives were made in the manned submersible
ALVIN into the Atlantic Ocean 3800-meter depth radioactive waste disposal site located
in the [Hudson Canyon channel approximately 320 kilometers from the Maryland-Delaware
coast. | A geological description of the site was made by direct examination of the
bottom (topography, bedrock exposures, sedimentary and erosional processes, and sedi-
ment cojres collected from the dumpsite area. Observations within a depth range of
3985-38f30 meters revealed angular blocks and piles of displaced channel wall rock,
boulder; and cobble olistoliths of Eocene-age chalks derived from higher elevations on
the slope, and bedforms such as ripples and scour marks which imply the existence of
periodic strong currents. Local benthic fauna, were sparse. Three low-level radio-
active waste drums were examined from the submersible, and one was subsequently
recoverjed for corrosion and concrete deterioration analyses. Photographic and visual
evidence suggest that downslope transport of objects such as talus blocks, olistoliths
and radioactive waste drums has occurred in this area.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
ocean disposal
low-level radioactive waste disposal
deepsea geology
Hudson Canyon geology
marine foraminifera
8. DISTRIBUTION STATEMENT
I
Unlimited Release
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
b.IDENTIFIERS/OPEN ENDED TERMS
19. SECURITY CLASS (This Report)
Unclassified
2O. SECURITY CLASS (This page)
Unclassified
c. COSATI Field/Group
21. NO. OF PAGES
43
22. PRICE
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United States
Environmental Protection
Agency
Washington DC 20460
Official Business
Penalty for Private Use $300
Postage and Fees Paid
Environmental Protsction Agsncy
FPA-335
Special
Fourth-Class
Rate
Book
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