43° 
BLOCK 
ISLAND 
e NANTUCKET 
MARTHA'S °. /SLAND 
VINE YARD 
x 
S 
x 
13A@a 
X39 
RS 
RS 
KR 
dS 
8 
0C140-8B = 
0C140-41 
Ss 
40° 
fee 7° 70° 69° 
EXPLANATION 
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Gato kilometers 
Bathymetry in meters 
Ga° 67° 66° 65) 
FIGURE 1A.—Regional sampling station array. Site-specific array in block 312 is centered at station 5. Triangles indicate loca- 
tions of cores analyzed during the third year of monitoring. Station 7 is within the area covered by the dot labeled 7A. 
mud) with minimal disturbance of the sediment. 
Cores containing the undisturbed water-sediment 
interface were collected in thin-walled fiberglass 
core barrels and were frozen after collection. The 
samples were later extruded, thawed, and cut into 
1-cm sections for analysis. 
Core 83G9-B was collected from the Continen- 
tal Slope (fig. 1A) by using a conventional box 
corer. A subcore was sectioned into 1-cm depth 
intervals. The depth distribution of metals also 
was determined on samples removed in 2-cm depth 
intervals from grab samples. 
In the laboratory, the samples were thawed, 
homogenized, and subsampled under a laminar 
flow hood. Aliquots from individual grabs and 
sample blends, made up of equal weights from 
the individual grabs, were separated for chemi- 
cal and textural analyses. Samples for chemical 
analyses were dried to a constant weight at 70 °C 
in an oven having teflon-coated surfaces and a 
filtered nitrogen atmosphere. Dried samples were 
ground in an agate grinder after shell or sediment 
particles larger than 2 mm were removed. Drill 
cuttings, identified by their angular edges and 
unusual color, were not removed. These samples 
are referred to as bulk sediments (undifferen- 
tiated with respect to size) throughout this 
report. 
To maximize the analytical resolution in identi- 
fying drilling mud components, sand and coarser 
material were removed from selected samples. 
Filtered distilled water was used to wash the silts 
and clays through a 60-ym nylon sieve. (A 63-um 
sieve, used to separate sand from finer material 
in the standard textural analysis procedures, was 
unavailable in a nonmetal material.) The resultant 
slurry was dried in a teflon-coated oven and then 
ground and analyzed by the same methods used 
for bulk sediments. Corrections were made for the 
weight of salt contributed by the interstitial water 
by using the following relation between chlorinity 
(Cl) and salinity (S): 
