Rates of modern sedimentary processes in Lydonia Canyon off southern New England

Conference · Fri May 01 04:00:00 EDT 1987 · AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)

OSTI ID:6464264

Bothner, M H; Parmenter, C M; Rendigs, R R; Rubin, M

A 2-year study of Lydonia Canyon and the adjacent shelf and slope provided new evidence that the canyon is actively accumulating material derived from the continental shelf. /sup 14/C dates of cores collected in the heat of the canyon indicate that silty sand originating from Georges Bank has been accumulating at a uniform rate of about 60 cm/1000 years (2 g/m/sup 2//day) for the past 7000 years. Modern transport of material from the shelf to the canyon is also inferred from an increase in barium concentration of resuspended sediment from the canyon axis. The increase is coincident with the period when barium-rich drilling muds were discharged during exploratory drilling on Georges Bank. Material entering Lydonia Canyon is resuspended many times before it is permanently deposited. The flux of resuspended sediment collected in sediment traps 5 m above bottom in the canyon axis (300-m water depth) averaged 80 g/m/sup 2//day - a rate approximately 5 times higher than on the continental slope. Compared with areas outside the canyon, the more intense resuspension of sediments in the canyon axis can cause greater scavenging of sediment-reactive contaminants from the water column. This hypothesis is supported by inventories of /sup 210/Pb and /sup 239,240/Pu measured in bottom sediments, which are about 2.5 times higher in the canyon axis than on the continental slope. Discharges of hazardous wastes on the outer continental shelf may cause greater stress to benthic organisms in canyons than to those on the continental shelf or slope.

• Research Organization: Geological Survey, Woods Hole, MA
• OSTI ID: 6464264
• Report Number(s): CONF-870606-
• Conference Information: Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Journal Volume: 71:5
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100* -- Geology & Hydrology-- (-1989)
ATLANTIC OCEAN
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON 14
CARBON ISOTOPES
CONTINENTAL MARGIN
CONTINENTAL SHELF
CONTINENTAL SLOPE
EVEN-EVEN NUCLEI
GEOLOGIC HISTORY
ISOTOPES
LIGHT NUCLEI
NUCLEI
RADIOISOTOPES
SEAS
SEDIMENTATION
SURFACE WATERS
YEARS LIVING RADIOISOTOPES