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U.S. Geological Survey Open-File Report 02-002

Geological Framework Data from Long Island Sound, 1981-1990:

A Digital Data Release

Visual Core Description: LISAT-12

SHIP: R/V Atlantic Twin
LOCATION: Horton Point (L.I.N.Y.), eastern Long Island Sound
LATITUDE: 41o 07.7' N
LONGITUDE: 72o 28.8' W
LORAN: 26329.9, 43947.8
COMMENTS: Seismic line for this core is Line AT#10 (sparker). This lines runs from 0939-0957. hrs. Core at 0952 on record. Core through marine unconformity. Target site was I-1 on uniboom record line 30, at 1646, AST 82-3, at 1335 on 2/85). Section 4 contains a clay concretion in the archive half. Section 5 has a white quartz pebble in the working half, and a clay concretion in the archive half.
PENTROMETER RECORD: Rapid 0-18'; moderate 19-23'; slightly slower 24' to end
0-100 cm (Section 1A) - Dark olive gray, 5Y 3/2, sand, fine, silty, no layering, scattered shell fragments, shell fragments increase below 75 cm (25-32 cm: 44% sand, 47% silt, 8% clay).
100-198 cm (Section 1B) - 100-139 cm: dark olive gray 5Y 3/2, sand, fine, silty, scattered shell fragments, no layering. 139-198 cm: silty clay and clayey silt layering, shell fragments at 151-158 cm, filled burrow at 184-191, pebble at 186 cm, fine sand layers below 186 cm.
198-344 cm (Section 2) - Dark olive gray, 5Y 3/2. 198-227 cm: silt with occasional shell fragments, gradational contact at 227 cm, burrow down center of core filled with clay and shell fragments between 199-227 cm. 227-230 cm: fine sand and silt mixed with abundant shell hash. 230-245 cm: silt and fine sand mixed with lesser amounts of shell hash.245-298 cm: slight textural differences (sandy silt and clayey silt) make layering, very poorly sorted (272-280 cm: 32% sand, 53% silt, 15% clay). 298-304 cm: silt and fine sand. 304-306 cm: clayey silt layer; 306-324 cm: silty fine sand some shells; 324-344 cm: silty fine-medium sand with shell fragments.
344-494 cm (Section 3) - Dark olive gray, 5Y 3/2 sand, fine - medium, silty; shell fragments vary in density throughout section; large oyster shells at 390-394 and 400-409 cm; clayey silt layer at 368-370 cm; organic fibers at 482 and 492.5 cm.
494-649 cm (Section 4) - 494-562 cm: mottled transition zone, olive gray, 5Y 4/2 sand, fine to medium, silty, some shell fragments; grayish brown, 10YR 5/2 (looks like a red-brown to the eye) clay blebs mixed into sand, no shel fragments, sharp contacts along edges of blebs; at about 537 cm the sandy areas become blebs within the clay. 562-649 cm: clay, silty, layered (0.1 cm thick) convex upward flattening down section, sand bleb at 598-601 cm (607-615 cm: 1% sand, 32% silt, 67% clay).
649-870 cm (Section 5) - Clay, alternating layers of brown 7.5YR 5/2 and brown/dark brown, 7.5YR 4/2, brown layers are 0.3-0.4 cm thick, dark brown layers are 0.5-0.6 cm thick, layers are convex upward; rounded quartz pebbles at 723-728 cm and 732 cm (752-759 cm: 1% sand, 28% silt, 71% clay).

Department of the Interior > U.S. Geological Survey > Coastal and Marine Geology Program  > Long Island Sound Studies
Contact: L.J. Poppe (")