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Sea-floor geology of Long Island Sound north of Duck Pond Point, New York

Open-File Report 2011-1149

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Abstract

The U.S. Geological Survey, the National Oceanic and Atmospheric Administration (NOAA), and the Connecticut Department of Environmental Protection are mapping the sea floor in coastal areas of the northeastern United States. As part of the project, more than 100 square kilometers of multibeam-echosounder data, 23 sediment samples, bottom video, and 86 still photographs were obtained from an area in Long Island Sound north of Duck Pond Point, New York, in the study area of NOAA survey H11999. This report delineates the sediment types and sea-floor features found within this area in order to better understand the sea-floor processes occurring in this part of Long Island Sound. The sea floor in the study area is dominated by ubiquitous sand-wave fields and three northeast-southwest trending bathymetric depressions. Barchanoid and transverse sand waves, including sinusoidal, bifurcating, arced, and straight-crested morphologies, are variably present. Asymmetrical sand-wave profiles indicate a westward to southwestward direction of sediment transport in most of the study area; current ripples and megaripples on the stoss slopes of the sand waves indicate transport is ongoing. The majority of the sediment on the sea floor is sand, although bouldery, gravelly, and muddy sediments are also present. Gray, cohesive mud crops out on the walls of some of the scour depressions associated with the troughs of large sand waves. Clasts of the muddy sediment scattered on the sea floor around the depressions demonstrate the intensity of the scour and suggest erosion of the underlying distal deltaic sediments.

Geospatial Extents

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Sea-floor geology of Long Island Sound north of Duck Pond Point, New York
Series title:
Open-File Report
Series number:
2011-1149
Year Published:
2012
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Woods Hole Coastal and Marine Science Center
Description:
DVD-ROM; Also available online
Country:
United States
State:
New York
Other Geospatial:
Long Island Sound