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Sea-floor geology in central Rhode Island Sound south of Sakonnet Point, Rhode Island

August 7, 2012

The U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA) are working together to study the sea floor along the northeastern coast of the United States. NOAA collected multibeam-echosounder data during hydrographic survey H11995 in a 63-square-kilometer area in central Rhode Island Sound, south of Sakonnet Point, Rhode Island. The USGS collected sediment samples, bottom video, and still photographs from 27 stations in this study area to verify an interpretation of the bathymetric data. Collected data are used to map areas of scour depressions and erosional outliers, megaripples, boulders, and relatively undisturbed modern marine sediments. In general, much of the eastern part of the study area, a submerged segment of the Harbor Hill-Roanoke Point-Charlestown-Buzzards Bay moraine, is bouldery. Bottom photography shows boulders are generally encrusted with hydrozoans, algae, and anemone. Scour depressions, presumably formed by long-period storm waves, and erosional outliers of Holocene sediments dominate the western part of the study area and several large areas in the east. The scour depressions tend to have coarser grained sediment than intervening erosional outliers. The coarseness likely creates turbulence in the water over these areas, which prevents fine-grained sediment deposition. Several small areas of megaripples are visible in the bathymetry data in the west. Other sandy areas are typically rippled, with burrows, worm tubes, and starfish present.

Publication Year 2012
Title Sea-floor geology in central Rhode Island Sound south of Sakonnet Point, Rhode Island
DOI 10.3133/ofr20121004
Authors K. Y. McMullen, L. J. Poppe, S.D. Ackerman, C.R. Worley, M.A. Nadeau, M. V. Van Hoy
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 2012-1004
Index ID ofr20121004
Record Source USGS Publications Warehouse
USGS Organization Woods Hole Coastal and Marine Science Center