Long Island Sound is one of the largest estuaries along the Atlantic coast of the United States. It is a glacially produced, semi-enclosed, northeast-southwest-trending embayment, which is 150 km long and 30 km across at its widest point. Its mean water depth is approximately 24 m. The eastern end of the Sound opens to the Atlantic Ocean through several large passages between islands, whereas the western end is connected to New York Harbor through a narrow tidal strait. Long Island Sound abuts the New York-Connecticut metropolitan area and contains more than 8 million people within its watershed. A study of the modern sedimentary environments on the sea floor within the Long Island Sound estuarine system was undertaken as part of a larger research program by the U.S. Geological Survey (Coastal and Marine Geology Program) conducted in cooperation with the State of Connecticut Department of Environmental Protection and the U.S. Environmental Protection Agency. Knowledge of the bottom sedimentary environments was needed to discern the long-term fate of wastes and contaminants that have been, or potentially will be, introduced into the system and to help understand the distribution of benthic biologic habitats.

Long Island Sound is one of the largest estuaries along the Atlantic coast of the United States. It is a glacially produced, semi-enclosed, northeast-southwest-trending embayment, which is 150 km long and 30 km across at its widest point. Its mean water depth is approximately 24 m. The eastern end of the Sound opens to the Atlantic Ocean through several large passages between islands, whereas the western end is connected to New York Harbor through a narrow tidal strait. Long Island Sound abuts the New York-Connecticut metropolitan area and contains more than 8 million people within its watershed. A study of the modern sedimentary environments on the sea floor within the Long Island Sound estuarine system was undertaken as part of a larger research program by the U.S. Geological Survey (Coastal and Marine Geology Program) conducted in cooperation with the State of Connecticut Department of Environmental Protection and the U.S. Environmental Protection Agency. Knowledge of the bottom sedimentary environments was needed to discern the long-term fate of wastes and contaminants that have been, or potentially will be, introduced into the system and to help understand the distribution of benthic biologic habitats.

Many scientific questions and policy issues related to sediments in Long Island Sound require data of historical, regional and interdisciplinary scope. Existent data is often geographically clustered and its references are widely dispersed and not always accessible. Acquisition of new data is expensive and may duplicate previous efforts if a full interpretation of existent data has not occurred. Consequently, the body of existing data needs to be utilized to its maximum so that it can serve as a foundation, baseline, and starting point for further work. An accessible, documented, and simple-to-use compilation of existing data on sediment properties is essential for environmental managers, policy-makers, scientific researchers, and interested members of the public. To this end, we have compiled, edited, and integrated all of the available data on sediment texture and bottom descriptions throughout the Sound in order to produce a regional dataset which will be available to a wide variety of current and potential users. The significant feature of this textural dataset is that it comprehensively contains original data from many heterogeneous sources.

Many scientific questions and policy issues related to sediments in Long Island Sound require data of historical, regional and interdisciplinary scope. Existent data is often geographically clustered and its references are widely dispersed and not always accessible. Acquisition of new data is expensive and may duplicate previous efforts if a full interpretation of existent data has not occurred. Consequently, the body of existing data needs to be utilized to its maximum so that it can serve as a foundation, baseline, and starting point for further work. An accessible, documented, and simple-to-use compilation of existing data on sediment properties is essential for environmental managers, policy-makers, scientific researchers, and interested members of the public. To this end, we have compiled, edited, and integrated all of the available data on sediment texture and bottom descriptions throughout the Sound in order to produce a regional dataset which will be available to a wide variety of current and potential users. The significant feature of this textural dataset is that it comprehensively contains original data from many heterogeneous sources.

Many scientific questions and policy issues related to sediments in Long Island Sound require data of historical, regional and interdisciplinary scope. Existent data is often geographically clustered and its references are widely dispersed and not always accessible. Acquisition of new data is expensive and may duplicate previous efforts if a full interpretation of existent data has not occurred. Consequently, the body of existing data needs to be utilized to its maximum so that it can serve as a foundation, baseline, and starting point for further work. An accessible, documented, and simple-to-use compilation of existing data on sediment properties is essential for environmental managers, policy-makers, scientific researchers, and interested members of the public. To this end, we have compiled, edited, and integrated all of the available data on sediment texture and bottom descriptions throughout the Sound in order to produce a regional dataset which will be available to a wide variety of current and potential users. The significant feature of this textural dataset is that it comprehensively contains original data from many heterogeneous sources.

Many scientific questions and policy issues related to sediments in Long Island Sound require data of historical, regional and interdisciplinary scope. Existent data is often geographically clustered and its references are widely dispersed and not always accessible. Acquisition of new data is expensive and may duplicate previous efforts if a full interpretation of existent data has not occurred. Consequently, the body of existing data needs to be utilized to its maximum so that it can serve as a foundation, baseline, and starting point for further work. An accessible, documented, and simple-to-use compilation of existing data on sediment properties is essential for environmental managers, policy-makers, scientific researchers, and interested members of the public. To this end, we have compiled, edited, and integrated all of the available data on sediment texture and bottom descriptions throughout the Sound in order to produce a regional dataset which will be available to a wide variety of current and potential users. The significant feature of this textural dataset is that it comprehensively contains original data from many heterogeneous sources.

This GIS layer contains an computer generated model of the distribution of surficial sediments in Long Island Sound.

This GIS layer contains an computer generated model of the distribution of surficial sediments in Long Island Sound.

This CD-ROM (Compact Disk - Read Only Memory) contains sidescan sonar, high-resolution seismic-reflection, bathymetric, textural, and bibliographic data and interpretations collected, compiled, and produced through the U.S. Geological Survey/State of Connecticut Cooperative and the Long Island Sound Environmental Studies Project of the Coastal and Marine Geology Program, U.S. Geological Survey during October 1991 to August 1998. Cooperative research with the State of Connecticut was initiated in 1982. During the initial phase of this cooperative program, geologic framework studies in Long Island Sound were completed. The second and current phase of the program, which is the focus of this CD-ROM, emphasizes studies of sediment distribution, processes that control sediment distribution, near-shore environmental concerns, and the relationship of benthic communities to sea-floor geology. The study area covers all of Long Island Sound, which is bordered on the north by the rocky shoreline of Connecticut, on the east by Block Island Sound, on the south by the eroding sandy bluffs of Long Island, and on the west by the East River and the New York metropolitan area. Sidescan sonar data were variously collected with 100 kHz Klein, Datasonics, and Edgetech systems under two survey schemes. In the first scheme, the data were collected along closely-spaced grids where the ship tracks were spaced 150 m apart and the sonar system was set to sweep 100 m to either side of the ship's track. This scheme produced the continuous-coverage acoustic images that are stored on the CD-ROM as TIF files. In the second scheme, the sidescan sonar data collected along reconnaissance lines spaced about 2,400 m apart. Only selected portions of this data, when used for geologic interpretation, are stored on this CD-ROM. Under both survey schemes, the sidescan sonar data were processed according to procedures summarized by Danforth and others (1991) and Paskevich (1992a, 1992b, 1992c). The seismic reflection data were variously collected with an Ocean Research Equipment 3.5-kHz profiler transmitting at a 0.25-s repetition rate and a Datasonics CHIRP system set to sweep between 2-7 kHz. Only selected seismic-reflection data, which are used as examples in geologic interpretations, are stored as GIF-formatted images on this CD-ROM. Navigation during this project was determined with a differential Global Positioning System (GPS); position data were logged at 10-second intervals. The bathymetric data were collected by means of a 200-kHz echo sounder and logged digitally. Surficial sediment (0-2 cm below the sediment-water interface) sampling completed as part of this project was conducted using a Van Veen grab sampler equipped with an Osprey video and still camera system. The photographic system was used to appraise bottom variability around stations, faunal communities, and sedimentary processes. It also documented bedrock outcrops and boulder fields where samples could not be collected. The fine fraction (less than 62 microns) was analyzed by Coulter Counter (Shideler, 1976); the coarse fraction was analyzed by sieving (gravel) and by rapid sediment analyzer (sand; Schlee, 1966). The data were corrected for the salt content of interstitial water. Size classifications are based on the method proposed by Wentworth (1929) and were calculated using the inclusive graphics statistical method (Folk, 1974), using the nomenclature proposed by Shepard (1954). A detailed discussion of the sedimentological methods employed are given in Poppe and others (1985); a detailed description of the methods used to perform the CHN analyses are given in Poppe and others (1996) . The database presented here contains over 14,000 records and 83 fields (see the Data Dictionary below). The specific fields and parameters have been chosen based on the data produced by the sedimentation laboratory of the Coastal and Marine Geology Program of the U.S. Geological Survey in Woods Hole, Mass., and

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Bathymetry and sidescan-sonar imagery, originally collected by NOAA for charting purposes, provides a fundamental framework for research and management activities in Long Island Sound, shows the composition and terrain of the seabed, and provides information on sediment transport and benthic habitat. During October 2008 NOAA completed hydrographic survey H11997 offshore in eastern Long Island Sound, and during May 2010 bottom photographs and surficial sediment data were acquired as part of a ground-truth reconnaissance survey of this area. Two interpretive data layers were derived from the multibeam echo-sounder and the ground-truth data used to verify them. For more information on the ground-truth survey see http://quashnet.er.usgs.gov/data/2010/10015/