The sediment data presented in this data layer were from a geochemical study sited in Great Bay Estuary, New Hampshire. The analog data were originally converted into digital form for inclusion in a Gulf of Maine Contaminated Sediments Database.

The sediment data presented in this data layer were from an ecological study sited near the Portsmouth Naval Shipyard, Kittery, Maine. The analog data were originally converted into digital form for inclusion in a Gulf of Maine Contaminated Sediments Database.

Surficial geologic maps play and important role in understanding the present sea floor and the processes that shape it. Between 1984 and 1991, over 1,700 bottom sample stations were occupied in the northwestern Gulf of Maine. Although the data were originally collected for a variety of research projects, contracts, and graduate student theses, they were eventually compiled as part of a Maine Geological Survey and University of Maine program to map the inner continental shelf of this region.

Short cores were collected on the continental rise off Georges Bank. The character of the sediments and measured bottom currents show that the Western Boundary Undercurrent is a significant factor in sediment transport and deposition along the east coast continental rise. Size data for the sand and mud fractions were estimated by the compilers by subtracting the percent carbonate (composed largely of sand-sized planktonic foraminifera) from the coarse fraction. Silt and clay were not differentiated; the fine fraction is reported as mud.

The sediments and geomorphology of a portion of the northeastern continental shelf between Hudson Canyon and Georges Bank have been investigated. Wave-cut terraces at 13, 45, 65, and 80 fathoms indicate four former low sea levels, while concentrations of beach ridges around 35 fathoms reveal a fifth. The pre-Holocene drainage pattern, still exposed over part of the area, shows that Block Channel was the main stream system which drained most of southern New England. The surface sediments on the western part of the study area are Late Pleistocene fluvial deposits. Overlying these coarse deposits in the central part of the outer shelf is a sandy silt facies that is also relict. The youngest facies and the only area of present deposition, is in the northeastern part where sand eroded from Nantucket Shoals is being deposited on the shelf.

This data set contains sediment grain size and textural information from the Continental Margin Program. The program was a joint collaboration between the U.S. Geological Survey and the Woods Hole Oceanographic Institution during the 1960s to conduct a geological reconnaissance investigation of the continental shelf and slope off the Atlantic coast of the United States. Only those records with complete size analyses are included in this data set. Other stations where only lithologic descriptions are available have been excluded.

The data in this layer are from a number of published and unpublished sets produced by the Bigelow Laboratory. The source projects were conducted primarily to examine contaminant (e.g. trace metals, PAHs) distributions, but also produced sediment textural data. The data were originally converted into digital format for inclusion in the Gulf of Maine Contaminated Sediments Database.

The data in this layer are from a study that evaluated and documented the historic and projected future dredging and dredged material disposal needs of the coastal rivers and harbors of the states of Maine and New Hampshire. Documentation of historic dredging and disposal activities was accomplished through the collection of data primarily from the files of the ACOE, New England Division, in Waltham, Massachusetts, supplemented by information from the states of Maine and New Hampshire and previously published reports. This historic dredging occurred between 1950-1993 and involved 499 dredging events.

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA) and the Massachusetts Office of Coastal Zone Management (MA CZM), is producing detailed geologic maps of the coastal sea floor. Imagery, originally collected by NOAA for charting purposes, provide a fundamental framework for research and management activities along this part of the Massachusetts coastline, show the composition and terrain of the seabed, and provide information on sediment transport and benthic habitat. Interpretive data layers were derived from multibeam echo-sounder and sidescan sonar data collected in Great Round Shoal Channel, a passage through the shoals at the eastern entrance to Nantucket Sound, off Cape Cod, Massachusetts. In June 2006, bottom photographs and surficial sediment data were acquired as part of a ground-truth reconaissance survey.

Gravel, sand, silt, and clay contents were determined for samples from Narragansett Bay and the adjacent Rhode Island Shelf. In the Narragansett Bay system, clayey silt and sand-silt-clay are the most abundant sediments. Sand is abundant locally and on the inner shelf. In general, toward the lower passages of the Bay the sediments show a progressive change to coarser textures.