The reconnaissance maps upon which this data set is based show the areal distribution of the major bottom sediment types covering the sea floor off eastern New England between Cape Ann and Casco Bay. The maps were intended as a guide to the future mapping of gravel, sand, silt, and clay, and because these sediments reflect the hydraulic conditions, they are also helpful for deducing the important sediment transport mechanisms.

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.

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.

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 sediment data contained in this set were produced as part of the site description and monitoring phases of an aquaculture demonstration project. The site is located off the coast of New Hampshire in the Gulf of Maine.

These data, which comprise part of the Smithsonian Institution Master Sediment data file, were abstracted by the staff of the Smithsonian Institution from materials submitted for archival by various groups and individuals. Most of the data in this set were collected by the National Ocean Service (NOS, formerly the U.S. Coast and Geodetic Survey) for the purpose of charting the coastal waters and navigable waterways of the United States. Prior to 1985, the NOS data were released as part of the National Ocean Surveys Hydrographic Database. After 1985, sediment samples collected by NOS during surveys were transferred to the Smithsonian for archival and textural analysis. All of the data in this set were collected post 1985 and have been processed by the Smithsonian. These data were supplied by the National Geophysical Data Center (NGDC), but this data set contains fields that are only a subset of those fields available in the full Smithsonian data set. For example, the data have been clipped to eliminate those stations that were not from the Gulf of Maine, Georges Bank, or the shelf and slope off southeastern New England. Last update of this file was July, 2001.

The detailed nature of relict sediments resulting from and related to the Holocene transgression is revealed through this sedimentological study of a densely sampled corridor across the southern New England continental shelf. These shelf sediments can be divided into an inner and middle clean sand facies and an outer shelf muddy sand facies. Sediment data supports the view that the outer muddy sediment is relict; the sharp "mud line" at about 35 fathoms results not from modern deposition, but from the winnowing more extensive muddy sediment.

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 data in this set are part of the "Ocean Pulse" benthic studies that were conducted on the U.S. northeast shelf by the National Marine Fisheries Service. This data set represents only those data collected as part of this program during 1981-1982 and off New England. Those stations occupied in the New York Bight are not included. Although chemical analyses (organic carbon and total Kjeldahl nitrogen) were also conducted, only textural descriptions are included here.