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Site content related to keyword: "Atlantic Coastal Plain"

GM14 Geologic Map of Kent County, Delaware

GM14 Geologic Map of Kent County, Delaware

This map shows the surficial geology of Kent County, Delaware at a scale of 1:100,000. Maps at this scale are useful for viewing the general geologic framework on a county-wide basis, determining the geology of watersheds, and recognizing the relationship of geology to regional or county-wide environmental or land-use issues. This map, when combined with the subsurface geologic information, provides a basis for locating water supplies, mapping ground-water recharge areas, and protecting ground and surface water. Geologic maps are also used to identify geologic hazards, such as flood-prone areas, to identify sand and gravel resources, and to support state, county, and local land-use and planning decisions.

Map Scale: 
100,000

GM13 Geologic Map of New Castle County, Delaware

GM13 Geologic Map of New Castle County, Delaware

This map shows the surficial geology of New Castle County, Delaware at a scale of 1:100,000. Maps at this scale are useful for viewing the general geologic framework on a county-wide basis, determining the geology of watersheds, and recognizing the relationship of geology to regional or county-wide environmental or land-use issues. This map, when combined with the subsurface geologic information, provides a basis for locating water supplies, mapping ground-water recharge areas, and protecting ground and surface water. Geologic maps are also used to identify geologic hazards, such as sinkholes and flood-prone areas, to identify sand and gravel resources, and for supporting state, county, and local land-use and planning decisions.

Map Scale: 
100,000
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GM11 Geology of the Ellendale and Milton Quadrangles, Delaware

GM11 Geology of the Ellendale and Milton Quadrangles, Delaware

The surficial geology of the Ellendale and Milton quadrangles reflects the geologic history of the Delaware Bay estuary and successive high and low sea levels during the Quaternary. Ramsey (1992) interpreted the Beaverdam Formation as deposits of a fluvial-estuarine system during the Pliocene. Sediment supply was high, in part due to geomorphic adjustments in the Appalachians related to the first major Northern Hemisphere glaciations around 2.4 million years ago. The Beaverdam Formation forms the core of the central Delmarva Peninsula around which wrap the Quaternary deposits.

Map Scale: 
24,000

GM9 Geology of the Seaford Area, Delaware

GM9 Geology of the Seaford Area, Delaware

This map shows the distribution of geologic units found at or near land surface. These units support agriculture and development, are mined for sand and gravel resources, and are the surface-to-subsurface pathway for water. Previous maps and reports covering the same of adjacent areas have focused on hydrogeology (Andres, 1994), surficial geology on a regional basis (Jordan, 1964, 1974; Owens and Denny, 1979, 1986; Denny et al., 1979; Ramsey and Schenck, 199), or subsurface geology (Hansen, 1981; Andres, 1986).

Map Scale: 
24,000

GM8 Geology of the Milford and Mispillion River Quadrangles, Delaware

Geology of the Milford and Mispillion River Quadrangles, Delaware

This map is the first detailed surficial geologic map in southern Kent and northern Sussex counties. Other maps covering the same or adjacent areas have focused on subsurface geology (Benson and Pickett, 1986), hydrogeology (Talley, 1982), or surficial geology on a regional basis (Jordan, 1964; Owens and Denny, 1979; Ramsey and Schenck, 1990). The purpose of this map is to show the distribution of geologic units found at or near the present land surface. These units are composed of the geologic materials that support agriculture and development, are mined for sand and gravel resources, and are the surface-to-subsurface pathway for water.

Map Scale: 
24,000

DGS Geologic Map No. 8 (Milford-Mispillion River Quadrangles) Dataset

DGS Geologic Map No. 8 (Milford-Mispillion River Quadrangles) Dataset

The scanned raster and vector datasets contains the rock unit polygons for the surficial geology for DGS Geologic Map No. 8 (Milford-Mispillion River Quadrangles). This map is the first detailed surficial geologic map in southern Kent and northern Sussex counties.

DGS Geologic Map No. 9 (Seaford area) Dataset

DGS Geologic Map No. 9 (Seaford area) Dataset

These raster and vector datasets contains the rock unit polygons for DGS Geologic Map No. 9 (Seaford). This map shows the distribution of geologic units found at or near land surface.

RI11 An Evaluation of the Resistivity and Seismic Refraction Techniques in the Search for Pleistocene Channels in Delaware

RI11 An Evaluation of the Resistivity and Seismic Refraction Techniques in the Search for Pleistocene Channels in Delaware

Pleistocene channels along the margins of the Atlantic Coastal Plain are developed in crystalline and Triassic sediments (Bonini and Hickok, 1958), or into the Cretaceous and Tertiary coastal plain sediments (Widmer, 1965). Deposits in these channels consist of sand and gravel with amounts of silt and clay. For example, the Bear area channel is 50 to 70 feet deep and contains up to 30 feet of sand and gravel overlain by sandy clay. Because they are usually more permeable than the older deposits into which the channels are developed, Pleistocene deposits are important in ground water studies for several reasons: (1) where they are thick enough they may be used as aquifers, as in the case of the Bear channel, and (2) these beds can effectively increase the recharge into the underlying aquifers by absorbing precipitation and transmitting the water to them.

DGS Publications

The core of much DGS work culminates in the release of data and findings in official DGS publications, including Open File Reports, Reports of Investigations, Geologic Maps, Hydrologic Maps, and Bulletins.