DGS Annual Report

DGS Annual Report of Programs and Activities.

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Site content related to keyword: "Triassic Period"

248 to 208 mya

What is a fossil?

Tusk of Mammut americanum (American mastodon) discovered from the bottom of Delaware Bay after being caught in a scallop dredge. Pleistocene age.

If you think you may have found a Delaware dinosaur or any unusual fossil, the scientists at the Delaware Geological Survey at the University of Delaware, Newark campus would like to see it. It could provide important information on the geologic history of the First State.

Coastal Plain Rock Units (Stratigraphic Chart)

The geology of Delaware includes parts of two geologic provinces: the Appalachian Piedmont Province and the Atlantic Coastal Plain Province. The Piedmont occurs in the hilly northernmost part of the state and is composed of crystalline metamorphic and igneous rocks. This chart summarizes the age and distribution of the geologic units that are recognized in the state by the Delaware Geological Survey.

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.

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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.