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Site content related to keyword: "subsurface"

Delaware Offshore Geologic Inventory

Delaware Offshore Geologic Inventory Map
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Since 1992, the Delaware Geological Survey (DGS) has compiled a geologic database known as the Delaware Offshore Geologic Inventory (DOGI) that consists of sediment samples, radiocarbon and amino acid racemization dates, seismic profiles, and vibracores taken from the nearshore and inner continental shelf in state and federal waters. Most of the 366 vibracores are stored at the DGS on-site core and sample repository.

Minerals in Delaware

Minerals in Delaware

The description and identification of minerals in Delaware dates from the first quarter of the nineteenth century. During this time, both geologists and amateur mineral collectors have published on the minerals of Delaware including George Carpenter, Issac Lea, James Booth, and Henry duPont.

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Simulation of Groundwater Flow in Southern New Castle County, Delaware

Diagram of Conceptual Groundwater Flow Model
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To understand the effects of projected increased demands on ground water to supply water, a finite-difference, steady-state, nine-layer, groundwater flow model was used to simulate groundwater flow in the Coastal Plain sediments of southern New Castle County, Delaware. Results are published in DGS RI77

RI16 Application of Geophysics to Highway Design in the Piedmont of Delaware

RI16 Application of Geophysics to Highway Design in the Piedmont of Delaware

The feasibility of using geophysical techniques in determining the amount of overburden and the nature of the subsurface along a proposed highway was tested in the Piedmont area of Delaware. The area is underlain by crystalline rocks capped by varying amounts of unconsolidated material or regolith. Seismic refraction and surface resistivity methods were used at selected stations and the interpretations were later compared to results from test holes and to the material exposed in road cuts. In general, interpretation of the seismic refraction results compared quite well with test borings and with field observations made after construction was started. Resistivity data were inconclusive in themselves but provided some additional control points when correlated with seismic refraction data. With proper control, it is concluded that such techniques could be useful in the Piedmont of Delaware for highway planning.

HM11 Ground-Water Recharge Potential Kent County, Delaware

Ground-Water Recharge Potential Kent County, Delaware

The ground-water recharge potential map of Kent County, Delaware, is a compilation of 1:24,000-scale maps of the water-transmitting properties of sediments in the interval between land surface and 20 ft below land surface. Water-transmitting properties are a key factor in determining the amount of water that recharges Delaware’s aquifers and the susceptibility of aquifers used as sources of water supply to contamination from near-surface pollutant sources. The mapping methodology was developed by Andres (1991) for the geologic characteristics of the Atlantic Coastal Plain portion of Delaware. Mapping and methods development started in 1990 and the final maps were completed in 2002 (Andres et al., 2002). Additional information about the map and methodology and a list of cited references are presented on the reverse side. The mapping program was funded by the Delaware Department of Natural Resources and Environmental Control and the Delaware Geological Survey.