Geologic Map of the Newark West, Newark East, and Wilmington South Quadrangles, Delaware

Abstract

Geologic mapping was conducted at 1:12,000 with a 1-ft topographic contour basemap. In some instances, stratigraphic boundaries drawn at topographic breaks and highs reflect detailed mapping using LiDAR data. Elevations of stratigraphic contacts along stream valleys are projected from subsurface data. Except for a few erosional bluffs, these contacts are covered by colluvium. This map supersedes this portion of Geologic Map of New Castle County, Delaware: Delaware Geological Survey Geologic Map Series No. 13 (Ramsey, 2005a), Geology of the Newark area, Delaware: Delaware Geological Survey Geologic Map Series No. 3 (Woodruff and Thompson, 1972), and Geology of the Wilmington area, Delaware: Delaware Geological Survey Geologic Map Series No. 4 (Woodruff and Thompson, 1975). Piedmont bedrock units are not included on this map and a generalized cutoff is drawn beyond which Coastal Plain units have not been recognized. Where shown on the map, the Piedmont is saprolite, the weathered zone that overlies the unweathered bedrock. Schenck (2021) and Schenck and others (2000) document the Piedmont stratigraphic units in detail.