Delaware

GM26 Geologic Map of the Cecilton and Middletown Quadrangles, Delaware

Mapping was conducted using field maps at a scale of 1:12,000 with 2-ft contours. Stratigraphic boundaries drawn at topographic breaks reflect detailed mapping using contours not shown on this map. Most stratigraphic units mapped in stream valleys are projected from subsurface data. Except for a few erosional bluffs, these units are covered by colluvium. This map supersedes Geology of the Middletown-Odessa Area, Delaware: Delaware Geological Survey Geologic Map Series No. 2 (Pickett and Spoljaric, 1971).

Access to real-time DGS groundwater level data

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Did you know that DGS offers real-time groundwater level data? This service, operated in collaboration with the Delaware Environmental Observing System (DEOS) and the Delaware Solid Waste Authority (DSWA) has been available for several years.

New digital water quality dataset released

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DGS has released a new dataset “The Determination of Total Nutrient Loads from the Nanticoke Watershed above the USGS Nanticoke River near Bridgeville Gauging Site (01487000) from Data Provided by an Automated Nutrient Analyzer “.

OFR55 Delaware Geological Survey Petrographic Data Viewer

Petrography is a branch of geoscience focused on the description and classification of rocks, primarily by microscopic study of optical properties of minerals. A thin sliver of rock is cut from a sample, mounted on a glass slide, ground to approximately 30 microns (0.03mm), and viewed under a microscope that uses polarized light. By observing the colors produced as plain polarized light and crossed (90 degrees) polarized light shines through the minerals, petrologists can determine the minerals that comprise the sampled rock.

GM25 Geologic Map of Offshore Delaware

Delineation of map units is based on sediment-core descriptions (e.g., texture, color, and composition) from 469 locations and seafloor morphology, which was assessed from a seamless NOAA/USGS topo-bathymetric model (Pendleton et al., 2014).