OFR54 Bedrock Geologic Map of the Delaware Piedmont
The Piedmont rock units in Delaware, and bedrock geologic map of Schenck et al. (2000) are revised in this report based on new rock geochemistry, geochronometric data, petrography, and recent detailed mapping. Major revisions include:
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.
Wetlands park brings hope to Wilmington community plagued by flooding
Fine- to medium-grained, equigranular biotite tonalite usually occurring as rounded boulders. Tonalites are leucocratic (15 to 25% modal mafic minerals), light gray to buff on fresh surfaces, and locally contain mafic enclaves with reddish rims, the result of iron hydroxide staining. Possibly intrusive into the Perkins Run Gabbronorite Suite.
Streamgage: Shellpot Creek at Wilmington
USGS 01477800 SHELLPOT CREEK AT WILMINGTON, DE
Meteorological Station: New Castle County Airport
New Castle Airport Meterological Station
Meteorological Station: Porter Reservoir
Porter Reservoir Meteorological Station
Streamgage: Brandywine Creek at Wilmington
USGS 01481500 BRANDYWINE CREEK AT WILMINGTON, DE
Earthquake Felt Report
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