Bedrock Geologic Map of the Delaware Piedmont
Date
2021-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Newark, DE: Delaware Geological Survey, University of Delaware
Abstract
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:
• revising the extent of the Christianstead Gneiss and Windy Hills Gneiss
• abandoning the Wissahickon Formation as originally mapped in Delaware by Bascom (1902, 1905) and Bascom et al. (1909, 1920, and 1932) and replacing it with the Mt. Cuba Gneiss, a lithodeme of the West Grove Metamorphic Suite (Bosbyshell et al., 2012, 2013, 2014, 2015), and reserving the Wissahickon Schist/Formation for the metasediments on the east side of the Wilmington Complex magmatic arc and referring to them herein as Wissahickon Formation (restricted sense)
• extending the Rosemont Shear Zone from Pennsylvania southwest through Delaware to Maryland separating the Mt. Cuba Gneiss and the Wilmington Complex
• formally naming and describing two new units in the Wilmington Complex - the Greenville Gabbro and the Thompsons Bridge Gneiss.
Additional Notes
Plate 1 of OFR54 can also be viewed in a Web Mapping Application. Layers can be turned on and off and manipulated under the "Layers" icon in the upper right hand corner. Cross section is available by clicking on the cross section line. Rock unit descriptions available by clicking on the geologic map.
OFR54 Plate 1 (Bedrock Geologic Map of the Delaware Piedmont) Web Mapping Application
Plate 1 Summary
The vector data set contains the rock unit polygons for the surficial geology for DGS Open File Report 54 - Plate 1. The Piedmont rock units in Delaware, and bedrock geologic map of Schenck et al. (2000) are revised on this map based on new rock geochemistry, geochronometric data, petrography, and recent detailed mapping. Major revisions include:
• revising the extent of the Christianstead Gneiss and Windy Hills Gneiss
• abandoning the Wissahickon Formation as originally mapped in Delaware by Bascom (1902, 1905) and Bascom et al. (1909, 1920, and 1932) and replacing it with the Mt. Cuba Gneiss, a lithodeme of the West Grove Metamorphic Suite (Bosbyshell et al., 2012, 2013, 2014, 2015), and reserving the Wissahickon Schist/Formation for the metasediments on the east side of the Wilmington Complex magmatic arc and referring to them herein as Wissahickon Formation (restricted sense)
• extending the Rosemont Shear Zone from Pennsylvania southwest through Delaware to Maryland separating the Mt. Cuba Gneiss and the Wilmington Complex
• formally naming and describing two new units in the Wilmington Complex - the Greenville Gabbro and the Thompsons Bridge Gneiss.
Description
https://www.dgs.udel.edu/publications/ofr54-bedrock-geologic-map-delaware-piedmont
Keywords
Paleozoic Era, Silurian Period, Ordovician Period, Cambrian Period, Precambrian, Wilmington Complex, Iron Hill Gabbro, Bringhurst Gabbro, Greenville Gabbro, Arden Plutonic Super Suite, Ardentown Granitic Suite, Perkins Run Gabbronorite Suite, Thompson's Bridge Gneiss, Metapyroxenite and metagabbro (undifferentiated), Serpentinite, Brandywine Blue Gneiss, Rockford Park Gneiss, Mill Creek Metagabbro, Barley Mill Gneiss, Montchanin Metagabbro, Christianstead Gneiss, Faulkland Gneiss, Windy Hills Gneiss, diabase, Pegmatite, West Grove Metamorphic Suite, Doe Run Schist, Laurels Schist, Mt Cuba Gneiss, White Clay Creek Amphibolite, Kennett Square Amphibolite, Glenarm Group, Cockeysville Marble, Setters Formation, Baltimore Gneiss, metamorphic, igneous, bedrock, Sillimanite, Biotite, Muscovite, Garnet, Magnetite, Quartz, Plagioclase, Microcline, Olivine, Pyroxene, Orthopyroxene, Orthoclase, Clinopyroxene, Clinozoisite, Amphibole, Hornblende, Anthophyllite, Serpentine, cummingtonite, Actinolite, Map Application, New Castle County Delaware, Newark, Stanton, Hockessin, Wilmington, Claymont, Greenville, Appalachian Piedmont, Ardentown, Ardencroft, New Castle, Newport