{ "culture": "en-US", "name": "", "guid": "", "catalogPath": "", "snippet": "To release the bedrock geologic map of the Delaware Piedmont in a form usable in a GIS, we have released this vector data file of DGS Open File Report No. 54. The update of earlier work and mapping of new units is important not only to geologists, but also to hydrologists who wish to understand the distribution of water resources, to engineers who need bedrock information during construction of roads and buildings, to government officials and agencies who are planning for residential and commercial growth, and to citizens who are curious about the rock units under their homes. Formal names are assigned to all geologic units according to the guidelines of the North American Stratigraphic Code (NACSN, 2021).", "description": "

The vector data set contains the rock unit polygons for Open File Report No. 54. The Piedmont rock units from Delaware Geological Survey Geologic Map No. 10 were revised in 2021 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.<\/SPAN><\/P>

<\/P><\/DIV><\/DIV><\/DIV>", "summary": "To release the bedrock geologic map of the Delaware Piedmont in a form usable in a GIS, we have released this vector data file of DGS Open File Report No. 54. The update of earlier work and mapping of new units is important not only to geologists, but also to hydrologists who wish to understand the distribution of water resources, to engineers who need bedrock information during construction of roads and buildings, to government officials and agencies who are planning for residential and commercial growth, and to citizens who are curious about the rock units under their homes. Formal names are assigned to all geologic units according to the guidelines of the North American Stratigraphic Code (NACSN, 2021).", "title": "Delaware Geological Survey Piedmont Geology Layer, 2021, 1:36,000 scale", "tags": [ "Delaware", "New Castle County", "geology", "Piedmont" ], "type": "", "typeKeywords": [], "thumbnail": "", "url": "", "minScale": 625000, "maxScale": 50000, "spatialReference": "", "accessInformation": "Digital Geology Layer for DGS Open File Report No. 54 (Bedrock Geologic Map of the Delaware Piedmont)", "licenseInfo": "

The Delaware Geological Survey (DGS) is constantly gathering data from multiple sources, interpreting the data, and reflecting its interpretations on maps. DGS's interpretations of multiple data sources are reflected in these polygons for Open File Report No. 54. Reasonable efforts have been made by DGS to verify that this map and the digital data provided herein is an accurate interpretation of the source data used in its preparation; however, this map may contain omissions and errors in scale, resolution, rectification, positional accuracy, development methodology, interpretations of source data and other circumstances. This map is also date specific and as additional data become available and as verification of source data continues, this map may be reinterpreted and updated by DGS without notification. This map was prepared for use at a scale of 1:36,000 and should not be used at larger scales for denotation of rock unit boundaries. This map should not be used for navigational, engineering, legal, or any other site-specific use. Nothing contained herein shall be deemed an expressed or implied waiver of the sovereign immunity of the State of Delaware or its duly authorized representatives, agents, or employees.<\/SPAN><\/P><\/DIV><\/DIV><\/DIV>" }