26 Geologic Maps, Geophysical Maps, 3-D Geologic Models, Digital Mapping Techniques, Map Derivatives, and Digital Map preparation (Posters)

This poster session will highlight new geologic maps, mapping programs, and innovations in geological mapping techniques, including data management, web accessibility, 3-dimensional maps and cross sections, and applications in engineering geology and water/land management.

Tuesday, 10 March 2026
9:00 AM - 5:00 PM
RCC, Lower Level Hall

New geologic map of the western half of the Emporia 30x60-minute quadrangle, Virginia and North Carolina

Paper number: 26-2
Program: Technical Sessions
Time: 9:00 AM – 9:00 AM

Authors

Abstract

We present a geologic map of the western half of the Emporia 30’x60’ quadrangle, VA and NC.  FEDMAP and EDMAP components of the USGS National Cooperative Geologic Mapping Program funded the mapping. These efforts were further supported by Earth MRI airborne magnetic and radiometric survey data, whole rock geochemical analyses, and LA-ICP-MS and SHRIMP U-Pb zircon geochronology.  The map was constructed for interstate bedrock and surficial correlation across the VA-NC state line, and to develop source-to-sink models for commercial heavy mineral deposits in uppermost Atlantic Coastal Plain (ACP) units. 

Bedrock is divided into amphibolite-facies infrastructural (IS) and greenschist-facies suprastructural (SS) peri-Gondwanan terranes of the eastern Piedmont province.  From west to east, these are the eastern Raleigh/Warren (IS), Spring Hope (SS), Triplet (IS), Roanoke Rapids (SS), and Dinwiddie (IS) terranes.  The Macon, Hollister, Gaston Dam, and Nottoway River dextral fault zones, of the eastern Piedmont fault system, separate these terranes.  The eastern Raleigh/Warren and Triplet terranes preserve Devonian paragneiss of mixed peri-Laurentian and peri-Gondwanan affinity.  Cambrian to Ediacaran metavolcanic and metasedimentary rocks comprise the Spring Hope terrane.  The Triplet terrane is a fault-bounded sliver of the eastern Raleigh/Warren terrane.  The Roanoke Rapids terrane consists of Cryogenian metavolcanic and metasedimentary rocks, Ediacaran bimodal intrusive rocks, and peri-Laurentian cover metasediments of Devonian and possibly younger age.  Cambrian schist and middle Paleozoic granitoid comprise the Dinwiddie terrane.  Late Paleozoic plutons, including the Alberta, Lawrenceville, Edgerton, and Dewitt-Sutherland, intrude the terranes and partially stitch the fault zones. 

ACP units range from Neogene Chesapeake Group to Pleistocene Charles City Formation.  Pliocene sand and gravel host heavy mineral resources rich in titanium minerals, zircon, and monazite, and are assigned to the upper part of the Chesapeake Group.  Reactivation of late Paleozoic to Mesozoic silicified cataclasite zones in Piedmont basement as Cenozoic faults influenced heavy mineral concentrations.  Fluvial terraces extend westward along major drainages and atop drainage divides and correlate with ACP units.  

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411584

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