Reactivated basement structures in the central Savannah River area and their relationship to coastal plain deformation

Conference · Mon Mar 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:6117357

Cumbest, R J; Price, V ^[1]; Temples, T J ^[2]; Fallaw, W C ^[3]; Snipes, D S ^[4]

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1. Westinghouse Savannah River Co., Aiken, SC (United States)
2. Dept. of Energy, Aiken, SC (United States)
3. Furman Univ., Greenville, SC (United States). Dept. of Geology
4. Clemson Univ., SC (United States). Dept. of Earth Sciences

Structural surface mapping and geophysical studies have identified several faults in the crystalline basement and overlying Coastal Plain sedimentary sequences in the central Savannah River area. Major subsurface basement shear zones occur parallel to and near Upper Three Runs Creek and Tinker Creek and are associated with linear aeromagnetic anomalies. Reflection seismic imaging of the basement shows a band of southeast dipping events parallel to Upper Three Runs Creek. Drill core from basement contain phyllonites, mylonites, fault breccia and pseudotachylite. The magnetic anomalies also mark the boundary separating greenschist facies metavolcanic rocks from amphibolite facies felsic gneiss, schist, and amphibolite. These features are similar to those that characterize other Paleozoic faults of the Eastern Piedmont Fault system. Reflection seismic imaging shows the sub-Cretaceous unconformity as well defined and easily identified event as well as easily traced laterally extensive events in Coastal Plain sequences. The unconformity and sedimentary sequences are faulted or deformed in several locations which also coincide with changes in dip of the unconformity. In the vicinity of Upper Three Runs Creek the unconformity shows a broad warping across which the elevation drops to the southeast and sedimentary sequences show a marked rate of thickening southeast. This indicates deformation of the basement exerted a control on deposition of the Coastal Plain sediments with down to the southeast movement. The basement shear zones are closely associated with the Dunbarton basin and are probable reactivated Paleozoic structures associated with extensional basin development as commonly seen associated with extensional basins on the east coast of North America.

• OSTI ID: 6117357
• Report Number(s): CONF-9304188--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:4
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540250 -- Environment
Terrestrial-- Site Resource & Use Studies-- (1990-)
58 GEOSCIENCES
580000* -- Geosciences
BASEMENT ROCK
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
GEOMORPHOLOGY
GEOPHYSICAL SURVEYS
NATIONAL ORGANIZATIONS
SAVANNAH RIVER PLANT
SEDIMENTARY BASINS
SEISMIC SURVEYS
SITE CHARACTERIZATION
SURVEYS
US AEC
US DOE
US ERDA
US ORGANIZATIONS