Date of Award

1991

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Ocean & Earth Sciences

Program/Concentration

Geology

Committee Director

Ali Nowroozi

Committee Member

Ramesh Venkatakrishnan

Committee Member

Stanley S. Johnson

Call Number for Print

Special Collections LD4331.G4J36

Abstract

The Farmville basin is one of many Triassic basins which are found along the eastern coast of North America, and is the largest of the central string of basins in Virginia. Meta-volcanic and metasedimentary rocks of the Chopawamsic Formation, as well as felsic intrusives are the primary lithologies surrounding the basin. A detailed gravity survey was conducted along six roads that trend approximately NW-SE, across the basin. Geologic, gravity, magnetic, and radiometric data were used to develop a kinematic model. Gravity anomalies were isolated using two-dimensional harmonic analysis methods to isolate the local, and regional anomalies. This analysis indicates that all the gravity anomalies are a result of structures that lie within the upper 8 kilometers of crust. Results of gravity modelling indicate that the basin is a fault controlled half-graben with an east dipping border fault, and that the basin is relatively shallow. Maximum depth of the basin, occurs along State Road 636, and is less than 1 kilometer. Modelling further suggests that the deepest portion of the basin is opposite the border fault, and is a result of the master (primary) fault laying underneath the basin rocks. In addition to the kinematic model, this study provides evidence of unique geologic features, such as a diabase/ granophyre dike that has a maximum width of 688 meters.

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DOI

10.25777/sc6s-m109

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