HAWKINS, W. BROWN, JR., and RICHARD H. GROSHONG, JR., University of Alabama, Tuscaloosa, AL

ABSTRACT: The Structure of the Livingston Fault Zone, Sumter County, Alabama

The Livingston fault zone trends across the Upper Cretaceous rocks of the coastal plain in Sumter County. Three bands of faulting have been recognized in the zone: a normal fault band to the northeast, a central reverse fault band, and another normal fault band to the southwest. All faults in the zone trend between 280 and 300 degrees and are purely dip slip. Dip slip is demonstrated by downdip striations and grooves on the fault surface.

A structure contour map, on the top of the Eutaw Formation, shows that the fault zone approximately coincides with the south-dipping steep limb of a monocline. Seismic profiles indicate that the monocline formed by inversion of an underlying Early Cretaceous half-graben. Initial sedimentation in the half-graben occurred during the Early Cretaceous and the master fault cuts

the Paleozoic-Mesozoic unconformity. Inversion of the structure began during the earliest Late Cretaceous (Tuscaloosa Formation) and continued into the earliest Tertiary (Clayton Formation).

AAPG Search and Discovery Article #90989©1993 GCAGS and Gulf Coast SEPM 43rd Annual Meeting, Shreveport, Louisiana, October 20-22, 1993.