Date of Award

2018

Document Type

Open Access Thesis

Department

Earth and Ocean Sciences

Sub-Department

College of Arts and Sciences

First Advisor

James H. Knapp

Abstract

The Helena Banks Fault Zone (HBFZ), first identified in the early 1980’s offshore Charleston, S.C., was originally interpreted to be a major, high-angle, basin-bounding normal fault associated with Mesozoic rifting. Subsequent work suggests that (1) Mesozoic rift basins are not present on the continental shelf of South Carolina, (2) the HBFZ originated as a strike-slip fault within Paleozoic sedimentary rocks of the Suwannee Basin sequence, (3) a mafic intrusion inferred from aeromagnetic data is coincident with a broadly circular zone of highly-complex faulting along the north-eastward continuation of the HBFZ where (4) up to 300 m of local relief can be documented on the post-rift unconformity. These relations may indicate that the HBFZ served as a locus for magmatic intrusion in the upper crust, effectively stitching the fault where it appears to be inactive since Cretaceous time, in contrast to areas along strike to the southwest which may be currently seismically active. Analysis of 2D multichannel seismic reflection data, collected offshore from Charleston, is crucial to identify the continuation of the Helena Banks Fault Zone (HBFZ) in order to fully document both the lateral and vertical extent of the HBFZ, as well as re-evaluate the evidence for origin and evolution of the fault zone. According to Behrendt & Yuan (1987), the northeast-striking Helena Bank fault is approximately 110 km long strike-slip fault and trends between N68E and N77E, with a mostly N72E. Previous studies indicate that the HBFZ located 10m below the sea floor and also the most recent movement is during post-Miocene or Pliocene time (Behrendt et al., 1981). The purpose of this research to find continuation of the Helena Banks Fault in the North-East direction and to analysis its’ structure basing on interpretation of 102 seismic lines.

Included in

Geology Commons

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