Date of Award

Winter 2020

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

School

Biological, Environmental, and Earth Sciences

Committee Chair

Dr. Jeremy Deans

Committee Chair School

Biological, Environmental, and Earth Sciences

Committee Member 2

Dr. Mark Puckett

Committee Member 2 School

Biological, Environmental, and Earth Sciences

Committee Member 3

Mr. Tony Stuart

Committee Member 3 School

Biological, Environmental, and Earth Sciences

Abstract

The Mesozoic Louann Salt extends through the northern GOM, extending onshore from eastern Texas to western Alabama and Florida. Along the landward terminus of the salt is a system of peripheral faults, including the Gilbertown Fault Zone bordering the Mississippi Interior Salt Basin to the north and east. This study sought to constrain the timing of fault movement and determine its relationship to the baswinward evacuation of Louann Salt through the use of a 3D seismic survey and well logs. By mapping Mesozoic formations and the peripheral fault system, lateral changes in formation thickness were used to generate fault expansion indices (FEI) and formation thickness charts, whereas well logs were utilized for finding formation tops and density. Through comparing the timing of fault slip, salt evacuation, lateral differential loading, and density changes, this study suggests the evacuation of salt flow initiated before an average stratigraphic density inversion formed and before more faults slipped. This indicates that faults moved as a passive response to salt evacuation. Multiple peaks in fault slip along all of the faults are observed through the Mesozoic with some differences in timing and magnitude, but patterns of slip across all faults indicate main slip events during the deposition of the Cotton Valley Group, the Mooringsport Formation, and the Eutaw Formation. The record of fault motion makes clear that salt evacuation is episodic and increased during periods of greater deposition and density inversion.

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