Year of Publication

2019

Degree Name

Master of Science (MS)

Document Type

Master's Thesis

College

Arts and Sciences

Department

Earth and Environmental Sciences (Geology)

First Advisor

Dr. Edward W. Woolery

Abstract

The Charleston Uplift (CU), a 30-km-long by 7-km-wide, N46°E-oriented subsurface geologic anomaly in the northern Mississippi embayment near Charleston, Missouri, exhibits up to 36 m of vertical relief across the Paleogene/Quaternary unconformity. Subsurface structural relief, along with the CU’s coincident boundary alignment with contemporary microseismicity and the New Madrid North Fault (NMNF), suggest a structural origin. Subsequent seismic soundings indicate vertical structural relief is present in Cretaceous and Paleozoic horizons, supporting the fault-controlled origin. The southern boundary (CU-s) had not been investigated, nor had any direct fault images been acquired. Integrated microgravity and seismic-reflection methods across the inferred CU-s establish the first image of this fault.

Forward modeling indicated that the vertical variation of strata across the CU-s would induce a microgravity anomaly of 1.6 mGal. The observed microgravity anomaly survey across the southern boundary is 1.616 ± .004 mGal, and is consistent with the tectonic interpretation. A subsequently acquired seismic-reflection profile corroborates this interpretation. The imaged fault shows approximately 60, 35, and 35 meters of vertical down-to-the-south throw across the tops of Paleozoic, Cretaceous, and Tertiary horizons, respectively. This confirms the CU is not an erosional feature, but a structurally controlled extension of the NMNF.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2019.336

Funding Information

This thesis was made possible through the support of the Kentucky Research Consortium for Energy and Environment, the Department of Energy and the Kentucky Geological Survey.

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