Return to search

INTEGRATED SEISMIC-REFLECTION AND MICROGRAVITY IMAGING ACROSS THE SOUTHERN BOUNDARY OF THE CHARLESTON UPLIFT, NEW MADRID SEISMIC ZONE, USA

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.

Identiferoai:union.ndltd.org:uky.edu/oai:uknowledge.uky.edu:ees_etds-1080
Date01 January 2019
CreatorsBurford, Drew D., Jr.
PublisherUKnowledge
Source SetsUniversity of Kentucky
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceTheses and Dissertations--Earth and Environmental Sciences

Page generated in 0.0018 seconds