Electronic Theses and Dissertations

Identifier

2487

Date

2015

Date of Award

10-23-2015

Document Type

Thesis

Degree Name

Master of Science

Major

Earth Sciences

Concentration

Geology

Committee Chair

Roy B. Van Arsdale

Committee Member

Randy T. Cox

Committee Member

David Lumsden

Abstract

The Reelfoot reverse fault, a major northwest-striking and southwest-dipping fault within the New Madrid seismic zone, is projected to cross from the Mississippi River floodplain into the loess-covered Mississippi River bluffs immediately southeast of Reelfoot Lake in northwestern Tennessee. A pressing problem is whether the Reelfoot fault (and its associated Tiptonville dome) crosses the northeast-striking Axial fault zone as once continuous fault or is segmented into two discreet faults (the Reelfoot North and the Reelfoot South faults). This investigation uses geologic mapping, geomorphic analysis, and seismic reflection to locate and determine the history of the Reelfoot (South) fault within the Mississippi River bluffs. A geologic profile of the ~3.1 Ma Upland Complex (Mississippi River terrace) within the Mississippi River bluffs reveals an apparent ~6 m of up-to-the-south displacement at the location of the projection of the Reelfoot (South) fault. Six meter high creek terraces within the bluffs are primarily confined to the Tiptonville dome thus indicating ~6 m of late Wisconsin or Holocene uplift on the Reelfoot fault and Tiptonville dome. Gravel pit distribution and anomalous stream orientations also support the Reelfoot (South) fault passing into the bluffs. Seismic reflection profiles acquired for this investigation reveals the Reelfoot (South) fault displaces the tops of the Paleozoic section 65 m, Cretaceous 40 m, Paleocene Porters Creek Clay 31 m, Eocene Wilcox Group 20 m, and Eocene Memphis Sand 16 m within the bluffs. A previously uninterpreted reflection profile completed by the USGS in 2008 reveals an up-to-the-north reverse fault 4.3 km south of the Reelfoot fault that displaces the top of the Paleozoic section 20 m and top of the Memphis Sand 6 m. This fault, or backthrust, of the Reelfoot South fault appears to be the southwest margin of the Tiptonville dome. Comparison of previous seismic reflection lines completed both northwest and southeast of the seismic reflection lines acquired for this project, reveals similar displacement histories on common stratigraphic reflectors suggesting that the Reelfoot fault has been one continuous fault zone across the Axial fault zone. The Reelfoot fault is also not laterally offset across the Axial fault zone further supporting that the Reelfoot fault is one continuous fault.

Comments

Data is provided by the student.

Library Comment

dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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