Electronic Theses and Dissertations

Date

2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Earth Sciences

Committee Chair

Randel Tom Cox

Committee Member

Mervin Jerome Bartholomew

Committee Member

Roy Van Arsdale

Committee Member

David Arellano

Committee Member

Youngsang Kwon

Abstract

The first part of this study investigates the relationship between the degree of basin asymmetry and the dip amount and hardness of resistant rock in drainage basins located in gently dipping strata of the Cumberland Plateau region, Eastern Tennessee, USA. I examined basins in which the preferred direction of river migration is oriented near parallel to slightly oblique to dip direction of the underlying bedrock. This study suggests that in basins without horizontal bedrock, when bedrock dip increases in drainage basins having resistant rocks that are gentle to moderately dipping, asymmetry of the drainage basins decreases. The Relative River Deviation Index (RRI) is a newly defined geomorphic index that quantitatively measures the ratio of vertical downcutting to lateral shifting of streams in drainage basins with bedrock floors. The RRI analysis reveals that vertical incision dominates over lateral shifting as bedrock dip increases. Findings of this study indicate that an increase in the hardness of resistant rock promotes lateral river migration rather than vertical incision in areas with a bedrock dip ranging from approximately 4 to 12 degrees in the cratonic setting of the Cumberland Plateau. We also studied the variation in degree of basin asymmetry in response to changes in the dip and hardness of steeply dipping bedrock in the fold and thrust belt of the Arkoma Basin and the Ouachita Mountains area in Arkansas. This study suggests that bedrock dip does not significantly influence lateral river migration in this region. There is a weak negative relationship between these two variables in basins having a mean asymmetry vector and bedrock dip direction aligned, indicating that a steeper bedrock may promote the development of symmetric basins. The relationship between the hardness of the bedrock and the degree of basin asymmetry indicates a weak negative association. The weak correlation between these variables from this region indicates that the primary factor influencing lateral river migration in this area is neither bedrock dip amount nor hardness of the underlying bedrock. There is a need for a comprehensive study on the erosional resistance of rocks in this location, including other critical features of the rock mass.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest.

Notes

Embargoed until 4/10/2026

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Available for download on Friday, April 10, 2026

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