Remote sensing of river kinematics and their expression in the modern and ancient stratigraphic record

Although the geomorphic and stratigraphic expression of rivers are inherently linked, major disconnects remain between the mechanisms and processes governing river kinematics in the modern and expression of these processes in the stratigraphic record. This dissertation approaches this enigma from both perspectives via analysis of modern river kinematics using timelapse satellite imagery and characterization of uniquely exposed ancient river deposits using photogrammetric and numerical modeling approaches. The research described herein focuses on three central themes: (1) the geomorphic and stratigraphic impact of perturbations (bend cutoffs and channel avulsions) on the large-scale kinematics of rivers; (2) the role of flood event-scale discharge variability on fine-scale patterns of erosion, deposition, and preservation along channel banklines; and (3) the three-dimensional nature of fluvial stratigraphy. Chapter 2 focuses on the map-view impact of bend cutoffs on subsequent lateral migration rates and patterns as captured by 37 years of Landsat satellite imagery using a newly developed automated channel extraction and tracking workflow called meandergraph. Results highlight direct linkages between formative post-cutoff bend curvature and subsequent map-view bend change at the cutoff site and in adjacent bends. Modeling results highlight challenges in predicting post-cutoff bend behavior with simple kinematic models but confirm post-cutoff bend curvature as an important contributor to planform bend change. Chapter 3 examines the role of event-scale discharge variability on patterns and magnitude of erosion and deposition along the Trinity River using a 7-year record of autonomously derived banklines from PlanetScope 3-m resolution optical imagery. This study is among the first to apply PlanetScope optical imagery to track spatiotemporal map-view river kinematics quantitatively. Results indicate linkages between peak and cumulative discharge on bankline kinematics, while illustrating the potential importance point bar erosion during low discharge conditions. Floods are shown to have a significant impact on net stratigraphic preservation and represent a significant fraction of deposits preserved within the channel over the 7-year period. Chapter 4 shifts focus to characterization of ancient fluvial processes, specifically processes and products of avulsion in the ancient stratigraphic record of the Cretaceous Cedar Mountain Formation in Utah, USA. This research integrates quantitative outcrop characterization with novel 3-D stratigraphic modeling approaches to reconcile linkages between avulsion processes and their 3-D expression in the stratigraphic record. Cumulatively, this research enables more informed interpretations and predictions of the nature of sedimentary deposits hypothesized to represent river avulsions observed on Earth and other planetary surfaces.

Name thesis:degree_name

Doctor of Philosophy

Discipline thesis:degree_discipline

Geological Sciences

Grantor

The University of Texas at Austin

Year dc:date.issued

2024

Author dc:creator

• Speed, Cole Michael

Advisors dc:contributor.advisor

• Sylvester, Z. (Zoltán)
• Mohrig, David

Committee members dc:contributor.committeemember

• Covault, Jacob A.
• Durkin, Paul R.
• Goudge, Timothy A.

• Remote sensing
• Optical satellite imagery
• Rivers
• Meandering
• Lidar
• Stratigraphy
• Geomorphology

Language dc:language.iso

English

Identifier URI

https://doi.org/10.26153/tsw/62865

OAI identifier oai:identifier

oai:repositories.lib.utexas.edu:2152/135545