University of Illinois Urbana-Champaign

Influence of spatially variable precipitation on passive margin escarpment evolution

Colberg, Jessica S.

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https://hdl.handle.net/2142/24265

Description

Title
Influence of spatially variable precipitation on passive margin escarpment evolution
Author(s)
Colberg, Jessica S.
Issue Date
2011-05-25T14:50:17Z
Director of Research (if dissertation) or Advisor (if thesis)
Anders, Alison M.
Department of Study
Geology
Discipline
Geology
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Keyword(s)
  • passive margin
  • passive margin escarpment
  • Western Ghats Great Escarpment
  • geomorphology
  • CASCADE
  • coupled topography and climate
  • landscape evolution
  • numerical model
Abstract
Passive margin escarpments are large-scale geomorphic features which persist over timescales of tens of millions of years. The maintenance of steep topography over these timescales challenges conventional understanding of fluvial erosion. Typical explanations for passive margin escarpments rely on lithospheric flexure and fluvial network geometry. I suggest a role for interactions between climate and landscape evolution motivated by the Western Ghats of India. The Western Ghats experience a wet, tropical climate with topographically-controlled spatially varying precipitation. Precipitation reaches a maximum in the escarpment foothills and decreases sharply with elevation. Using a numerical landscape evolution model, I simulate the effects of coupled climate and topography on an idealized escarpment, including the effects of lithospheric flexure, pre-existing fluvial network geometry, and variability in bedrock resistance. Spatially varying precipitation enhances the slope and lifespan of an escarpment in a similar manner to a resistant bedrock ridge parallel to the escarpment crest. Precipitation variability is a viable mechanism for maintaining a steep escarpment, indicating that the lifetime of such geomorphic features may be a strong function of climate and precipitation mechanisms.
Graduation Semester
2011-05
Permalink
http://hdl.handle.net/2142/24265
Copyright and License Information
Copyright 2011 Jessica S. Colberg

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