Controls on eolian landscape evolution in fractured bedrock

Geophysical Research Letters
By: , and 

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Abstract

Wind abrasion is important for planetary landscape evolution, and wind‐abraded bedrock landscapes contain many landforms that are difficult to interpret. Here we exploit a natural experiment in Chile where topographic shielding by an upwind lava flow yields diverse erosional landforms in a downwind ignimbrite. Using a 3‐D topographic wind model, we find that low velocities in the wake of a lava lobe coincide with a transition from landforms reflecting fracture‐parallel erosion to flow‐parallel erosion. Erosion rates across these landforms vary with shear velocity and abrasion susceptibility of the windward escarpment. We hypothesize that this morphologic threshold is controlled by whether particles can be lofted in suspension and overcome topographic steering imposed by fractured bedrock blocks. Within a phase space set by Rouse and Stokes numbers, our data illustrate that wind‐abraded landforms reflect a competition between the material skeleton of the landscape and the strength of the flow that shapes it.

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Publication type Article
Publication Subtype Journal Article
Title Controls on eolian landscape evolution in fractured bedrock
Series title Geophysical Research Letters
DOI 10.1029/2019GL083955
Volume 46
Issue 21
Year Published 2019
Language English
Publisher American Geophysical Union
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 9 p.
First page 12012
Last page 12020
Country Chile
Other Geospatial Antofogasta region, Central Andes Mountains
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