Investigating processes of glacial erosion and cirque formation by numerical modeling and field observations in the Southern Sierra Nevada, California Public Deposited

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  • March 20, 2019
  • Belknap, Sabrina Marie
    • Affiliation: College of Arts and Sciences, Department of Geological Sciences
  • Existing rules for erosion by glaciers are inconsistent with observations of significant cirque retreat. To better understand the processes of cirque formation and expansion, two separate studies were commenced: a field study and a numerical model. These studies were designed to test the hypothesis that cirques ultimately form from fluctuating levels of glacial occupation. Morphometric characteristics of four cirques indicate that cirque expansion may result from growth of a riegel from bedrock shoulders. Variable ice flow directions determined from striae data in three of the cirques correlate with areas of greater ice thickness. Numerical modeling efforts show that overdeepenings may form from ice flow through existing constrictions, but only when a threshold quarrying rule is used. They also highlight the importance of the relative efficacy of abrasion and quarrying when modeling and indicate that quarrying is a more efficient process than abrasion.
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  • Oskin, Michael
  • Open access

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