Periglacial weathering and headwall erosion in cirque glacier bergschrunds

Abstract

Research Article| September 01, 2012 Periglacial weathering and headwall erosion in cirque glacier bergschrunds Johnny W. Sanders; Johnny W. Sanders 1Department of Earth and Planetary Science, University of California–Berkeley, Berkeley, California 94720, USA Search for other works by this author on: GSW Google Scholar Kurt M. Cuffey; Kurt M. Cuffey 1Department of Earth and Planetary Science, University of California–Berkeley, Berkeley, California 94720, USA2Department of Geography, University of California–Berkeley, Berkeley, California 94720, USA Search for other works by this author on: GSW Google Scholar Jeffrey R. Moore; Jeffrey R. Moore 3Department of Earth Sciences, ETH Zürich, 8092 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar Kelly R. MacGregor; Kelly R. MacGregor 4Geology Department, Macalester College, St. Paul, Minnesota 55105, USA Search for other works by this author on: GSW Google Scholar Jeffrey L. Kavanaugh Jeffrey L. Kavanaugh 5Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Johnny W. Sanders 1Department of Earth and Planetary Science, University of California–Berkeley, Berkeley, California 94720, USA Kurt M. Cuffey 1Department of Earth and Planetary Science, University of California–Berkeley, Berkeley, California 94720, USA2Department of Geography, University of California–Berkeley, Berkeley, California 94720, USA Jeffrey R. Moore 3Department of Earth Sciences, ETH Zürich, 8092 Zürich, Switzerland Kelly R. MacGregor 4Geology Department, Macalester College, St. Paul, Minnesota 55105, USA Jeffrey L. Kavanaugh 5Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Publisher: Geological Society of America Received: 20 Feb 2012 Revision Received: 19 Mar 2012 Accepted: 22 Mar 2012 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2012 Geological Society of America Geology (2012) 40 (9): 779–782. https://doi.org/10.1130/G33330.1 Article history Received: 20 Feb 2012 Revision Received: 19 Mar 2012 Accepted: 22 Mar 2012 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Johnny W. Sanders, Kurt M. Cuffey, Jeffrey R. Moore, Kelly R. MacGregor, Jeffrey L. Kavanaugh; Periglacial weathering and headwall erosion in cirque glacier bergschrunds. Geology 2012;; 40 (9): 779–782. doi: https://doi.org/10.1130/G33330.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Glaciers produce cirques by scouring their beds and sapping their headwalls, but evidence to constrain models of these processes has been elusive. We report a suite of environmental measurements from three cirque glacier bergschrunds, including the first temperature series recorded at depth throughout most of an annual cycle. Compared to the ambient air, the bergschrunds were colder in summer and warmer in winter. Freeze-thaw cycles were rare, and relatively stable subfreezing temperatures persisted from November until May. Using a model for rock fracturing driven by ice segregation, we demonstrate that favorable conditions for fracturing occur not only on the headwall above the glacier, but also within the bergschrund, where periglacial weathering and glacial transport can act together to drive cirque headwall retreat. A small (∼3 °C) year-round decrease in temperatures to conditions more typical of the Pleistocene would likely intensify the weathering process. Though so far ignored in all glacial landscape evolution models, the bergschrund likely plays an essential role in the sculpting of alpine landscapes. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.