Ice-Cored Rock Glacier, Galena Creek, Northern Absaroka Mountains, Wyoming

Research Article| October 01, 1972 Ice-Cored Rock Glacier, Galena Creek, Northern Absaroka Mountains, Wyoming NOEL POTTER, JR. NOEL POTTER, JR. Department of Geology, Dickinson College, Carlisle, Pennsylvania 17013 Search for other works by this author on: GSW Google Scholar Author and Article Information NOEL POTTER, JR. Department of Geology, Dickinson College, Carlisle, Pennsylvania 17013 Publisher: Geological Society of America Received: 18 Aug 1971 Revision Received: 04 Apr 1972 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1972, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1972) 83 (10): 3025–3058. https://doi.org/10.1130/0016-7606(1972)833025:IRGGCN2.0.CO;2 Article history Received: 18 Aug 1971 Revision Received: 04 Apr 1972 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Get Permissions Search Site Citation NOEL POTTER; Ice-Cored Rock Glacier, Galena Creek, Northern Absaroka Mountains, Wyoming. GSA Bulletin 1972;; 83 (10): 3025–3058. doi: https://doi.org/10.1130/0016-7606(1972)833025:IRGGCN2.0.CO;2 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 SocietyGSA Bulletin Search Advanced Search Abstract Galena Creek rock glacier (44°38'30″ N., 109°47'30″ W., elevation 2,680 to 3,110 m, length 1.6 km) originates in a north-facing cirque. Although this rock glacier morphologically resembles others described elsewhere, its upvalley two-thirds is composed of a continuous layer of debris 1 to 1.5 m thick over relatively clean glacier ice and has a maximum measured surface velocity of 80 cm/yr. The downvalley one-third is mantled by 2 to 3 m of debris (measured by seismic refraction) over ice of unknown debris content; it has a maximum measured velocity of 14 cm/yr. The transition zone between these two regions has several large (6-m-high, 90-m-wide) lobes that override one another at a maximum measured velocity of 6 cm/yr.Accumulation occurs primarily as wind-drifted snow in a narrow lens-shaped area against the cirque headwall. Most of the coarse debris is not incorporated in the ice, but is carried past the steep (13° to 33°) snow accumulation area beneath the cirque headwall by snow avalanche and rockfall to form the debris mantle. The debris mantle is sorted, with coarse fragments dominant at the surface and a zone of fines just above the debris-ice contact. The ice beneath the debris mantle contains a maximum of 10 to 12 percent debris by volume, except in probable longitudinal septa downglacier from large debris concentrations in the source area.Intersecting ridges and furrows on the up-valley portion of the rock glacier probably differ in age, according to lichen sizes and ridge sharpness, and are probably formed by compression below steep reaches of the glacier and by collapse into crevasses.Ice-cored rock glaciers uniquely have a very low ratio of accumulation area to ablation area (1:7 in this case). This is mainly the result of an ablation rate beneath the debris mantle that is estimated to be about two orders of magnitude less than that of clean ice. The slow rate of addition of ice makes the glacier thin and thus slow-moving.Because of the debris cover, rock glaciers are not nearly so sensitive to climate as are clean glaciers. The lag effect between retreat of clean glaciers and deactivation of rock glaciers may be several thousand years, and therefore mountain glacier moraines should be correlated with rock glaciers only with extreme care. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.