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Quantitative evaluation of nivation in the Colorado Front Range

1976; Geological Society of America; Volume: 87; Issue: 8 Linguagem: Inglês

10.1130/0016-7606(1976)87 2.0.co;2

1943-2674

Colin E. Thorn,

Landslides and related hazards

Research Article| August 01, 1976 Quantitative evaluation of nivation in the Colorado Front Range COLIN E. THORN COLIN E. THORN 1Department of Geography, University of Maryland, College Park, Maryland 20742 Search for other works by this author on: GSW Google Scholar Author and Article Information COLIN E. THORN 1Department of Geography, University of Maryland, College Park, Maryland 20742 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1976) 87 (8): 1169–1178. https://doi.org/10.1130/0016-7606(1976)87 2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation COLIN E. THORN; Quantitative evaluation of nivation in the Colorado Front Range. GSA Bulletin 1976;; 87 (8): 1169–1178. doi: https://doi.org/10.1130/0016-7606(1976)87 2.0.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 A quantitative evaluation of nivation in a mid-latitude alpine environment has been derived from an intensive study of two snow patches on Niwot Ridge, in the Colorado Front Range. Four research hypotheses were tested: nivation intensifies (1) mechanical weathering, (2) mechanical transport, (3) chemical weathering, and (4) chemical transport.Nivation does not increase the number of freeze-thaw cycles (mechanical weathering); rather, snow patches redistribute the pattern of occurrence of freeze-thaw cycles by preventing wintertime cycles and increasing springtime cycle totals. Intensification of mechanical weathering can only result from increased cycle effectiveness. In contrast to a snowfree site, nivation increases the mechanical transport of sand, silt, and clay by an order of magnitude. Sheetwash and rill flow dominate mechanical transport. The snowpack itself is protective, sediment removal being focused downslope of the retreating snow margin. Chemical weathering is increased by a factor of two to four by a snow patch. Variations in weathering rinds indicate that chemical weathering is produced by concentration of meltwater and (or) snowpack free water.Within a nivation hollow, chemical and mechanical degradation are approximately equal. On Niwot Ridge, degradation increased from 0.0001 mm/yr on a snowfree site to 0.0074 mm/yr within a nivation hollow. Slope profile through a nivation hollow corresponds to slope forms derived theoretically from the continuity equation. Snow-patch enlargement leads to downslope lengthening of the nivation hollow, whereas regular, complete meltout promotes incision of the hollow headwall into the hillside. 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.