Glacial erosion: status and outlook
Glacier-erosion rates range across orders of magnitude, and much of this variation cannot be attributed to basal sliding rates. Subglacial till acts as lubricating ‘fault gouge’ or ‘sawdust’, and must be removed for rapid subglacial bedrock erosion. Such erosion occurs especially where and when moul...
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2019-12-01
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| Series: | Annals of Glaciology |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S0260305519000387/type/journal_article |
| _version_ | 1827995993714458624 |
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| author | R. B. Alley K. M. Cuffey L. K. Zoet |
| author_facet | R. B. Alley K. M. Cuffey L. K. Zoet |
| author_sort | R. B. Alley |
| collection | DOAJ |
| description | Glacier-erosion rates range across orders of magnitude, and much of this variation cannot be attributed to basal sliding rates. Subglacial till acts as lubricating ‘fault gouge’ or ‘sawdust’, and must be removed for rapid subglacial bedrock erosion. Such erosion occurs especially where and when moulin-fed streams access the bed and are unconstrained by supercooling or other processes. Streams also may directly erode bedrock, likely with strong time-evolution. Erosion is primarily by quarrying, aided by strong fluctuations in the water system driven by variable surface melt and by subglacial earthquakes. Debris-bed friction significantly affects abrasion, quarrying and general glacier flow. Frost heave drives cirque headwall erosion as winter cold air enters bergschrunds, creating temperature gradients to drive water flow along premelted films to growing ice lenses that fracture rock, and the glacier removes the resulting blocks. Recent subglacial bedrock erosion and sediment flux are in many cases much higher than long-term averages. Over glacial cycles, evolution of glacial-valley form feeds back strongly on erosion and deposition. Most of this is poorly quantified, with parts open to argument. Glacial erosion and interactions are important to tectonic and volcanic processes as well as climate and biogeochemical fluxes, motivating vigorous research. |
| first_indexed | 2024-04-10T05:05:09Z |
| format | Article |
| id | doaj.art-b800bb2037484d5fba43f2b0eaf6f80b |
| institution | Directory Open Access Journal |
| issn | 0260-3055 1727-5644 |
| language | English |
| last_indexed | 2024-04-10T05:05:09Z |
| publishDate | 2019-12-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Annals of Glaciology |
| spelling | doaj.art-b800bb2037484d5fba43f2b0eaf6f80b2023-03-09T12:27:37ZengCambridge University PressAnnals of Glaciology0260-30551727-56442019-12-016011310.1017/aog.2019.38Glacial erosion: status and outlookR. B. Alley0https://orcid.org/0000-0003-1833-0115K. M. Cuffey1https://orcid.org/0000-0001-9314-2996L. K. Zoet2https://orcid.org/0000-0002-9635-4051Department of Geosciences and Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA16802, USADepartment of Geography, University of California–Berkeley, Berkeley, CA94720, USADepartment of Geoscience, University of Wisconsin–Madison, Madison, WI53706, USAGlacier-erosion rates range across orders of magnitude, and much of this variation cannot be attributed to basal sliding rates. Subglacial till acts as lubricating ‘fault gouge’ or ‘sawdust’, and must be removed for rapid subglacial bedrock erosion. Such erosion occurs especially where and when moulin-fed streams access the bed and are unconstrained by supercooling or other processes. Streams also may directly erode bedrock, likely with strong time-evolution. Erosion is primarily by quarrying, aided by strong fluctuations in the water system driven by variable surface melt and by subglacial earthquakes. Debris-bed friction significantly affects abrasion, quarrying and general glacier flow. Frost heave drives cirque headwall erosion as winter cold air enters bergschrunds, creating temperature gradients to drive water flow along premelted films to growing ice lenses that fracture rock, and the glacier removes the resulting blocks. Recent subglacial bedrock erosion and sediment flux are in many cases much higher than long-term averages. Over glacial cycles, evolution of glacial-valley form feeds back strongly on erosion and deposition. Most of this is poorly quantified, with parts open to argument. Glacial erosion and interactions are important to tectonic and volcanic processes as well as climate and biogeochemical fluxes, motivating vigorous research.https://www.cambridge.org/core/product/identifier/S0260305519000387/type/journal_articleGlacial geologyglacial geomorphologyglacial tills |
| spellingShingle | R. B. Alley K. M. Cuffey L. K. Zoet Glacial erosion: status and outlook Annals of Glaciology Glacial geology glacial geomorphology glacial tills |
| title | Glacial erosion: status and outlook |
| title_full | Glacial erosion: status and outlook |
| title_fullStr | Glacial erosion: status and outlook |
| title_full_unstemmed | Glacial erosion: status and outlook |
| title_short | Glacial erosion: status and outlook |
| title_sort | glacial erosion status and outlook |
| topic | Glacial geology glacial geomorphology glacial tills |
| url | https://www.cambridge.org/core/product/identifier/S0260305519000387/type/journal_article |
| work_keys_str_mv | AT rballey glacialerosionstatusandoutlook AT kmcuffey glacialerosionstatusandoutlook AT lkzoet glacialerosionstatusandoutlook |