Facies of supraglacial sedimentation on Icelandic and Alpine temperate glaciers
Supraglacial debris transported by temperate valley glaciers is classified as supraglacial morainic till, distinct from lodgement till, and melt-out and flow till species on polar glaciers. In Iceland and the Alps, where annual discharges of supraglacial morainic till vary from 200–2000 m 3 (compare...
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crcansciencepubl:10.1139/e79-121 2024-05-12T08:04:03+00:00 Facies of supraglacial sedimentation on Icelandic and Alpine temperate glaciers Eyles, Nicholas 1979 http://dx.doi.org/10.1139/e79-121 http://www.nrcresearchpress.com/doi/pdf/10.1139/e79-121 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 16, issue 7, page 1341-1361 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 1979 crcansciencepubl https://doi.org/10.1139/e79-121 2024-04-18T06:54:51Z Supraglacial debris transported by temperate valley glaciers is classified as supraglacial morainic till, distinct from lodgement till, and melt-out and flow till species on polar glaciers. In Iceland and the Alps, where annual discharges of supraglacial morainic till vary from 200–2000 m 3 (compared with a maximum discharge of 26 000 m 3 of lodgement till), till is deposited as three facies.Fades 1 occurs where supraglacial morainic till slows the rate of ice melt such that till is slowly superimposed on the subglacial surface in the form of stagnation or disintegration topography. The rate of deposition shows an initial slowing phase in response to (1) soil formation and (2) melt-out of englacial debris, followed by accelerated deposition accompanying the formation of thaw lakes. Continued mass movement of till on lake margins (backwasting) is more effective in destroying the ice-core than either top or bottom melt and prohibits accumulation of a distinct melt-out sediment. This situation can be contrasted with the style of sedimentation at polar glaciers. Where the depositing glacier is inactive and uncontrolled an unlineated till surface, typical of stagnation or disintegration topography, develops. Significantly, in terms of Pleistocene reconstructions, tracts of stagnation topography are being constructed at the margins of certain active Icelandic glaciers by sequential stagnation of a marginal rim of ice as the active glacier retreats up-valley.Fades 2 occurs where the till cover is too thin or too coarse and ice melt is unretarded and supraglacial morainic till is deposited as a dispersed bouldery veneer by dumping during which gravity sorting occurs. Dump moraine ridges frequently show internal bedding being ice-contact screes at time of formation but are not ice-cored. An active glacier produces a controlled distribution of landforms resulting in a lineated till surface.Facies 3 refers to those stratigraphic sequences where irregular or lensate till horizons alternate repeatedly with ice-contact ... Article in Journal/Newspaper glacier ice core Iceland Canadian Science Publishing Canadian Journal of Earth Sciences 16 7 1341 1361 |
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Canadian Science Publishing |
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crcansciencepubl |
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English |
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General Earth and Planetary Sciences |
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General Earth and Planetary Sciences Eyles, Nicholas Facies of supraglacial sedimentation on Icelandic and Alpine temperate glaciers |
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General Earth and Planetary Sciences |
description |
Supraglacial debris transported by temperate valley glaciers is classified as supraglacial morainic till, distinct from lodgement till, and melt-out and flow till species on polar glaciers. In Iceland and the Alps, where annual discharges of supraglacial morainic till vary from 200–2000 m 3 (compared with a maximum discharge of 26 000 m 3 of lodgement till), till is deposited as three facies.Fades 1 occurs where supraglacial morainic till slows the rate of ice melt such that till is slowly superimposed on the subglacial surface in the form of stagnation or disintegration topography. The rate of deposition shows an initial slowing phase in response to (1) soil formation and (2) melt-out of englacial debris, followed by accelerated deposition accompanying the formation of thaw lakes. Continued mass movement of till on lake margins (backwasting) is more effective in destroying the ice-core than either top or bottom melt and prohibits accumulation of a distinct melt-out sediment. This situation can be contrasted with the style of sedimentation at polar glaciers. Where the depositing glacier is inactive and uncontrolled an unlineated till surface, typical of stagnation or disintegration topography, develops. Significantly, in terms of Pleistocene reconstructions, tracts of stagnation topography are being constructed at the margins of certain active Icelandic glaciers by sequential stagnation of a marginal rim of ice as the active glacier retreats up-valley.Fades 2 occurs where the till cover is too thin or too coarse and ice melt is unretarded and supraglacial morainic till is deposited as a dispersed bouldery veneer by dumping during which gravity sorting occurs. Dump moraine ridges frequently show internal bedding being ice-contact screes at time of formation but are not ice-cored. An active glacier produces a controlled distribution of landforms resulting in a lineated till surface.Facies 3 refers to those stratigraphic sequences where irregular or lensate till horizons alternate repeatedly with ice-contact ... |
format |
Article in Journal/Newspaper |
author |
Eyles, Nicholas |
author_facet |
Eyles, Nicholas |
author_sort |
Eyles, Nicholas |
title |
Facies of supraglacial sedimentation on Icelandic and Alpine temperate glaciers |
title_short |
Facies of supraglacial sedimentation on Icelandic and Alpine temperate glaciers |
title_full |
Facies of supraglacial sedimentation on Icelandic and Alpine temperate glaciers |
title_fullStr |
Facies of supraglacial sedimentation on Icelandic and Alpine temperate glaciers |
title_full_unstemmed |
Facies of supraglacial sedimentation on Icelandic and Alpine temperate glaciers |
title_sort |
facies of supraglacial sedimentation on icelandic and alpine temperate glaciers |
publisher |
Canadian Science Publishing |
publishDate |
1979 |
url |
http://dx.doi.org/10.1139/e79-121 http://www.nrcresearchpress.com/doi/pdf/10.1139/e79-121 |
genre |
glacier ice core Iceland |
genre_facet |
glacier ice core Iceland |
op_source |
Canadian Journal of Earth Sciences volume 16, issue 7, page 1341-1361 ISSN 0008-4077 1480-3313 |
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http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e79-121 |
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Canadian Journal of Earth Sciences |
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16 |
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7 |
container_start_page |
1341 |
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1361 |
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