Progressive formation of modern drumlins at Múlajökull, Iceland: stratigraphical and morphological evidence
The drumlin field at Múlajökull, Iceland, is considered to be an active field in that partly and fully ice-covered drumlins are being shaped by the current glacier regime. We test the hypothesis that the drumlins form by a combination of erosion and deposition during successive surge cycles. We mapp...
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ftiowastateuniv:oai:lib.dr.iastate.edu:ge_at_pubs-1306 2023-05-15T16:21:40+02:00 Progressive formation of modern drumlins at Múlajökull, Iceland: stratigraphical and morphological evidence Benediktsson, Ívar Örn Jónsson, Sverrir A. Schomacker, Anders Johnson, Mark D. Ingólfsson, Ólafur Zoet, Lucas Iverson, Neal R. Stötter, Johann 2016-10-01T07:00:00Z application/pdf https://lib.dr.iastate.edu/ge_at_pubs/294 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1306&context=ge_at_pubs en eng Iowa State University Digital Repository https://lib.dr.iastate.edu/ge_at_pubs/294 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1306&context=ge_at_pubs Geological and Atmospheric Sciences Publications Geology Geomorphology Glaciology Spatial Science text 2016 ftiowastateuniv 2020-06-27T22:42:07Z The drumlin field at Múlajökull, Iceland, is considered to be an active field in that partly and fully ice-covered drumlins are being shaped by the current glacier regime. We test the hypothesis that the drumlins form by a combination of erosion and deposition during successive surge cycles. We mapped and measured 143 drumlins and studied their stratigraphy in four exposures. All exposures reveal several till units where the youngest till commonly truncates older tills on the drumlin flanks and proximal slope. Drumlins inside a 1992 moraine are relatively long and narrow whereas drumlins outside the moraine are wider and shorter. A conceptual model suggests that radial crevasses create spatial heterogeneity in normal stress on the bed so that deposition is favoured beneath crevasses and erosion in adjacent areas. Consequently, the crevasse pattern of the glacier controls the location of proto drumlins. A feedback mechanism leads to continued crevassing and increased sedimentation at the location of the proto-drumlins. Drumlin relief and elongation ratio increases as the glacier erodes the sides and drapes a new till over the landform through successive surges. Our observations of this only known active drumlin field may have implications for the formation and morphological evolution of Pleistocene drumlin fields with similar composition, and our model may be tested on modern drumlins that may become exposed upon future ice retreat. Text glacier Iceland Digital Repository @ Iowa State University |
institution |
Open Polar |
collection |
Digital Repository @ Iowa State University |
op_collection_id |
ftiowastateuniv |
language |
English |
topic |
Geology Geomorphology Glaciology Spatial Science |
spellingShingle |
Geology Geomorphology Glaciology Spatial Science Benediktsson, Ívar Örn Jónsson, Sverrir A. Schomacker, Anders Johnson, Mark D. Ingólfsson, Ólafur Zoet, Lucas Iverson, Neal R. Stötter, Johann Progressive formation of modern drumlins at Múlajökull, Iceland: stratigraphical and morphological evidence |
topic_facet |
Geology Geomorphology Glaciology Spatial Science |
description |
The drumlin field at Múlajökull, Iceland, is considered to be an active field in that partly and fully ice-covered drumlins are being shaped by the current glacier regime. We test the hypothesis that the drumlins form by a combination of erosion and deposition during successive surge cycles. We mapped and measured 143 drumlins and studied their stratigraphy in four exposures. All exposures reveal several till units where the youngest till commonly truncates older tills on the drumlin flanks and proximal slope. Drumlins inside a 1992 moraine are relatively long and narrow whereas drumlins outside the moraine are wider and shorter. A conceptual model suggests that radial crevasses create spatial heterogeneity in normal stress on the bed so that deposition is favoured beneath crevasses and erosion in adjacent areas. Consequently, the crevasse pattern of the glacier controls the location of proto drumlins. A feedback mechanism leads to continued crevassing and increased sedimentation at the location of the proto-drumlins. Drumlin relief and elongation ratio increases as the glacier erodes the sides and drapes a new till over the landform through successive surges. Our observations of this only known active drumlin field may have implications for the formation and morphological evolution of Pleistocene drumlin fields with similar composition, and our model may be tested on modern drumlins that may become exposed upon future ice retreat. |
format |
Text |
author |
Benediktsson, Ívar Örn Jónsson, Sverrir A. Schomacker, Anders Johnson, Mark D. Ingólfsson, Ólafur Zoet, Lucas Iverson, Neal R. Stötter, Johann |
author_facet |
Benediktsson, Ívar Örn Jónsson, Sverrir A. Schomacker, Anders Johnson, Mark D. Ingólfsson, Ólafur Zoet, Lucas Iverson, Neal R. Stötter, Johann |
author_sort |
Benediktsson, Ívar Örn |
title |
Progressive formation of modern drumlins at Múlajökull, Iceland: stratigraphical and morphological evidence |
title_short |
Progressive formation of modern drumlins at Múlajökull, Iceland: stratigraphical and morphological evidence |
title_full |
Progressive formation of modern drumlins at Múlajökull, Iceland: stratigraphical and morphological evidence |
title_fullStr |
Progressive formation of modern drumlins at Múlajökull, Iceland: stratigraphical and morphological evidence |
title_full_unstemmed |
Progressive formation of modern drumlins at Múlajökull, Iceland: stratigraphical and morphological evidence |
title_sort |
progressive formation of modern drumlins at múlajökull, iceland: stratigraphical and morphological evidence |
publisher |
Iowa State University Digital Repository |
publishDate |
2016 |
url |
https://lib.dr.iastate.edu/ge_at_pubs/294 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1306&context=ge_at_pubs |
genre |
glacier Iceland |
genre_facet |
glacier Iceland |
op_source |
Geological and Atmospheric Sciences Publications |
op_relation |
https://lib.dr.iastate.edu/ge_at_pubs/294 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1306&context=ge_at_pubs |
_version_ |
1766009661700440064 |