Basal processes beneath an Arctic glacier and their geomorphic imprint after a surge, Elisebreen, Svalbard
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Basal processes beneath an Arctic glacier and their geomorphic imprint after a surge, Elisebreen, Svalbard. / Christoffersen, Poul; Piotrowski, Jan A.; Larsen, Nicolaj K.
In: Quaternary Research, Vol. 64, No. 2, 2005, p. 125-137.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Basal processes beneath an Arctic glacier and their geomorphic imprint after a surge, Elisebreen, Svalbard
AU - Christoffersen, Poul
AU - Piotrowski, Jan A.
AU - Larsen, Nicolaj K.
PY - 2005
Y1 - 2005
N2 - The foreground of Elisebreen, a retreating valley glacier in West Svalbard, exhibits a well-preserved assemblage of subglacial landforms including ice-flow parallel ridges (flutings), ice-flow oblique ridges (crevasse-fill features), and meandering ridges (infill of basal meltwater conduits). Other landforms are thrust-block moraine, hummocky terrain, and drumlinoid hills. We argue in agreement with geomorphological models that this landform assemblage was generated by ice-flow instability, possibly a surge, which took place in the past when the ice was thicker and the bed warmer. The surge likely occurred due to elevated pore-water pressure in a thin layer of thawed and water-saturated till that separated glacier ice from a frozen substratum. Termination may have been caused by a combination of water drainage and loss of lubricating sediment. Sedimentological investigations indicate that key landforms may be formed by weak till oozing into basal cavities and crevasses, opening in response to accelerated ice flow, and into water conduits abandoned during rearrangement of the basal water system. Today, Elisebreen may no longer have surge potential due to its diminished size. The ability to identify ice-flow instability from geomorphological criteria is important in deglaciated terrain as well as in regions where ice dynamics are adapting to climate change.
AB - The foreground of Elisebreen, a retreating valley glacier in West Svalbard, exhibits a well-preserved assemblage of subglacial landforms including ice-flow parallel ridges (flutings), ice-flow oblique ridges (crevasse-fill features), and meandering ridges (infill of basal meltwater conduits). Other landforms are thrust-block moraine, hummocky terrain, and drumlinoid hills. We argue in agreement with geomorphological models that this landform assemblage was generated by ice-flow instability, possibly a surge, which took place in the past when the ice was thicker and the bed warmer. The surge likely occurred due to elevated pore-water pressure in a thin layer of thawed and water-saturated till that separated glacier ice from a frozen substratum. Termination may have been caused by a combination of water drainage and loss of lubricating sediment. Sedimentological investigations indicate that key landforms may be formed by weak till oozing into basal cavities and crevasses, opening in response to accelerated ice flow, and into water conduits abandoned during rearrangement of the basal water system. Today, Elisebreen may no longer have surge potential due to its diminished size. The ability to identify ice-flow instability from geomorphological criteria is important in deglaciated terrain as well as in regions where ice dynamics are adapting to climate change.
KW - Flutings
KW - Landforms
KW - Subglacial processes
KW - Surge
KW - Svalbard
KW - Till
U2 - 10.1016/j.yqres.2005.05.009
DO - 10.1016/j.yqres.2005.05.009
M3 - Journal article
AN - SCOPUS:24144481790
VL - 64
SP - 125
EP - 137
JO - Quaternary Research
JF - Quaternary Research
SN - 0033-5894
IS - 2
ER -
ID: 235142713