Permafrost at the ice base of recent pleistocene glaciations–inferences from borehole temperature profiles
Paleo-temperature reconstruction from precise depth (>2.0 km) well temperature logs can offer information on whether the bed of an ice sheet was frozen. Inversion or upward extrapolation of the >2-km-deep geothermal profile is the only method by which temperature evolution at the base of long-...
Main Author: | |
---|---|
Format: | Other/Unknown Material |
Language: | English |
Published: |
2012
|
Subjects: | |
Online Access: | https://era.library.ualberta.ca/items/d320cec2-16aa-4d80-ac8c-73a18636cb8f https://doi.org/10.7939/R3WS8HQ5X |
id |
ftunivalberta:oai:era.library.ualberta.ca:d320cec2-16aa-4d80-ac8c-73a18636cb8f |
---|---|
record_format |
openpolar |
spelling |
ftunivalberta:oai:era.library.ualberta.ca:d320cec2-16aa-4d80-ac8c-73a18636cb8f 2023-05-15T16:13:05+02:00 Permafrost at the ice base of recent pleistocene glaciations–inferences from borehole temperature profiles Majorowicz, J. 2012 https://era.library.ualberta.ca/items/d320cec2-16aa-4d80-ac8c-73a18636cb8f https://doi.org/10.7939/R3WS8HQ5X English eng https://era.library.ualberta.ca/items/d320cec2-16aa-4d80-ac8c-73a18636cb8f doi:10.7939/R3WS8HQ5X © 2012 Versita. This version of this article is open access and can be downloaded and shared. The original author(s) and source must be cited. Paleoclimate at last glaciation Permafrost under glacial Temperature profiles Paleopermafrost Article (Published) 2012 ftunivalberta https://doi.org/10.7939/R3WS8HQ5X 2022-08-22T20:14:05Z Paleo-temperature reconstruction from precise depth (>2.0 km) well temperature logs can offer information on whether the bed of an ice sheet was frozen. Inversion or upward extrapolation of the >2-km-deep geothermal profile is the only method by which temperature evolution at the base of long-disappeared ice sheets such as the Laurentide and Fennoscandian in the northern part of the Northern Hemisphere in North America and Europe can be inferred. It is obvious from the results from well temperature profiles that there were spatial variations in temperature at the base of the ice sheets during glaciations. This comes as no surprise, since modern-day measurements of temperature profiles through the ice of existing glaciers show a similarly large variability. Present bedrock temperatures measured beneath the central part of the Yukon Rusty glacier are near 0°C to –2°C while Greenland ice sheet base temperatures are –8 and –13°C. In case of very low paleo-temperatures derived from the interpretation of temperature profiles in the areas presently outside the current extent of glacial ice it can be shown that low temperature conditions under glacial ice could facilitate the existence of moderate (some 100–200 m) to thick (0.5 km–1 km) permafrost conditions. It is speculated here that, in many cases, paleo-glacial cold base ice could have existed right on top of paleopermafrost in sediments just below. Such ice-bonded permafrost may have been frozen to glacial ice above, forming pillars which fixed glacial ice to permafrost below, thus limiting ice movement in such places and resulting in the –extended persistence of permafrost. Other/Unknown Material Fennoscandian glacier Greenland Ice Ice Sheet permafrost Yukon University of Alberta: Era - Education and Research Archive Greenland Rusty Glacier ENVELOPE(-140.304,-140.304,61.199,61.199) Yukon |
institution |
Open Polar |
collection |
University of Alberta: Era - Education and Research Archive |
op_collection_id |
ftunivalberta |
language |
English |
topic |
Paleoclimate at last glaciation Permafrost under glacial Temperature profiles Paleopermafrost |
spellingShingle |
Paleoclimate at last glaciation Permafrost under glacial Temperature profiles Paleopermafrost Majorowicz, J. Permafrost at the ice base of recent pleistocene glaciations–inferences from borehole temperature profiles |
topic_facet |
Paleoclimate at last glaciation Permafrost under glacial Temperature profiles Paleopermafrost |
description |
Paleo-temperature reconstruction from precise depth (>2.0 km) well temperature logs can offer information on whether the bed of an ice sheet was frozen. Inversion or upward extrapolation of the >2-km-deep geothermal profile is the only method by which temperature evolution at the base of long-disappeared ice sheets such as the Laurentide and Fennoscandian in the northern part of the Northern Hemisphere in North America and Europe can be inferred. It is obvious from the results from well temperature profiles that there were spatial variations in temperature at the base of the ice sheets during glaciations. This comes as no surprise, since modern-day measurements of temperature profiles through the ice of existing glaciers show a similarly large variability. Present bedrock temperatures measured beneath the central part of the Yukon Rusty glacier are near 0°C to –2°C while Greenland ice sheet base temperatures are –8 and –13°C. In case of very low paleo-temperatures derived from the interpretation of temperature profiles in the areas presently outside the current extent of glacial ice it can be shown that low temperature conditions under glacial ice could facilitate the existence of moderate (some 100–200 m) to thick (0.5 km–1 km) permafrost conditions. It is speculated here that, in many cases, paleo-glacial cold base ice could have existed right on top of paleopermafrost in sediments just below. Such ice-bonded permafrost may have been frozen to glacial ice above, forming pillars which fixed glacial ice to permafrost below, thus limiting ice movement in such places and resulting in the –extended persistence of permafrost. |
format |
Other/Unknown Material |
author |
Majorowicz, J. |
author_facet |
Majorowicz, J. |
author_sort |
Majorowicz, J. |
title |
Permafrost at the ice base of recent pleistocene glaciations–inferences from borehole temperature profiles |
title_short |
Permafrost at the ice base of recent pleistocene glaciations–inferences from borehole temperature profiles |
title_full |
Permafrost at the ice base of recent pleistocene glaciations–inferences from borehole temperature profiles |
title_fullStr |
Permafrost at the ice base of recent pleistocene glaciations–inferences from borehole temperature profiles |
title_full_unstemmed |
Permafrost at the ice base of recent pleistocene glaciations–inferences from borehole temperature profiles |
title_sort |
permafrost at the ice base of recent pleistocene glaciations–inferences from borehole temperature profiles |
publishDate |
2012 |
url |
https://era.library.ualberta.ca/items/d320cec2-16aa-4d80-ac8c-73a18636cb8f https://doi.org/10.7939/R3WS8HQ5X |
long_lat |
ENVELOPE(-140.304,-140.304,61.199,61.199) |
geographic |
Greenland Rusty Glacier Yukon |
geographic_facet |
Greenland Rusty Glacier Yukon |
genre |
Fennoscandian glacier Greenland Ice Ice Sheet permafrost Yukon |
genre_facet |
Fennoscandian glacier Greenland Ice Ice Sheet permafrost Yukon |
op_relation |
https://era.library.ualberta.ca/items/d320cec2-16aa-4d80-ac8c-73a18636cb8f doi:10.7939/R3WS8HQ5X |
op_rights |
© 2012 Versita. This version of this article is open access and can be downloaded and shared. The original author(s) and source must be cited. |
op_doi |
https://doi.org/10.7939/R3WS8HQ5X |
_version_ |
1765998688153370624 |