The permafrost regime in the Mackenzie Delta, Beaufort Sea region, N.W.T. and its significance to the reconstruction of the palaeoclimatic history
Abstract Observed depths to the base of the ice‐bearing permafrost (!BPF) as determined from geophysical well‐log and survey information in the Mackenzie Delta and offshore Beaufort Sea continental shelf show significant variation. Depths range from over 700m beneath the northeastern portion of Rich...
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crwiley:10.1002/jqs.3390030103 2024-06-23T07:51:40+00:00 The permafrost regime in the Mackenzie Delta, Beaufort Sea region, N.W.T. and its significance to the reconstruction of the palaeoclimatic history Allen, Diana M. Michel, Frederick A. Judge, Alan S. 1988 http://dx.doi.org/10.1002/jqs.3390030103 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjqs.3390030103 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jqs.3390030103 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Quaternary Science volume 3, issue 1, page 3-13 ISSN 0267-8179 1099-1417 journal-article 1988 crwiley https://doi.org/10.1002/jqs.3390030103 2024-06-04T06:45:55Z Abstract Observed depths to the base of the ice‐bearing permafrost (!BPF) as determined from geophysical well‐log and survey information in the Mackenzie Delta and offshore Beaufort Sea continental shelf show significant variation. Depths range from over 700m beneath the northeastern portion of Richards Island and the adjacent offshore region to the north, to less than 100m in the modern Mackenzie Delta and offshore Mackenzie Bay regions. Along the Tuktoyaktuk Peninsula, permafrost thicknesses exceed 600m but tend to thin to less than 100m in a southeasterly direction. The wide variation in the thickness and distribution of permafrost is due in part to differences in the subsurface deltaic lithologies and to the complexity of the past surface temperature history, exhibited, for example, by fluctuations of the mean annual ground temperature. Geological cross‐sections showing variation in the Tertiary and Upper Cretaceous deltaic sequences indicate a good correlation with the permafrost distribution. In particular, where the sand and gravel units of the Iperk and Kugmallit Sequences predominate, permafrost is thick owing to the high thermal conductivities of the ice‐rich sediments. Conversely, where the low thermal conductivity shales and mudstones of the Richards Sequence are present, permafrost is accordingly thinner. Numerical models of permafrost aggradation in the Mackenzie Delta region suggest that Early and Late Wisconsinan surface temperatures were of the order −18°C. A mid‐Wisconsinan rise in temperature to approximately −8°C, similar to mean surface temperature today, is also indicated. This proposed palaeoclimate is sufficient to account for the observed maximum permafrost thicknesses in the region. Article in Journal/Newspaper Beaufort Sea Ice Mackenzie Bay Mackenzie Delta permafrost Richards Island Wiley Online Library Mackenzie Bay ENVELOPE(70.583,70.583,-68.617,-68.617) Mackenzie Delta ENVELOPE(-136.672,-136.672,68.833,68.833) Tuktoyaktuk ENVELOPE(-133.006,-133.006,69.425,69.425) Tuktoyaktuk Peninsula ENVELOPE(-131.339,-131.339,69.750,69.750) Journal of Quaternary Science 3 1 3 13 |
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Open Polar |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract Observed depths to the base of the ice‐bearing permafrost (!BPF) as determined from geophysical well‐log and survey information in the Mackenzie Delta and offshore Beaufort Sea continental shelf show significant variation. Depths range from over 700m beneath the northeastern portion of Richards Island and the adjacent offshore region to the north, to less than 100m in the modern Mackenzie Delta and offshore Mackenzie Bay regions. Along the Tuktoyaktuk Peninsula, permafrost thicknesses exceed 600m but tend to thin to less than 100m in a southeasterly direction. The wide variation in the thickness and distribution of permafrost is due in part to differences in the subsurface deltaic lithologies and to the complexity of the past surface temperature history, exhibited, for example, by fluctuations of the mean annual ground temperature. Geological cross‐sections showing variation in the Tertiary and Upper Cretaceous deltaic sequences indicate a good correlation with the permafrost distribution. In particular, where the sand and gravel units of the Iperk and Kugmallit Sequences predominate, permafrost is thick owing to the high thermal conductivities of the ice‐rich sediments. Conversely, where the low thermal conductivity shales and mudstones of the Richards Sequence are present, permafrost is accordingly thinner. Numerical models of permafrost aggradation in the Mackenzie Delta region suggest that Early and Late Wisconsinan surface temperatures were of the order −18°C. A mid‐Wisconsinan rise in temperature to approximately −8°C, similar to mean surface temperature today, is also indicated. This proposed palaeoclimate is sufficient to account for the observed maximum permafrost thicknesses in the region. |
format |
Article in Journal/Newspaper |
author |
Allen, Diana M. Michel, Frederick A. Judge, Alan S. |
spellingShingle |
Allen, Diana M. Michel, Frederick A. Judge, Alan S. The permafrost regime in the Mackenzie Delta, Beaufort Sea region, N.W.T. and its significance to the reconstruction of the palaeoclimatic history |
author_facet |
Allen, Diana M. Michel, Frederick A. Judge, Alan S. |
author_sort |
Allen, Diana M. |
title |
The permafrost regime in the Mackenzie Delta, Beaufort Sea region, N.W.T. and its significance to the reconstruction of the palaeoclimatic history |
title_short |
The permafrost regime in the Mackenzie Delta, Beaufort Sea region, N.W.T. and its significance to the reconstruction of the palaeoclimatic history |
title_full |
The permafrost regime in the Mackenzie Delta, Beaufort Sea region, N.W.T. and its significance to the reconstruction of the palaeoclimatic history |
title_fullStr |
The permafrost regime in the Mackenzie Delta, Beaufort Sea region, N.W.T. and its significance to the reconstruction of the palaeoclimatic history |
title_full_unstemmed |
The permafrost regime in the Mackenzie Delta, Beaufort Sea region, N.W.T. and its significance to the reconstruction of the palaeoclimatic history |
title_sort |
permafrost regime in the mackenzie delta, beaufort sea region, n.w.t. and its significance to the reconstruction of the palaeoclimatic history |
publisher |
Wiley |
publishDate |
1988 |
url |
http://dx.doi.org/10.1002/jqs.3390030103 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjqs.3390030103 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jqs.3390030103 |
long_lat |
ENVELOPE(70.583,70.583,-68.617,-68.617) ENVELOPE(-136.672,-136.672,68.833,68.833) ENVELOPE(-133.006,-133.006,69.425,69.425) ENVELOPE(-131.339,-131.339,69.750,69.750) |
geographic |
Mackenzie Bay Mackenzie Delta Tuktoyaktuk Tuktoyaktuk Peninsula |
geographic_facet |
Mackenzie Bay Mackenzie Delta Tuktoyaktuk Tuktoyaktuk Peninsula |
genre |
Beaufort Sea Ice Mackenzie Bay Mackenzie Delta permafrost Richards Island |
genre_facet |
Beaufort Sea Ice Mackenzie Bay Mackenzie Delta permafrost Richards Island |
op_source |
Journal of Quaternary Science volume 3, issue 1, page 3-13 ISSN 0267-8179 1099-1417 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/jqs.3390030103 |
container_title |
Journal of Quaternary Science |
container_volume |
3 |
container_issue |
1 |
container_start_page |
3 |
op_container_end_page |
13 |
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1802642790586253312 |