The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10 Be exposure dating
Deglaciation of the northwestern Laurentide Ice Sheet in the central Mackenzie Valley opened the northern portion of the deglacial Ice-Free Corridor between the Laurentide and Cordilleran ice sheets and a drainage route to the Arctic Ocean. In addition, ice sheet saddle collapse in this section of t...
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2022
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ftdoajarticles:oai:doaj.org/article:069d12d51c514897836504a04f7b346a 2023-05-15T14:59:59+02:00 The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10 Be exposure dating B. J. Stoker M. Margold J. C. Gosse A. J. Hidy A. J. Monteath J. M. Young N. Gandy L. J. Gregoire S. L. Norris D. Froese 2022-12-01T00:00:00Z https://doi.org/10.5194/tc-16-4865-2022 https://doaj.org/article/069d12d51c514897836504a04f7b346a EN eng Copernicus Publications https://tc.copernicus.org/articles/16/4865/2022/tc-16-4865-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-4865-2022 1994-0416 1994-0424 https://doaj.org/article/069d12d51c514897836504a04f7b346a The Cryosphere, Vol 16, Pp 4865-4886 (2022) Environmental sciences GE1-350 Geology QE1-996.5 article 2022 ftdoajarticles https://doi.org/10.5194/tc-16-4865-2022 2022-12-30T21:06:17Z Deglaciation of the northwestern Laurentide Ice Sheet in the central Mackenzie Valley opened the northern portion of the deglacial Ice-Free Corridor between the Laurentide and Cordilleran ice sheets and a drainage route to the Arctic Ocean. In addition, ice sheet saddle collapse in this section of the Laurentide Ice Sheet has been implicated as a mechanism for delivering substantial freshwater influx into the Arctic Ocean on centennial timescales. However, there is little empirical data to constrain the deglaciation chronology in the central Mackenzie Valley where the northern slopes of the ice saddle were located. Here, we present 30 new 10 Be cosmogenic nuclide exposure dates across six sites, including two elevation transects, which constrain the timing and rate of thinning and retreat of the Laurentide Ice Sheet in the area. Our new 10 Be dates indicate that the initial deglaciation of the eastern summits of the central Mackenzie Mountains began at ∼15.8 ka (17.1–14.6 ka), ∼1000 years earlier than in previous reconstructions. The main phase of ice saddle collapse occurred between ∼14.9 and 13.6 ka, consistent with numerical modelling simulations, placing this event within the Bølling–Allerød interval (14.6–12.9 ka). Our new dates require a revision of ice margin retreat dynamics, with ice retreating more easterly rather than southward along the Mackenzie Valley. In addition, we quantify a total sea level rise contribution from the Cordilleran–Laurentide ice saddle region of ∼11.2 m between 16 and 13 ka. Article in Journal/Newspaper Arctic Arctic Ocean Ice Sheet Mackenzie mountains Mackenzie Valley Northwest Territories The Cryosphere Directory of Open Access Journals: DOAJ Articles Arctic Arctic Ocean Northwest Territories Canada Mackenzie Valley ENVELOPE(-126.070,-126.070,52.666,52.666) The Cryosphere 16 12 4865 4886 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 B. J. Stoker M. Margold J. C. Gosse A. J. Hidy A. J. Monteath J. M. Young N. Gandy L. J. Gregoire S. L. Norris D. Froese The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10 Be exposure dating |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Deglaciation of the northwestern Laurentide Ice Sheet in the central Mackenzie Valley opened the northern portion of the deglacial Ice-Free Corridor between the Laurentide and Cordilleran ice sheets and a drainage route to the Arctic Ocean. In addition, ice sheet saddle collapse in this section of the Laurentide Ice Sheet has been implicated as a mechanism for delivering substantial freshwater influx into the Arctic Ocean on centennial timescales. However, there is little empirical data to constrain the deglaciation chronology in the central Mackenzie Valley where the northern slopes of the ice saddle were located. Here, we present 30 new 10 Be cosmogenic nuclide exposure dates across six sites, including two elevation transects, which constrain the timing and rate of thinning and retreat of the Laurentide Ice Sheet in the area. Our new 10 Be dates indicate that the initial deglaciation of the eastern summits of the central Mackenzie Mountains began at ∼15.8 ka (17.1–14.6 ka), ∼1000 years earlier than in previous reconstructions. The main phase of ice saddle collapse occurred between ∼14.9 and 13.6 ka, consistent with numerical modelling simulations, placing this event within the Bølling–Allerød interval (14.6–12.9 ka). Our new dates require a revision of ice margin retreat dynamics, with ice retreating more easterly rather than southward along the Mackenzie Valley. In addition, we quantify a total sea level rise contribution from the Cordilleran–Laurentide ice saddle region of ∼11.2 m between 16 and 13 ka. |
format |
Article in Journal/Newspaper |
author |
B. J. Stoker M. Margold J. C. Gosse A. J. Hidy A. J. Monteath J. M. Young N. Gandy L. J. Gregoire S. L. Norris D. Froese |
author_facet |
B. J. Stoker M. Margold J. C. Gosse A. J. Hidy A. J. Monteath J. M. Young N. Gandy L. J. Gregoire S. L. Norris D. Froese |
author_sort |
B. J. Stoker |
title |
The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10 Be exposure dating |
title_short |
The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10 Be exposure dating |
title_full |
The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10 Be exposure dating |
title_fullStr |
The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10 Be exposure dating |
title_full_unstemmed |
The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10 Be exposure dating |
title_sort |
collapse of the cordilleran–laurentide ice saddle and early opening of the mackenzie valley, northwest territories, canada, constrained by 10 be exposure dating |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-4865-2022 https://doaj.org/article/069d12d51c514897836504a04f7b346a |
long_lat |
ENVELOPE(-126.070,-126.070,52.666,52.666) |
geographic |
Arctic Arctic Ocean Northwest Territories Canada Mackenzie Valley |
geographic_facet |
Arctic Arctic Ocean Northwest Territories Canada Mackenzie Valley |
genre |
Arctic Arctic Ocean Ice Sheet Mackenzie mountains Mackenzie Valley Northwest Territories The Cryosphere |
genre_facet |
Arctic Arctic Ocean Ice Sheet Mackenzie mountains Mackenzie Valley Northwest Territories The Cryosphere |
op_source |
The Cryosphere, Vol 16, Pp 4865-4886 (2022) |
op_relation |
https://tc.copernicus.org/articles/16/4865/2022/tc-16-4865-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-4865-2022 1994-0416 1994-0424 https://doaj.org/article/069d12d51c514897836504a04f7b346a |
op_doi |
https://doi.org/10.5194/tc-16-4865-2022 |
container_title |
The Cryosphere |
container_volume |
16 |
container_issue |
12 |
container_start_page |
4865 |
op_container_end_page |
4886 |
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1766332096926711808 |