The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10Be 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...
Published in: | The Cryosphere |
---|---|
Main Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2022
|
Subjects: | |
Online Access: | https://doi.org/10.5194/tc-16-4865-2022 https://tc.copernicus.org/articles/16/4865/2022/tc-16-4865-2022.pdf https://doaj.org/article/069d12d51c514897836504a04f7b346a |
id |
fttriple:oai:gotriple.eu:oai:doaj.org/article:069d12d51c514897836504a04f7b346a |
---|---|
record_format |
openpolar |
spelling |
fttriple:oai:gotriple.eu:oai:doaj.org/article:069d12d51c514897836504a04f7b346a 2023-05-15T14:59:50+02:00 The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10Be 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 2022-12-01 https://doi.org/10.5194/tc-16-4865-2022 https://tc.copernicus.org/articles/16/4865/2022/tc-16-4865-2022.pdf https://doaj.org/article/069d12d51c514897836504a04f7b346a en eng Copernicus Publications doi:10.5194/tc-16-4865-2022 1994-0416 1994-0424 https://tc.copernicus.org/articles/16/4865/2022/tc-16-4865-2022.pdf https://doaj.org/article/069d12d51c514897836504a04f7b346a undefined The Cryosphere, Vol 16, Pp 4865-4886 (2022) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2022 fttriple https://doi.org/10.5194/tc-16-4865-2022 2023-01-22T19:15:54Z 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 10Be 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 10Be 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 Unknown Arctic Arctic Ocean Canada Mackenzie Valley ENVELOPE(-126.070,-126.070,52.666,52.666) Northwest Territories The Cryosphere 16 12 4865 4886 |
institution |
Open Polar |
collection |
Unknown |
op_collection_id |
fttriple |
language |
English |
topic |
geo envir |
spellingShingle |
geo envir 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 10Be exposure dating |
topic_facet |
geo envir |
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 10Be 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 10Be 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 10Be exposure dating |
title_short |
The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10Be exposure dating |
title_full |
The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10Be exposure dating |
title_fullStr |
The collapse of the Cordilleran–Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10Be 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 10Be exposure dating |
title_sort |
collapse of the cordilleran–laurentide ice saddle and early opening of the mackenzie valley, northwest territories, canada, constrained by 10be exposure dating |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-4865-2022 https://tc.copernicus.org/articles/16/4865/2022/tc-16-4865-2022.pdf https://doaj.org/article/069d12d51c514897836504a04f7b346a |
long_lat |
ENVELOPE(-126.070,-126.070,52.666,52.666) |
geographic |
Arctic Arctic Ocean Canada Mackenzie Valley Northwest Territories |
geographic_facet |
Arctic Arctic Ocean Canada Mackenzie Valley Northwest Territories |
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 |
doi:10.5194/tc-16-4865-2022 1994-0416 1994-0424 https://tc.copernicus.org/articles/16/4865/2022/tc-16-4865-2022.pdf https://doaj.org/article/069d12d51c514897836504a04f7b346a |
op_rights |
undefined |
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 |
_version_ |
1766331950272872448 |