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...

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Published in:The Cryosphere
Main Authors: Stoker, Benjamin J., Margold, Martin, Gosse, John C., Hidy, Alan J., Monteath, Alistair J., Young, Joseph M., Gandy, Niall, Gregoire, Lauren J., Norris, Sophie L., Froese, Duane
Format: Article in Journal/Newspaper
Language:English
Published: The Cryosphere 2022
Subjects:
Online Access:http://hdl.handle.net/1828/14691
https://doi.org/10.5194/tc-16-4865-2022
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spelling ftuvicpubl:oai:dspace.library.uvic.ca:1828/14691 2023-05-15T15:02:05+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 Stoker, Benjamin J. Margold, Martin Gosse, John C. Hidy, Alan J. Monteath, Alistair J. Young, Joseph M. Gandy, Niall Gregoire, Lauren J. Norris, Sophie L. Froese, Duane 2022 application/pdf http://hdl.handle.net/1828/14691 https://doi.org/10.5194/tc-16-4865-2022 en eng The Cryosphere Stoker, B. J., Margold, M., Gosse, J. C., Hidy, A. J., Monteath, A. J., Young, J. M., . . . Froese, D. (2022). “The collapse of the Cordilleran-Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10Be exposure dating.” The Cryosphere, 16, 4865-4886. https://doi.org/10.5195/tc- 16-4865-2022 https://doi.org/10.5194/tc-16-4865-2022 http://hdl.handle.net/1828/14691 Article 2022 ftuvicpubl https://doi.org/10.5194/tc-16-4865-2022 https://doi.org/10.5195/tc 2023-02-01T00:45:30Z 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 ~ 11:2m between 16 and 13 ka. This research was supported by the Czech Science Foundation (grant no. 19-21216Y), the Swedish Research Council International Postdoctoral Fellowship (grant no. 637-2014- 483) awarded to Martin Margold, the Charles University Grant Agency project (GAUK project no. 122220) awarded to Benjamin J. Stoker, grants from the NRCan Polar Continental Shelf Program and the Natural Science and Engineering Research Council awarded to Duane Froese, and grants from the University of Alberta Northern Research Awards ... Article in Journal/Newspaper Arctic Arctic Ocean Ice Sheet Mackenzie mountains Mackenzie Valley Northwest Territories The Cryosphere University of Victoria (Canada): UVicDSpace 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 University of Victoria (Canada): UVicDSpace
op_collection_id ftuvicpubl
language English
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 ~ 11:2m between 16 and 13 ka. This research was supported by the Czech Science Foundation (grant no. 19-21216Y), the Swedish Research Council International Postdoctoral Fellowship (grant no. 637-2014- 483) awarded to Martin Margold, the Charles University Grant Agency project (GAUK project no. 122220) awarded to Benjamin J. Stoker, grants from the NRCan Polar Continental Shelf Program and the Natural Science and Engineering Research Council awarded to Duane Froese, and grants from the University of Alberta Northern Research Awards ...
format Article in Journal/Newspaper
author Stoker, Benjamin J.
Margold, Martin
Gosse, John C.
Hidy, Alan J.
Monteath, Alistair J.
Young, Joseph M.
Gandy, Niall
Gregoire, Lauren J.
Norris, Sophie L.
Froese, Duane
spellingShingle Stoker, Benjamin J.
Margold, Martin
Gosse, John C.
Hidy, Alan J.
Monteath, Alistair J.
Young, Joseph M.
Gandy, Niall
Gregoire, Lauren J.
Norris, Sophie L.
Froese, Duane
The collapse of the Cordilleran-Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10Be exposure dating
author_facet Stoker, Benjamin J.
Margold, Martin
Gosse, John C.
Hidy, Alan J.
Monteath, Alistair J.
Young, Joseph M.
Gandy, Niall
Gregoire, Lauren J.
Norris, Sophie L.
Froese, Duane
author_sort Stoker, Benjamin J.
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 The Cryosphere
publishDate 2022
url http://hdl.handle.net/1828/14691
https://doi.org/10.5194/tc-16-4865-2022
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_relation Stoker, B. J., Margold, M., Gosse, J. C., Hidy, A. J., Monteath, A. J., Young, J. M., . . . Froese, D. (2022). “The collapse of the Cordilleran-Laurentide ice saddle and early opening of the Mackenzie Valley, Northwest Territories, Canada, constrained by 10Be exposure dating.” The Cryosphere, 16, 4865-4886. https://doi.org/10.5195/tc- 16-4865-2022
https://doi.org/10.5194/tc-16-4865-2022
http://hdl.handle.net/1828/14691
op_doi https://doi.org/10.5194/tc-16-4865-2022
https://doi.org/10.5195/tc
container_title The Cryosphere
container_volume 16
container_issue 12
container_start_page 4865
op_container_end_page 4886
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