Rapid retreat of the southwestern Laurentide Ice Sheet during the Bølling-Allerød interval
Rapid retreat of the southwestern Laurentide Ice Sheet during the Bølling-Allerød interval
The timing of Laurentide Ice Sheet deglaciation along its southwestern margin controlled the evolution of large glacial lakes and has implications for human migration into the Americas. Accurate reconstruction of the ice sheet’s retreat also constrains glacial isostatic adjustment models and is important for understanding ice-sheet sensitivity to climate forcing. Despite its significance, retreat of the southwestern Laurentide Ice Sheet (SWLIS) is poorly constrained by minimum-limiting 14C data. We present 26 new cosmogenic
10Be exposure ages spanning the western Interior Plains, Canada. Using a Bayesian framework, we combine these data with geomorphic mapping,
10Be, and high-quality minimum-limiting
14C ages to provide an updated chronology. This dataset presents an internally consistent retreat record and indicates that the initial detachment of the SWLIS from its convergence with the Cordilleran Ice Sheet began by ca. 15.0 ka, concurrent with or slightly prior to the onset of the Bølling-Allerød interval (14.7–12.9 ka) and retreated >1200 km to its Younger Dryas (YD) position in ~2500 yr. Ice-sheet stabilization at the Cree Lake Moraine facilitated a meltwater drainage route to the Arctic from glacial Lake Agassiz within the YD, but not necessarily at the beginning. Our record of deglaciation and new YD constraints demonstrate deglaciation of the Interior Plains was ~60% faster than suggested by minimum
14C constraints alone. Numerical modeling of this rapid retreat estimates a loss of ~3.7 m of sea-level equivalent from the SWLIS during the Bølling-Allerød interval
417-421
Norris, Sophie L.
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Tarasov, Lev
293bb3c1-efd5-4497-b5e3-ed2261cf1fd1
Monteath, Alistair J.
d9499e7f-b5d9-48ad-87d8-3c2a74e40fa9
Gosse, John C.
b52a1c61-58d6-4286-a522-4c9b1584348e
Hidy, Alan J.
e7471681-3aa6-4ed3-b1f3-5ce6dcc92372
Margold, Martin
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Froese, Duane G.
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1 April 2022
Norris, Sophie L.
fde61661-7668-4854-84ff-75d4916d87eb
Tarasov, Lev
293bb3c1-efd5-4497-b5e3-ed2261cf1fd1
Monteath, Alistair J.
d9499e7f-b5d9-48ad-87d8-3c2a74e40fa9
Gosse, John C.
b52a1c61-58d6-4286-a522-4c9b1584348e
Hidy, Alan J.
e7471681-3aa6-4ed3-b1f3-5ce6dcc92372
Margold, Martin
4b9a59fe-b2c9-4573-994e-ff3bd583c899
Froese, Duane G.
98896463-a7fe-462a-badb-9e9732b49503
Norris, Sophie L., Tarasov, Lev, Monteath, Alistair J., Gosse, John C., Hidy, Alan J., Margold, Martin and Froese, Duane G.
(2022)
Rapid retreat of the southwestern Laurentide Ice Sheet during the Bølling-Allerød interval.
Geology, 50 (4), .
(doi:10.1130/G49493.1).
Abstract
The timing of Laurentide Ice Sheet deglaciation along its southwestern margin controlled the evolution of large glacial lakes and has implications for human migration into the Americas. Accurate reconstruction of the ice sheet’s retreat also constrains glacial isostatic adjustment models and is important for understanding ice-sheet sensitivity to climate forcing. Despite its significance, retreat of the southwestern Laurentide Ice Sheet (SWLIS) is poorly constrained by minimum-limiting 14C data. We present 26 new cosmogenic
10Be exposure ages spanning the western Interior Plains, Canada. Using a Bayesian framework, we combine these data with geomorphic mapping,
10Be, and high-quality minimum-limiting
14C ages to provide an updated chronology. This dataset presents an internally consistent retreat record and indicates that the initial detachment of the SWLIS from its convergence with the Cordilleran Ice Sheet began by ca. 15.0 ka, concurrent with or slightly prior to the onset of the Bølling-Allerød interval (14.7–12.9 ka) and retreated >1200 km to its Younger Dryas (YD) position in ~2500 yr. Ice-sheet stabilization at the Cree Lake Moraine facilitated a meltwater drainage route to the Arctic from glacial Lake Agassiz within the YD, but not necessarily at the beginning. Our record of deglaciation and new YD constraints demonstrate deglaciation of the Interior Plains was ~60% faster than suggested by minimum
14C constraints alone. Numerical modeling of this rapid retreat estimates a loss of ~3.7 m of sea-level equivalent from the SWLIS during the Bølling-Allerød interval
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More information
Accepted/In Press date: 11 October 2021
e-pub ahead of print date: 16 December 2021
Published date: 1 April 2022
Additional Information:
Funding Information:
This research was funded by the Natural Sciences and Engineering Research Council of Canada (D.G. Froese, J.C. Gosse, and L. Tarasov) and the Canada Research Chair Program (D.G. Froese). Numerical simulations were completed using the ACEnet supercomputing cluster at Memorial University of Newfoundland. We thank G. Yang for BeO target chemistry; B. Menounos, J. England, A. Reyes, and N. Atkinson for comments on an early manuscript version; and D. Utting for suggesting erratic locations. This work was performed at Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. This is Lawrence Livermore National Laboratory contribution LLNL-JRNL-808330. We thank editor William Clyde and reviewers Martin Ross, James Teller, and an anonymous reviewer
Funding Information:
This research was funded by the Natural Sciences and Engineering Research Council of Canada (D.G. Froese, J.C. Gosse, and L. Tarasov) and the Canada Research Chair Program (D.G. Froese). Numerical simulations were completed using the ACEnet supercomputing cluster at Memorial University of Newfoundland. We thank G. Yang for BeO target chemistry; B. Menounos, J. England, A. Reyes, and N. Atkinson for comments on an early manuscript version; and D. Utting for suggesting erratic locations. This work was performed at Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. This is Lawrence Livermore National Laboratory contribution LLNL-JRNL-808330. We thank editor William Clyde and reviewers Martin Ross, James Teller, and an anonymous reviewer.
Publisher Copyright:
© 2022 Geological Society of America
Identifiers
Local EPrints ID: 472692
URI: http://eprints.soton.ac.uk/id/eprint/472692
ISSN: 0091-7613
PURE UUID: d8c4b38f-e083-428b-b0ae-4bc799dc04e6
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Date deposited: 14 Dec 2022 17:45
Last modified: 16 Mar 2024 23:15
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Contributors
Author:
Sophie L. Norris
Author:
Lev Tarasov
Author:
Alistair J. Monteath
Author:
John C. Gosse
Author:
Alan J. Hidy
Author:
Martin Margold
Author:
Duane G. Froese
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