Four North American glaciers advanced past their modern positions thousands of years apart in the Holocene
There is unambiguous evidence that glaciers have retreated from their 19th century positions, but it is less clear how far glaciers have retreated relative to their long-term Holocene fluctuations. Glaciers in western North America are thought to have advanced from minimum positions in the Early Hol...
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Copernicus Publications
2023
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ftdoajarticles:oai:doaj.org/article:041669e0ced74dd08408f1b09db498c1 2024-01-21T10:06:26+01:00 Four North American glaciers advanced past their modern positions thousands of years apart in the Holocene A. G. Jones S. A. Marcott A. L. Gorin T. M. Kennedy J. D. Shakun B. M. Goehring B. Menounos D. H. Clark M. Romero M. W. Caffee 2023-12-01T00:00:00Z https://doi.org/10.5194/tc-17-5459-2023 https://doaj.org/article/041669e0ced74dd08408f1b09db498c1 EN eng Copernicus Publications https://tc.copernicus.org/articles/17/5459/2023/tc-17-5459-2023.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-17-5459-2023 1994-0416 1994-0424 https://doaj.org/article/041669e0ced74dd08408f1b09db498c1 The Cryosphere, Vol 17, Pp 5459-5475 (2023) Environmental sciences GE1-350 Geology QE1-996.5 article 2023 ftdoajarticles https://doi.org/10.5194/tc-17-5459-2023 2023-12-24T01:41:12Z There is unambiguous evidence that glaciers have retreated from their 19th century positions, but it is less clear how far glaciers have retreated relative to their long-term Holocene fluctuations. Glaciers in western North America are thought to have advanced from minimum positions in the Early Holocene to maximum positions in the Late Holocene. We assess when four North American glaciers, located between 38–60 ∘ N, were larger or smaller than their modern (2018–2020 CE) positions during the Holocene. We measured 26 paired cosmogenic in situ 14 C and 10 Be concentrations in recently exposed proglacial bedrock and applied a Monte Carlo forward model to reconstruct plausible bedrock exposure–burial histories. We find that these glaciers advanced past their modern positions thousands of years apart in the Holocene: a glacier in the Juneau Icefield (BC, Canada) at ∼2 ka, Kokanee Glacier (BC, Canada) at ∼6 ka, and Mammoth Glacier (WY, USA) at ∼1 ka; the fourth glacier, Conness Glacier (CA, USA), was likely larger than its modern position for the duration of the Holocene until present. The disparate Holocene exposure–burial histories are at odds with expectations of similar glacier histories given the presumed shared climate forcings of decreasing Northern Hemisphere summer insolation through the Holocene followed by global greenhouse gas forcing in the industrial era. We hypothesize that the range in histories is the result of unequal amounts of modern retreat relative to each glacier's Holocene maximum position, rather than asynchronous Holocene advance histories. We explore the influence of glacier hypsometry and response time on glacier retreat in the industrial era as a potential cause of the non-uniform burial durations. We also report mean abrasion rates at three of the four glaciers: Juneau Icefield Glacier ( 0.3±0.3 mm yr −1 ), Kokanee Glacier ( 0.04±0.03 mm yr −1 ), and Mammoth Glacier ( 0.2±0.2 mm yr −1 ). Article in Journal/Newspaper glacier* The Cryosphere Directory of Open Access Journals: DOAJ Articles Canada Juneau Icefield ENVELOPE(-134.254,-134.254,58.916,58.916) The Cryosphere 17 12 5459 5475 |
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 A. G. Jones S. A. Marcott A. L. Gorin T. M. Kennedy J. D. Shakun B. M. Goehring B. Menounos D. H. Clark M. Romero M. W. Caffee Four North American glaciers advanced past their modern positions thousands of years apart in the Holocene |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
There is unambiguous evidence that glaciers have retreated from their 19th century positions, but it is less clear how far glaciers have retreated relative to their long-term Holocene fluctuations. Glaciers in western North America are thought to have advanced from minimum positions in the Early Holocene to maximum positions in the Late Holocene. We assess when four North American glaciers, located between 38–60 ∘ N, were larger or smaller than their modern (2018–2020 CE) positions during the Holocene. We measured 26 paired cosmogenic in situ 14 C and 10 Be concentrations in recently exposed proglacial bedrock and applied a Monte Carlo forward model to reconstruct plausible bedrock exposure–burial histories. We find that these glaciers advanced past their modern positions thousands of years apart in the Holocene: a glacier in the Juneau Icefield (BC, Canada) at ∼2 ka, Kokanee Glacier (BC, Canada) at ∼6 ka, and Mammoth Glacier (WY, USA) at ∼1 ka; the fourth glacier, Conness Glacier (CA, USA), was likely larger than its modern position for the duration of the Holocene until present. The disparate Holocene exposure–burial histories are at odds with expectations of similar glacier histories given the presumed shared climate forcings of decreasing Northern Hemisphere summer insolation through the Holocene followed by global greenhouse gas forcing in the industrial era. We hypothesize that the range in histories is the result of unequal amounts of modern retreat relative to each glacier's Holocene maximum position, rather than asynchronous Holocene advance histories. We explore the influence of glacier hypsometry and response time on glacier retreat in the industrial era as a potential cause of the non-uniform burial durations. We also report mean abrasion rates at three of the four glaciers: Juneau Icefield Glacier ( 0.3±0.3 mm yr −1 ), Kokanee Glacier ( 0.04±0.03 mm yr −1 ), and Mammoth Glacier ( 0.2±0.2 mm yr −1 ). |
format |
Article in Journal/Newspaper |
author |
A. G. Jones S. A. Marcott A. L. Gorin T. M. Kennedy J. D. Shakun B. M. Goehring B. Menounos D. H. Clark M. Romero M. W. Caffee |
author_facet |
A. G. Jones S. A. Marcott A. L. Gorin T. M. Kennedy J. D. Shakun B. M. Goehring B. Menounos D. H. Clark M. Romero M. W. Caffee |
author_sort |
A. G. Jones |
title |
Four North American glaciers advanced past their modern positions thousands of years apart in the Holocene |
title_short |
Four North American glaciers advanced past their modern positions thousands of years apart in the Holocene |
title_full |
Four North American glaciers advanced past their modern positions thousands of years apart in the Holocene |
title_fullStr |
Four North American glaciers advanced past their modern positions thousands of years apart in the Holocene |
title_full_unstemmed |
Four North American glaciers advanced past their modern positions thousands of years apart in the Holocene |
title_sort |
four north american glaciers advanced past their modern positions thousands of years apart in the holocene |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/tc-17-5459-2023 https://doaj.org/article/041669e0ced74dd08408f1b09db498c1 |
long_lat |
ENVELOPE(-134.254,-134.254,58.916,58.916) |
geographic |
Canada Juneau Icefield |
geographic_facet |
Canada Juneau Icefield |
genre |
glacier* The Cryosphere |
genre_facet |
glacier* The Cryosphere |
op_source |
The Cryosphere, Vol 17, Pp 5459-5475 (2023) |
op_relation |
https://tc.copernicus.org/articles/17/5459/2023/tc-17-5459-2023.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-17-5459-2023 1994-0416 1994-0424 https://doaj.org/article/041669e0ced74dd08408f1b09db498c1 |
op_doi |
https://doi.org/10.5194/tc-17-5459-2023 |
container_title |
The Cryosphere |
container_volume |
17 |
container_issue |
12 |
container_start_page |
5459 |
op_container_end_page |
5475 |
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1788696886543122432 |