Late Pleistocene glacial chronologies and paleoclimate in the northern Rocky Mountains
The geologic record of mountain glaciations is a robust indicator of terrestrial paleoclimate change. During the last glaciation, mountain ranges across the western U.S. hosted glaciers while the Cordilleran and Laurentide ice sheets flowed to the west and east of the continental divide, respectivel...
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ftcopernicus:oai:publications.copernicus.org:cpd96792 2023-05-15T16:40:33+02:00 Late Pleistocene glacial chronologies and paleoclimate in the northern Rocky Mountains Quirk, Brendon Huss, Elizabeth Laabs, Benjamin Leonard, Eric Licciardi, Joseph Plummer, Mitchell Caffee, Marc 2021-09-10 application/pdf https://doi.org/10.5194/cp-2021-106 https://cp.copernicus.org/preprints/cp-2021-106/ eng eng doi:10.5194/cp-2021-106 https://cp.copernicus.org/preprints/cp-2021-106/ eISSN: 1814-9332 Text 2021 ftcopernicus https://doi.org/10.5194/cp-2021-106 2021-09-13T16:22:27Z The geologic record of mountain glaciations is a robust indicator of terrestrial paleoclimate change. During the last glaciation, mountain ranges across the western U.S. hosted glaciers while the Cordilleran and Laurentide ice sheets flowed to the west and east of the continental divide, respectively. Records detailing the chronologies and paleoclimate significance of these ice advances have been developed for many sites across North America. However, relatively few glacial records have been developed for mountain glaciers in the northern Rocky Mountains near ice sheet margins. Here, we report cosmogenic beryllium-10 surface exposure ages and numerical glacier modeling results showing that mountain glaciers in the northern Rockies abandoned terminal moraines after the end of the Last Glacial Maximum around 17–18 ka and could have been sustained by −10 to −8.5 °C temperature depressions relative to modern assuming similar or drier than modern precipitation. Additionally, we present a deglacial chronology from the northern Rocky Mountains that indicates while there is considerable variability in initial moraine abandonment ages across the Rocky Mountains, the pace of subsequent ice retreat through the Lateglacial exhibits some regional coherence. Our results provide insight on potential regional mechanisms driving the initiation of and sustained deglaciation in the western U.S. including rising atmospheric CO 2 and ice sheet collapse. Text Ice Sheet Copernicus Publications: E-Journals Northern Rockies ENVELOPE(-123.446,-123.446,59.074,59.074) |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
The geologic record of mountain glaciations is a robust indicator of terrestrial paleoclimate change. During the last glaciation, mountain ranges across the western U.S. hosted glaciers while the Cordilleran and Laurentide ice sheets flowed to the west and east of the continental divide, respectively. Records detailing the chronologies and paleoclimate significance of these ice advances have been developed for many sites across North America. However, relatively few glacial records have been developed for mountain glaciers in the northern Rocky Mountains near ice sheet margins. Here, we report cosmogenic beryllium-10 surface exposure ages and numerical glacier modeling results showing that mountain glaciers in the northern Rockies abandoned terminal moraines after the end of the Last Glacial Maximum around 17–18 ka and could have been sustained by −10 to −8.5 °C temperature depressions relative to modern assuming similar or drier than modern precipitation. Additionally, we present a deglacial chronology from the northern Rocky Mountains that indicates while there is considerable variability in initial moraine abandonment ages across the Rocky Mountains, the pace of subsequent ice retreat through the Lateglacial exhibits some regional coherence. Our results provide insight on potential regional mechanisms driving the initiation of and sustained deglaciation in the western U.S. including rising atmospheric CO 2 and ice sheet collapse. |
format |
Text |
author |
Quirk, Brendon Huss, Elizabeth Laabs, Benjamin Leonard, Eric Licciardi, Joseph Plummer, Mitchell Caffee, Marc |
spellingShingle |
Quirk, Brendon Huss, Elizabeth Laabs, Benjamin Leonard, Eric Licciardi, Joseph Plummer, Mitchell Caffee, Marc Late Pleistocene glacial chronologies and paleoclimate in the northern Rocky Mountains |
author_facet |
Quirk, Brendon Huss, Elizabeth Laabs, Benjamin Leonard, Eric Licciardi, Joseph Plummer, Mitchell Caffee, Marc |
author_sort |
Quirk, Brendon |
title |
Late Pleistocene glacial chronologies and paleoclimate in the northern Rocky Mountains |
title_short |
Late Pleistocene glacial chronologies and paleoclimate in the northern Rocky Mountains |
title_full |
Late Pleistocene glacial chronologies and paleoclimate in the northern Rocky Mountains |
title_fullStr |
Late Pleistocene glacial chronologies and paleoclimate in the northern Rocky Mountains |
title_full_unstemmed |
Late Pleistocene glacial chronologies and paleoclimate in the northern Rocky Mountains |
title_sort |
late pleistocene glacial chronologies and paleoclimate in the northern rocky mountains |
publishDate |
2021 |
url |
https://doi.org/10.5194/cp-2021-106 https://cp.copernicus.org/preprints/cp-2021-106/ |
long_lat |
ENVELOPE(-123.446,-123.446,59.074,59.074) |
geographic |
Northern Rockies |
geographic_facet |
Northern Rockies |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-2021-106 https://cp.copernicus.org/preprints/cp-2021-106/ |
op_doi |
https://doi.org/10.5194/cp-2021-106 |
_version_ |
1766030960531341312 |