Early Holocene Change in Atmospheric Circulation in the Northern Great Plains: An Upstreamview of the 8.2 Ka Cold Event
Elk Lake, in northwestern Minnesota, contains numerous proxy records of climatic and environmental change contained in varved sediments with annual resolution for the last 10,000 years. These proxies show that about 8200 calendar years ago (8.2 cal. ka; 7300 radiocarbon years) Elk Lake went froma we...
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ftunivnebraskali:oai:digitalcommons.unl.edu:usgsstaffpub-1329 2023-11-12T04:18:00+01:00 Early Holocene Change in Atmospheric Circulation in the Northern Great Plains: An Upstreamview of the 8.2 Ka Cold Event Dean, Walter E. Forester, Richard M. Bradbury, J. Platt 2002-01-01T08:00:00Z application/pdf https://digitalcommons.unl.edu/usgsstaffpub/320 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1329/viewcontent/Dean_QSR_2002_Early_Holoene_change.pdf unknown DigitalCommons@University of Nebraska - Lincoln https://digitalcommons.unl.edu/usgsstaffpub/320 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1329/viewcontent/Dean_QSR_2002_Early_Holoene_change.pdf USGS Staff -- Published Research Earth Sciences text 2002 ftunivnebraskali 2023-10-30T10:44:07Z Elk Lake, in northwestern Minnesota, contains numerous proxy records of climatic and environmental change contained in varved sediments with annual resolution for the last 10,000 years. These proxies show that about 8200 calendar years ago (8.2 cal. ka; 7300 radiocarbon years) Elk Lake went froma well-stratified lake that was wind-protected in a boreal forest to a well-mixed lake in open prairie savanna receiving northwesterly wind-blown dust, probably from the dry floor of Lake Agassiz. This change in climate marks the initiation of the widely recognized mid-Holocene “altithermal” in central North America. The coincidence of this change with the so-called 8.2 cal. ka cold event, recognized in ice-core and other records from the circum-North Atlantic, and thought by some to be caused by catastrophic discharge of freshwater from proglacial lakes Agassiz and Ojibway, suggests that the two ‘‘events’’ might be related. Our interpretation of the Elk Lake proxy records, and of other records from less accurately dated sites, suggests that change in climate over North America was the result of a fundamental change in atmospheric circulation in response to marked changes in the relative proportions of land, water, and, especially, glacial ice in North America during the early Holocene. This change in circulation probably post-dates the final drainage of proglacial lakes along the southern margin of the Laurentide ice sheet, and may have produced a minor perturbation in climate over Greenland that resulted in a brief cold pulse detected in ice cores. Text Greenland ice core Ice Sheet North Atlantic University of Nebraska-Lincoln: DigitalCommons@UNL Greenland |
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University of Nebraska-Lincoln: DigitalCommons@UNL |
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ftunivnebraskali |
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Earth Sciences |
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Earth Sciences Dean, Walter E. Forester, Richard M. Bradbury, J. Platt Early Holocene Change in Atmospheric Circulation in the Northern Great Plains: An Upstreamview of the 8.2 Ka Cold Event |
topic_facet |
Earth Sciences |
description |
Elk Lake, in northwestern Minnesota, contains numerous proxy records of climatic and environmental change contained in varved sediments with annual resolution for the last 10,000 years. These proxies show that about 8200 calendar years ago (8.2 cal. ka; 7300 radiocarbon years) Elk Lake went froma well-stratified lake that was wind-protected in a boreal forest to a well-mixed lake in open prairie savanna receiving northwesterly wind-blown dust, probably from the dry floor of Lake Agassiz. This change in climate marks the initiation of the widely recognized mid-Holocene “altithermal” in central North America. The coincidence of this change with the so-called 8.2 cal. ka cold event, recognized in ice-core and other records from the circum-North Atlantic, and thought by some to be caused by catastrophic discharge of freshwater from proglacial lakes Agassiz and Ojibway, suggests that the two ‘‘events’’ might be related. Our interpretation of the Elk Lake proxy records, and of other records from less accurately dated sites, suggests that change in climate over North America was the result of a fundamental change in atmospheric circulation in response to marked changes in the relative proportions of land, water, and, especially, glacial ice in North America during the early Holocene. This change in circulation probably post-dates the final drainage of proglacial lakes along the southern margin of the Laurentide ice sheet, and may have produced a minor perturbation in climate over Greenland that resulted in a brief cold pulse detected in ice cores. |
format |
Text |
author |
Dean, Walter E. Forester, Richard M. Bradbury, J. Platt |
author_facet |
Dean, Walter E. Forester, Richard M. Bradbury, J. Platt |
author_sort |
Dean, Walter E. |
title |
Early Holocene Change in Atmospheric Circulation in the Northern Great Plains: An Upstreamview of the 8.2 Ka Cold Event |
title_short |
Early Holocene Change in Atmospheric Circulation in the Northern Great Plains: An Upstreamview of the 8.2 Ka Cold Event |
title_full |
Early Holocene Change in Atmospheric Circulation in the Northern Great Plains: An Upstreamview of the 8.2 Ka Cold Event |
title_fullStr |
Early Holocene Change in Atmospheric Circulation in the Northern Great Plains: An Upstreamview of the 8.2 Ka Cold Event |
title_full_unstemmed |
Early Holocene Change in Atmospheric Circulation in the Northern Great Plains: An Upstreamview of the 8.2 Ka Cold Event |
title_sort |
early holocene change in atmospheric circulation in the northern great plains: an upstreamview of the 8.2 ka cold event |
publisher |
DigitalCommons@University of Nebraska - Lincoln |
publishDate |
2002 |
url |
https://digitalcommons.unl.edu/usgsstaffpub/320 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1329/viewcontent/Dean_QSR_2002_Early_Holoene_change.pdf |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland ice core Ice Sheet North Atlantic |
genre_facet |
Greenland ice core Ice Sheet North Atlantic |
op_source |
USGS Staff -- Published Research |
op_relation |
https://digitalcommons.unl.edu/usgsstaffpub/320 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1329/viewcontent/Dean_QSR_2002_Early_Holoene_change.pdf |
_version_ |
1782334734152499200 |