Chronostratigraphy of glaciations and permafrost episodes in the Cordillera of western North America
Glaciations in the Cordillera of western North America began during the Late Miocene in the St Elias Range and coastal ranges near Anchorage, Alaska. Radiometric dating of the tephra and lava flows intercalated in the succession of older tills, loesses and outwash deposits permits the reconstruction...
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crsagepubl:10.1177/030913339401800305 2024-10-13T14:07:58+00:00 Chronostratigraphy of glaciations and permafrost episodes in the Cordillera of western North America Harris, Stuart A. 1994 http://dx.doi.org/10.1177/030913339401800305 https://journals.sagepub.com/doi/pdf/10.1177/030913339401800305 en eng SAGE Publications https://journals.sagepub.com/page/policies/text-and-data-mining-license Progress in Physical Geography: Earth and Environment volume 18, issue 3, page 366-395 ISSN 0309-1333 1477-0296 journal-article 1994 crsagepubl https://doi.org/10.1177/030913339401800305 2024-10-01T04:08:21Z Glaciations in the Cordillera of western North America began during the Late Miocene in the St Elias Range and coastal ranges near Anchorage, Alaska. Radiometric dating of the tephra and lava flows intercalated in the succession of older tills, loesses and outwash deposits permits the reconstruction of the probable early glacial sequence along the Cordillera. No one site shows the complete sequence, but the available data suggest synchroneity of the major glacial events throughout the region. The first evidence for cold conditions at low elevations at midlatitudes is from 3.5 Ma BP. By 2.8 Ma, alpine glaciations may have occurred in the Sierra Nevada and ice wedges had formed in bedrock near Fairbanks, Alaska. Three more major glaciations complete with contemporary periglacial and permafrost landforms had occurred by 1.65 Ma, while at least six more major cold events can be recognized during the Quaternary period. Once again, expansion of permafrost conditions occurred during each event and forms an integral part of the evidence for climatic change. Article in Journal/Newspaper Ice permafrost wedge* Alaska SAGE Publications Fairbanks Anchorage Progress in Physical Geography: Earth and Environment 18 3 366 395 |
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SAGE Publications |
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crsagepubl |
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English |
description |
Glaciations in the Cordillera of western North America began during the Late Miocene in the St Elias Range and coastal ranges near Anchorage, Alaska. Radiometric dating of the tephra and lava flows intercalated in the succession of older tills, loesses and outwash deposits permits the reconstruction of the probable early glacial sequence along the Cordillera. No one site shows the complete sequence, but the available data suggest synchroneity of the major glacial events throughout the region. The first evidence for cold conditions at low elevations at midlatitudes is from 3.5 Ma BP. By 2.8 Ma, alpine glaciations may have occurred in the Sierra Nevada and ice wedges had formed in bedrock near Fairbanks, Alaska. Three more major glaciations complete with contemporary periglacial and permafrost landforms had occurred by 1.65 Ma, while at least six more major cold events can be recognized during the Quaternary period. Once again, expansion of permafrost conditions occurred during each event and forms an integral part of the evidence for climatic change. |
format |
Article in Journal/Newspaper |
author |
Harris, Stuart A. |
spellingShingle |
Harris, Stuart A. Chronostratigraphy of glaciations and permafrost episodes in the Cordillera of western North America |
author_facet |
Harris, Stuart A. |
author_sort |
Harris, Stuart A. |
title |
Chronostratigraphy of glaciations and permafrost episodes in the Cordillera of western North America |
title_short |
Chronostratigraphy of glaciations and permafrost episodes in the Cordillera of western North America |
title_full |
Chronostratigraphy of glaciations and permafrost episodes in the Cordillera of western North America |
title_fullStr |
Chronostratigraphy of glaciations and permafrost episodes in the Cordillera of western North America |
title_full_unstemmed |
Chronostratigraphy of glaciations and permafrost episodes in the Cordillera of western North America |
title_sort |
chronostratigraphy of glaciations and permafrost episodes in the cordillera of western north america |
publisher |
SAGE Publications |
publishDate |
1994 |
url |
http://dx.doi.org/10.1177/030913339401800305 https://journals.sagepub.com/doi/pdf/10.1177/030913339401800305 |
geographic |
Fairbanks Anchorage |
geographic_facet |
Fairbanks Anchorage |
genre |
Ice permafrost wedge* Alaska |
genre_facet |
Ice permafrost wedge* Alaska |
op_source |
Progress in Physical Geography: Earth and Environment volume 18, issue 3, page 366-395 ISSN 0309-1333 1477-0296 |
op_rights |
https://journals.sagepub.com/page/policies/text-and-data-mining-license |
op_doi |
https://doi.org/10.1177/030913339401800305 |
container_title |
Progress in Physical Geography: Earth and Environment |
container_volume |
18 |
container_issue |
3 |
container_start_page |
366 |
op_container_end_page |
395 |
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1812814548762099712 |