Origin of last-glacial loess in the western Yukon-Tanana Upland, central Alaska, USA
Abstract Loess is widespread over Alaska, and its accumulation has traditionally been associated with glacial periods. Surprisingly, loess deposits securely dated to the last glacial period are rare in Alaska, and paleowind reconstructions for this time period are limited to inferences from dune ori...
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crcambridgeupr:10.1017/qua.2018.11 2024-06-23T07:45:03+00:00 Origin of last-glacial loess in the western Yukon-Tanana Upland, central Alaska, USA Muhs, Daniel R. Pigati, Jeffrey S. Budahn, James R. Skipp, Gary L. Bettis, E. Arthur Jensen, Britta 2018 http://dx.doi.org/10.1017/qua.2018.11 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S003358941800011X en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Quaternary Research volume 89, issue 3, page 797-819 ISSN 0033-5894 1096-0287 journal-article 2018 crcambridgeupr https://doi.org/10.1017/qua.2018.11 2024-06-05T04:02:09Z Abstract Loess is widespread over Alaska, and its accumulation has traditionally been associated with glacial periods. Surprisingly, loess deposits securely dated to the last glacial period are rare in Alaska, and paleowind reconstructions for this time period are limited to inferences from dune orientations. We report a rare occurrence of loess deposits dating to the last glacial period, ~19 ka to ~12 ka, in the Yukon-Tanana Upland. Loess in this area is very coarse grained (abundant coarse silt), with decreases in particle size moving south of the Yukon River, implying that the drainage basin of this river was the main source. Geochemical data show, however, that the Tanana River valley to the south is also a likely distal source. The occurrence of last-glacial loess with sources to both the south and north is explained by both regional, synoptic-scale winds from the northeast and opposing katabatic winds that could have developed from expanded glaciers in both the Brooks Range to the north and the Alaska Range to the south. Based on a comparison with recent climate modeling for the last glacial period, seasonality of dust transport may also have played a role in bringing about contributions from both northern and southern sources. Article in Journal/Newspaper alaska range Brooks Range glaciers Yukon river Alaska Yukon Cambridge University Press Yukon Quaternary Research 89 3 797 819 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract Loess is widespread over Alaska, and its accumulation has traditionally been associated with glacial periods. Surprisingly, loess deposits securely dated to the last glacial period are rare in Alaska, and paleowind reconstructions for this time period are limited to inferences from dune orientations. We report a rare occurrence of loess deposits dating to the last glacial period, ~19 ka to ~12 ka, in the Yukon-Tanana Upland. Loess in this area is very coarse grained (abundant coarse silt), with decreases in particle size moving south of the Yukon River, implying that the drainage basin of this river was the main source. Geochemical data show, however, that the Tanana River valley to the south is also a likely distal source. The occurrence of last-glacial loess with sources to both the south and north is explained by both regional, synoptic-scale winds from the northeast and opposing katabatic winds that could have developed from expanded glaciers in both the Brooks Range to the north and the Alaska Range to the south. Based on a comparison with recent climate modeling for the last glacial period, seasonality of dust transport may also have played a role in bringing about contributions from both northern and southern sources. |
format |
Article in Journal/Newspaper |
author |
Muhs, Daniel R. Pigati, Jeffrey S. Budahn, James R. Skipp, Gary L. Bettis, E. Arthur Jensen, Britta |
spellingShingle |
Muhs, Daniel R. Pigati, Jeffrey S. Budahn, James R. Skipp, Gary L. Bettis, E. Arthur Jensen, Britta Origin of last-glacial loess in the western Yukon-Tanana Upland, central Alaska, USA |
author_facet |
Muhs, Daniel R. Pigati, Jeffrey S. Budahn, James R. Skipp, Gary L. Bettis, E. Arthur Jensen, Britta |
author_sort |
Muhs, Daniel R. |
title |
Origin of last-glacial loess in the western Yukon-Tanana Upland, central Alaska, USA |
title_short |
Origin of last-glacial loess in the western Yukon-Tanana Upland, central Alaska, USA |
title_full |
Origin of last-glacial loess in the western Yukon-Tanana Upland, central Alaska, USA |
title_fullStr |
Origin of last-glacial loess in the western Yukon-Tanana Upland, central Alaska, USA |
title_full_unstemmed |
Origin of last-glacial loess in the western Yukon-Tanana Upland, central Alaska, USA |
title_sort |
origin of last-glacial loess in the western yukon-tanana upland, central alaska, usa |
publisher |
Cambridge University Press (CUP) |
publishDate |
2018 |
url |
http://dx.doi.org/10.1017/qua.2018.11 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S003358941800011X |
geographic |
Yukon |
geographic_facet |
Yukon |
genre |
alaska range Brooks Range glaciers Yukon river Alaska Yukon |
genre_facet |
alaska range Brooks Range glaciers Yukon river Alaska Yukon |
op_source |
Quaternary Research volume 89, issue 3, page 797-819 ISSN 0033-5894 1096-0287 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/qua.2018.11 |
container_title |
Quaternary Research |
container_volume |
89 |
container_issue |
3 |
container_start_page |
797 |
op_container_end_page |
819 |
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1802650395972993024 |