Origin of last-glacial loess in the western Yukon-Tanana Upland, central Alaska, USA
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...
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ftunivnebraskali:oai:digitalcommons.unl.edu:usgsstaffpub-2103 2023-11-12T04:00:01+01:00 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, III Jensen, Britta 2018-01-23T08:00:00Z application/pdf https://digitalcommons.unl.edu/usgsstaffpub/1101 https://digitalcommons.unl.edu/context/usgsstaffpub/article/2103/viewcontent/Muhs_QR_2018_Origin_of_last_glacial_loess.pdf unknown DigitalCommons@University of Nebraska - Lincoln https://digitalcommons.unl.edu/usgsstaffpub/1101 https://digitalcommons.unl.edu/context/usgsstaffpub/article/2103/viewcontent/Muhs_QR_2018_Origin_of_last_glacial_loess.pdf USGS Staff -- Published Research Loess Alaska Last glacial period Mineralogy Geochemistry Provenance Paleowinds Earth Sciences Geology Oceanography and Atmospheric Sciences and Meteorology Other Earth Sciences Other Environmental Sciences text 2018 ftunivnebraskali 2023-10-30T11:50:31Z 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. Text alaska range Brooks Range glaciers Yukon river Alaska Yukon University of Nebraska-Lincoln: DigitalCommons@UNL Yukon |
institution |
Open Polar |
collection |
University of Nebraska-Lincoln: DigitalCommons@UNL |
op_collection_id |
ftunivnebraskali |
language |
unknown |
topic |
Loess Alaska Last glacial period Mineralogy Geochemistry Provenance Paleowinds Earth Sciences Geology Oceanography and Atmospheric Sciences and Meteorology Other Earth Sciences Other Environmental Sciences |
spellingShingle |
Loess Alaska Last glacial period Mineralogy Geochemistry Provenance Paleowinds Earth Sciences Geology Oceanography and Atmospheric Sciences and Meteorology Other Earth Sciences Other Environmental Sciences Muhs, Daniel R Pigati, Jeffrey S. Budahn, James R. Skipp, Gary L. Bettis, E Arthur, III Jensen, Britta Origin of last-glacial loess in the western Yukon-Tanana Upland, central Alaska, USA |
topic_facet |
Loess Alaska Last glacial period Mineralogy Geochemistry Provenance Paleowinds Earth Sciences Geology Oceanography and Atmospheric Sciences and Meteorology Other Earth Sciences Other Environmental Sciences |
description |
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 |
Text |
author |
Muhs, Daniel R Pigati, Jeffrey S. Budahn, James R. Skipp, Gary L. Bettis, E Arthur, III Jensen, Britta |
author_facet |
Muhs, Daniel R Pigati, Jeffrey S. Budahn, James R. Skipp, Gary L. Bettis, E Arthur, III 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 |
DigitalCommons@University of Nebraska - Lincoln |
publishDate |
2018 |
url |
https://digitalcommons.unl.edu/usgsstaffpub/1101 https://digitalcommons.unl.edu/context/usgsstaffpub/article/2103/viewcontent/Muhs_QR_2018_Origin_of_last_glacial_loess.pdf |
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 |
USGS Staff -- Published Research |
op_relation |
https://digitalcommons.unl.edu/usgsstaffpub/1101 https://digitalcommons.unl.edu/context/usgsstaffpub/article/2103/viewcontent/Muhs_QR_2018_Origin_of_last_glacial_loess.pdf |
_version_ |
1782341595034550272 |