The geochemistry of loess: Asian and North American deposits compared
Loess is widely distributed over Asia and North America and constitutes one of the most important surficial deposits that serve as terrestrial records of the Quaternary. The oldest Pleistocene loess in China is likely ∼2.6 Ma, thus spanning much or all of the Pleistocene. In North America, most loes...
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ftunivnebraskali:oai:digitalcommons.unl.edu:usgsstaffpub-2099 2023-11-12T04:28:01+01:00 The geochemistry of loess: Asian and North American deposits compared Muhs, Daniel R 2017-10-27T07:00:00Z application/pdf https://digitalcommons.unl.edu/usgsstaffpub/1091 https://digitalcommons.unl.edu/context/usgsstaffpub/article/2099/viewcontent/Muhs_JAES_2018_The_geochemistry_of_loess.pdf unknown DigitalCommons@University of Nebraska - Lincoln https://digitalcommons.unl.edu/usgsstaffpub/1091 https://digitalcommons.unl.edu/context/usgsstaffpub/article/2099/viewcontent/Muhs_JAES_2018_The_geochemistry_of_loess.pdf USGS Staff -- Published Research Asia North America Loess Geochemistry Major elements Trace elements Provenance Paleosols Chemical weathering Paleoclimates Earth Sciences Geology Oceanography and Atmospheric Sciences and Meteorology Other Earth Sciences Other Environmental Sciences text 2017 ftunivnebraskali 2023-10-30T11:50:23Z Loess is widely distributed over Asia and North America and constitutes one of the most important surficial deposits that serve as terrestrial records of the Quaternary. The oldest Pleistocene loess in China is likely ∼2.6 Ma, thus spanning much or all of the Pleistocene. In North America, most loess is no older than the penultimate glacial period, with the exception of Alaska, where the record may go back to ∼3.0 Ma. On both continents, loess deposits date primarily to glacial periods, and interglacial or interstadial periods are represented by paleosols. Both glacial and non-glacial sources of silts that comprise the bulk of loess deposits are found on both continents. Although loess has been considered to be representative of the average upper continental crust, there are regionally distinctive compositions of loess in both Asia and North America. Loess deposits in Asia from Yakutia, Tajikistan, and China have compositionally distinct major element compositions, due to varying abundances of silicate minerals, carbonate minerals, and clay minerals. In North America, loess in the Mississippi River valley, the Great Plains, and Alaska are also distinguishable with regard to major element composition that reflects highly diverse source sediments. Trace element geochemistry (Sc-Th-Zr and the rare earth elements) also shows regional diversity of loess bodies, in both Asia and North America. On both continents, most loess bodies show significant contributions from later-cycle, altered sedimentary rocks, as opposed to direct derivation from igneous rocks. Further, some loess bodies have detectable contributions from mafic igneous rocks as well as major contributions from average, upper-crustal, felsic rocks. Intercalated paleosols in loess sections show geochemical compositions that differ significantly from the underlying loess parent materials. Ratios of soluble-to-insoluble elements show depletions in paleosols due to chemical weathering losses of calcite, dolomite, plagioclase, mica, apatite, and smectite. In ... Text Yakutia Alaska University of Nebraska-Lincoln: DigitalCommons@UNL |
institution |
Open Polar |
collection |
University of Nebraska-Lincoln: DigitalCommons@UNL |
op_collection_id |
ftunivnebraskali |
language |
unknown |
topic |
Asia North America Loess Geochemistry Major elements Trace elements Provenance Paleosols Chemical weathering Paleoclimates Earth Sciences Geology Oceanography and Atmospheric Sciences and Meteorology Other Earth Sciences Other Environmental Sciences |
spellingShingle |
Asia North America Loess Geochemistry Major elements Trace elements Provenance Paleosols Chemical weathering Paleoclimates Earth Sciences Geology Oceanography and Atmospheric Sciences and Meteorology Other Earth Sciences Other Environmental Sciences Muhs, Daniel R The geochemistry of loess: Asian and North American deposits compared |
topic_facet |
Asia North America Loess Geochemistry Major elements Trace elements Provenance Paleosols Chemical weathering Paleoclimates Earth Sciences Geology Oceanography and Atmospheric Sciences and Meteorology Other Earth Sciences Other Environmental Sciences |
description |
Loess is widely distributed over Asia and North America and constitutes one of the most important surficial deposits that serve as terrestrial records of the Quaternary. The oldest Pleistocene loess in China is likely ∼2.6 Ma, thus spanning much or all of the Pleistocene. In North America, most loess is no older than the penultimate glacial period, with the exception of Alaska, where the record may go back to ∼3.0 Ma. On both continents, loess deposits date primarily to glacial periods, and interglacial or interstadial periods are represented by paleosols. Both glacial and non-glacial sources of silts that comprise the bulk of loess deposits are found on both continents. Although loess has been considered to be representative of the average upper continental crust, there are regionally distinctive compositions of loess in both Asia and North America. Loess deposits in Asia from Yakutia, Tajikistan, and China have compositionally distinct major element compositions, due to varying abundances of silicate minerals, carbonate minerals, and clay minerals. In North America, loess in the Mississippi River valley, the Great Plains, and Alaska are also distinguishable with regard to major element composition that reflects highly diverse source sediments. Trace element geochemistry (Sc-Th-Zr and the rare earth elements) also shows regional diversity of loess bodies, in both Asia and North America. On both continents, most loess bodies show significant contributions from later-cycle, altered sedimentary rocks, as opposed to direct derivation from igneous rocks. Further, some loess bodies have detectable contributions from mafic igneous rocks as well as major contributions from average, upper-crustal, felsic rocks. Intercalated paleosols in loess sections show geochemical compositions that differ significantly from the underlying loess parent materials. Ratios of soluble-to-insoluble elements show depletions in paleosols due to chemical weathering losses of calcite, dolomite, plagioclase, mica, apatite, and smectite. In ... |
format |
Text |
author |
Muhs, Daniel R |
author_facet |
Muhs, Daniel R |
author_sort |
Muhs, Daniel R |
title |
The geochemistry of loess: Asian and North American deposits compared |
title_short |
The geochemistry of loess: Asian and North American deposits compared |
title_full |
The geochemistry of loess: Asian and North American deposits compared |
title_fullStr |
The geochemistry of loess: Asian and North American deposits compared |
title_full_unstemmed |
The geochemistry of loess: Asian and North American deposits compared |
title_sort |
geochemistry of loess: asian and north american deposits compared |
publisher |
DigitalCommons@University of Nebraska - Lincoln |
publishDate |
2017 |
url |
https://digitalcommons.unl.edu/usgsstaffpub/1091 https://digitalcommons.unl.edu/context/usgsstaffpub/article/2099/viewcontent/Muhs_JAES_2018_The_geochemistry_of_loess.pdf |
genre |
Yakutia Alaska |
genre_facet |
Yakutia Alaska |
op_source |
USGS Staff -- Published Research |
op_relation |
https://digitalcommons.unl.edu/usgsstaffpub/1091 https://digitalcommons.unl.edu/context/usgsstaffpub/article/2099/viewcontent/Muhs_JAES_2018_The_geochemistry_of_loess.pdf |
_version_ |
1782341391094906880 |