Low-altitude periglacial activity in southeastern Australia during the late Pleistocene

Barrows, Timothy T., Mills, Stephanie C., Fitzsimmons, Kathryn, Wasson, Robert, and Galloway, Robert (2022) Low-altitude periglacial activity in southeastern Australia during the late Pleistocene. Quaternary Research. (In Press)

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View at Publisher Website: https://doi.org/10.1017/qua.2021.72
 
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Abstract

Only a small area of the Australian mainland was glaciated during the Pleistocene, whereas periglacial deposits are far more common, indicating that cold environments were extensive and a major influence on landscape evolution. Here we identify representative low-elevation examples of scree slopes and frost action, together with fans and valley fills, indicating pronounced erosion cycles during the Pleistocene. To date the deposits, we explore approaches using radiocarbon, optically stimulated luminescence, and profile dating using the cosmogenic nuclide Be-10. The radiocarbon and optical ages show that screes, alluvial valley fill, and fans were deposited between 66-13 ka during the coldest part of the last glacial cycle, and within the previous glacial cycle. Exposure dating indicates further landscape erosion cycles back to the mid Pleistocene. Together, the deposits indicate the frost cracking limit was similar to 1300 m lower at 680 +/- 10 m and mean winter temperature was 8.2 +/- 0.5 degrees C colder than present. Periglacial conditions probably affected much of southeastern Australia. The treeless and dry conditions resulted in widespread erosion and increased run off. Combined with increased snow storage within catchments, rivers were paradoxically larger, with high seasonal discharge and sediment loads.

Item ID: 72240
Item Type: Article (Research - C1)
ISSN: 0033-5894
Keywords: Pleistocene, Paleoclimatology, Australia, Periglacial geomorphology, Optically stimulated luminescence, Cosmogenic nuclides, Radiocarbon
Copyright Information: Copyright © University of Washington. Published by Cambridge University Press, 2021
Funders: Australian Research Council (ARC)
Projects and Grants: ARC grant DP110103081
Date Deposited: 09 Feb 2022 11:45
FoR Codes: 37 EARTH SCIENCES > 3709 Physical geography and environmental geoscience > 370905 Quaternary environments @ 100%
SEO Codes: 18 ENVIRONMENTAL MANAGEMENT > 1806 Terrestrial systems and management > 180699 Terrestrial systems and management not elsewhere classified @ 100%
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