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Stratigraphy and palaeoenvironments of Richards Island and the eastern Beaufort continental shelf during the last glacial-interglacial cycle

journal contribution
posted on 2023-06-07, 16:46 authored by Julian MurtonJulian Murton
The Pleistocene lithostratigraphy exposed on northern Richards Island comprises seven units that correlate with the offshore seismostratigraphy of the eastern Beaufort Continental Shelf. Land-sea correlations, cryostratigraphic observations and proxy indicators of environmental change provide a record of palaeoenvironmental history that commences before the last glacial-interglacial cycle. After the high sea-level stand of the Last (Sangamonian) Interglaciation, marine regression exposed a large area of the eastern Beaufort Shelf to cold subaerial conditions and permafrost aggradation. Northward progradation of a braided river system was abruptly replaced by aeolian activity, probably as a result of diversion of the palaeo-Porcupine River by the advancing Laurentide Ice Sheet during the Late Wisconsinan. Glaciation of Richards Island by the Mackenzie palaeo-ice stream was brief (sometime between ~22 000 and 16 000 cal. yr BP), and deglaciation had certainly commenced by 14 300 cal. yr BP and perhaps by ~16 000 cal. yr BP or earlier. Major fluvial erosion during the Last Glacial-Interglacial Transition incised cross-shelf valleys and formed a regional erosion surface. The Holocene marine transgression trimmed some of the erosion surface and offshore, covered it with marine deposits.

History

Publication status

  • Published

Journal

Permafrost and Periglacial Processes

ISSN

1045-6740

Publisher

Wiley-Blackwell

Issue

2

Volume

20

Page range

107-125

Pages

19.0

Department affiliated with

  • Geography Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2012-02-06

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