Mid-Wisconsin to Holocene Permafrost and Landscape Dynamics based on a Drained Lake Basin Core from the Northern Seward Peninsula, Northwest Alaska

Josefine Lenz, Guido Grosse, Benjamin M. Jones, Katey M. Walter Anthony, Anatoly Bobrov, Sabine Wulf, Sebastian Wetterich

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Permafrost-related processes drive regional landscape dynamics in the Arctic terrestrial system. A better understanding of past periods indicative of permafrost degradation and aggradation is important for predicting the future response of Arctic landscapes to climate change. Here, we used a multi-proxy approach to analyse a~4m long sediment core from a drained thermokarst lake basin on the northern Seward Peninsula in western Arctic Alaska (USA). Sedimentological, biogeochemical, geochronological, micropalaeontological (ostracoda, testate amoebae) and tephra analyses were used to determine the long-term environmental Early-Wisconsin to Holocene history preserved in our core for central Beringia. Yedoma accumulation dominated throughout the Early to Late-Wisconsin but was interrupted by wetland formation from 44.5 to 41.5ka BP. The latter was terminated by the deposition of 1m of volcanic tephra, most likely originating from the South Killeak Maar eruption at about 42ka BP. Yedoma deposition continued until 22.5ka BP and was followed by a depositional hiatus in the sediment core between 22.5 and 0.23ka BP. We interpret this hiatus as due to intense thermokarst activity in the areas surrounding the site, which served as a sediment source during the Late-Wisconsin to Holocene climate transition. The lake forming the modern basin on the upland initiated around 0.23ka BP and drained catastrophically in spring 2005. The present study emphasises that Arctic lake systems and periglacial landscapes are highly dynamic and that permafrost formation as well as degradation in central Beringia was controlled by regional to global climate patterns as well as by local disturbances.

Original languageEnglish (US)
Pages (from-to)56-75
Number of pages20
JournalPermafrost and Periglacial Processes
Volume27
Issue number1
DOIs
StatePublished - Jan 1 2016

Bibliographical note

Publisher Copyright:
© 2016 John Wiley & Sons, Ltd.

Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.

Keywords

  • Beringia
  • Bioindicators
  • Cryostratigraphy
  • Palaeoenvironmental reconstruction
  • Tephra
  • Thermokarst lake dynamics
  • Yedoma

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