Age and impacts of the caldera-forming Aniakchak II eruption in western Alaska

J. J. Blackford, R. J. Payne, M. P. Heggen, A. de la Riva Caballero, J. van der Plicht

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

The mid-Holocene eruption of Aniakchak volcano (Aniakchak II) in southwest Alaska was among the largest eruptions globally in the last 10,000. years (VEI-6). Despite evidence for possible impacts on global climate, the precise age of the eruption is not well-constrained and little is known about regional environmental impacts. A closely spaced sequence of radiocarbon dates at a peatland site over 1000. km from the volcano show that peat accumulation was greatly reduced with a hiatus of approximately 90-120. yr following tephra deposition. During this inferred hiatus no paleoenvironmental data are available but once vegetation returned the flora changed from a Cyperaceae-dominated assemblage to a Poaceae-dominated vegetation cover, suggesting a drier and/or more nutrient-rich ecosystem. Oribatid mites are extremely abundant in the peat at the depth of the ash, and show a longer-term, increasingly wet peat surface across the tephra layer. The radiocarbon sample immediately below the tephra gave a date of 1636-1446. cal yr BC suggesting that the eruption might be younger than previously thought. Our findings suggest that the eruption may have led to a widespread reduction in peatland carbon sequestration and that the impacts on ecosystem functioning were profound and long-lasting.

Original languageEnglish
Pages (from-to)85-95
Number of pages11
JournalQuaternary Research (United States)
Volume82
Early online date17 May 2014
DOIs
Publication statusPublished - Jul 2014

Keywords

  • Acari
  • Beringia
  • Carbon balance
  • Radiocarbon dating
  • Vegetation
  • Volcanic impacts

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Earth-Surface Processes
  • General Earth and Planetary Sciences

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