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

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

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. © 2014 University of Washington.

Citation

Blackford, J., Payne, R., Heggen, M., de la Riva Caballero, A., & van der Plicht, J. (2014). Age and impacts of the caldera-forming Aniakchak II eruption in western Alaska. Quaternary Research, 82(1), 85-95. https://doi.org/10.1016/j.yqres.2014.04.013

• Journal Article Type: Article
• Acceptance Date: Aug 1, 2014
• Online Publication Date: Jan 20, 2017
• Publication Date: 2014-07
• Deposit Date: Aug 6, 2018
• Journal: Quaternary Research (United States)
• Print ISSN: 0033-5894
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 82
• Issue: 1
• Pages: 85-95
• DOI: https://doi.org/10.1016/j.yqres.2014.04.013
• Keywords: Volcanic impacts; Vegetation; Carbon balance; Beringia; Acari; Radiocarbon dating
• Public URL: https://hull-repository.worktribe.com/output/524411
• Publisher URL: https://www.cambridge.org/core/journals/quaternary-research/article/age-and-impacts-of-the-calderaforming-aniakchak-ii-eruption-in-western-alaska/CC8AB90ED8D1DB9FFE960041B9BCAD35