Evidence of the 2011 Puyehue-Córdon Caulle Eruption in West Antarctica
Abstract
Gases and aerosols emitted during volcanic eruptions can have widespread impacts, including global climate cooling, disruption to air travel, and a reduction in air quality. Ice core records offer highly temporally resolved archives of past volcanic eruptions, allowing for precise tephrostratigraphy as well as estimates of past volcanic impacts on Earth's radiative balance. Previous work in West Antarctica has shown that the latitude and/or magnitude of past eruptions can be inferred on the basis of changes in particle size distributions (PSDs) relative to background dust, as well as phasing between ash particle and sulfate aerosol deposition. Specifically, explosive tropical eruptions show finer-than-background PSDs and clear phasing between (earlier) ash and (later) sulfate deposition, while high-latitude eruptions exhibit coarser-than-background PSDs. In order to assess the depositional characteristics of a mid-latitude eruption for comparison with these earlier observations, we evaluated the June 4-6, 2011 VEI 5 eruption of Puyehue-Córdon Caulle, Chile (40.59°S). Satellite imagery shows the ash cloud from the eruption passing directly over central West Antarctica, suggesting that ash particle deposition may have occurred. We collected surface snow samples from the West Antarctic Ice Sheet (WAIS) Divide field camp in January 2012 and analyzed them for major ion concentrations and particle concentration and size distribution using ion chromatographs and a Coulter-Counter, respectively. The annually resolved snowpit record, which extends to June 2009, does not have elevated sulfate concentrations linked with the Puyehue eruption. However, particle analyses indicate that ash deposition did occur, with ash particles coarser than background dust (>12 μm diameter vs. modal diameter of 5 μm). The coarseness of ash particles, similar to those from high-latitude eruptions, is consistent with tropospheric transport. On the basis of these results, we suggest that mid-latitude eruptions can be distinguished from explosive tropical eruptions in the WAIS Divide ice core, similar to previous results distinguishing tropical from high-latitude eruptions. Further, the observed ash layer may serve as a new chronostratigraphic marker for West Antarctica.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.V11A2759D
- Keywords:
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- 8455 Tephrochronology;
- VOLCANOLOGY