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Volcanic Ash Record in the Siple Dome Ice Core

Volcanic Ash Record in the Siple Dome Ice Core N.W. Dunbar 1 , A. Kurbatov 2 , G.A. Zielinski 2 , W.C. McIntosh 1 , P.B. Price 3 , R.C. Bay 3 1. E&ES Department, New Mexico Tech, Socorro, NM, 87801 2. Climate Change Institute, University of Maine, Orono, ME 04469-5790

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Volcanic Ash Record in the Siple Dome Ice Core

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  1. Volcanic Ash Record in the Siple Dome Ice Core N.W. Dunbar1, A. Kurbatov2, G.A. Zielinski2, W.C. McIntosh1, P.B. Price3, R.C. Bay3 1. E&ES Department, New Mexico Tech, Socorro, NM, 87801 2. Climate Change Institute, University of Maine, Orono, ME 04469-5790 3. Physics Department, University of California, Berkeley, CA 94720

  2. Techniques for finding tephra layers in ice cores • Visual identification • Sulfate record • Searching at depth of known eruptions • Optical dust logger

  3. Tephra layers found in Siple Dome A ice core A total of 40 layers with adequate ash for chemical analysis have been found.

  4. Analysis of tephra layers in the Siple Dome core indicates derivation from: Mt. Berlin (most layers) Mt. Takahe Pleiades Volcanic Center/Mt. Melbourne local basaltic centers in the Royal Society Range at least one non-Antarctic volcano

  5. Microbeam chemical analysis of glass shards in tephra layers coupled with statistical difference calculations allows: 1. Correlation to tephra layers in other ice cores 2. Correlation to eruptions of known age to provide time-stratigraphic markers

  6. Cross-correlation between ice cores 79.2 m 1147 yrs bef. 1995?? Prefer 675+/-25 yrs before 1996 97.2-97.7 m 703 yrs before 1995

  7. Mt. Hudson 11.1+/-1.8 Mt. Berlin 10.3+/-2.7 Mt. Takahe 8.2+/-2.7

  8. TIf Mt. Hudson 11.1+/-1.8 Mt. Berlin 10.3+/-2.7 Mt. Takahe 8.2+/-2.7

  9. Mt. Berlin <118.7+/-2.5?? Mt. Berlin <92.2+/-0.9 Mt. Berlin 24.7+/-1.5 Mt. Berlin 18.2+/-5.8

  10. Conclusions • There are many identifiable and analyzable tephra layers in the Siple Dome Ice Core, and probably will be in other WAIS cores • Most tephra layers are locally-derived, most having been erupted from Mt. Berlin, located in West Antarctica, although Mt. Takahe, the Pleiades volcano and some basaltic centers are also represented. • Several non-local tephra (probably South American) have also been identified • Cross correlation of tephra layers between ice cores allow for better-dated cores to aid in dating of other cores. This also provide absolute time-stratigraphic markers between cores • Chronology of tephra layers in the upper part of the Siple Dome core agree well with existing chronology, however agreement in the lower part of the core is less good. • Further dating of source ashes (Mt. Berlin) may provide further information about age of lower Siple Dome tephra layers

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