Friday, 31 August 2007 - 11:00 AM

Integrated tephrochronology of the West Antarctic region- implications for a potential tephra record in the West Antarctic Ice Sheet (WAIS) Divide Ice Core

Nelia W. Dunbar1, William C. McIntosh1, Andrei V. Kurbatov2, and Thomas I. Wilch3. (1) NMBG/Earth and Environmental Sciences Department, New Mexico Tech, 801 Leroy Pl, Socorro, NM 87801, (2) Climate Change Institute, University of Maine, 303 Bryand Global Sciences Center, Orono, ME 04469, (3) Department of Geological Sciences, Albion College, 611 East Porter St., Albion, MI 49224

Mount Berlin and Mt. Takahe, two polygenetic volcanoes in West Antarctica have produced a number of explosive, ashfall generating eruptions over the past 500,000 yrs.  These eruptions dispersed volcanic ash over large areas of the West Antarctic Ice Sheet.  Evidence of these eruptions is observed at two blue ice sites (Mt. Waesche and Mt. Moulton) as well as in the Siple Dome and Byrd (Palais et al., 1988) ice cores.  Geochemical correlations between tephra sampled at the source volcanoes, at blue ice sites, and in the Siple Dome ice core suggest that at least some of the eruptions covered large areas of the ice sheet with volcanic ash, and 40Ar/39Ar dating of volcanic material provides precise timing when these events occurred.   Volcanic ash from some of these events is expected to be found in the WAIS Divide ice core, providing chronology and inter-site correlation.