HR: 1330h
AN: V52A-1056
TI: Holocene Volcanic Records in the Siple Dome Ice Cores
AU: Zielinski, G A
AF: Institute for Quaternary and Climate Studies, University of Maine, 303 Bryand GSC, University of Maine , Orono, ME 04469 United States
AU: Dunbar, N W
AF: N.M.B.M.M.R./E&ES Department, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801 United States
AU: * Kurbatov, A V
AF: Institute for Quaternary and Climate Studies, University of Maine, 303 Bryand GSC, University of Maine , Orono, ME 04469 United States
AU: Voisin, D T
AF: Climate Change Research Center, University of New Hampshire, 39 College Road, Durham, NH 03824 United States

AB: Using both the SO$_{4}$$^{2-}$ and Cl$^{-}$ time series and tephrochronological analyses, a highly detailed record of Holocene volcanism is being reconstructed from the Siple Dome A ice core. The volcanic glaciochemical record is being developed at a 2-4 year resolution for the last 10,000 years. Volcanic peaks were identified as those having a concentration of 2${\sigma}$ above the mean positive residual of the spline fit, as was done for the GISP2 volcanic record. We identified about 70 volcanic events for the mid-late Holocene. The largest sulfate signal (350 ppb) over the time period evaluated occurs at 2242 years ago. Large signals of volcanically enhanced sulfate in the ice core record also occur around 720 years ago (1280 C.E.;194-249 ppb)and 4710 years ago (378ppb). Ages for large equatorial or southern hemisphere volcanic eruptions are synchronous with identified sulfate peaks in the reconstructed volcanic record. However, the continuous scan for volcanic glass in these same samples yielded glass compositions more in-line with Antarctica volcanic zones (i.e., local eruptions). Nevertheless, our record provides important information on the atmospheric impact of volcanism in Antarctica geochemical cycles. The glass (i.e., tephra) found in various samples indicate that volcanoes within the McMurdo Volcanic Center (Victoria Land and the islands off its coast) including Mt. Melbourne, The Pleaides and Buckle Island appear to be the most active in Antarctica during the late Holocene. Rhyolitic shards of a composition not found in Antarctica also are present in some layers, although they are not overly abundant. The presence of dust with a Patagonian origin in East Antarctica ice cores as well as the nature of the Antarctica vortex indicate that material from this part of the southern hemisphere can reach various parts of Antarctica. Common circulation patterns around the Ross and Amundson Seas as well as the satellite trace of aerosols from the 1991 Cerro Hudson eruption, Argentina, provide a possible transport route for glass to reach the Siple Dome site. Our tephra work is providing a new chronology of Antarctica volcanism.

DE: 0305 Aerosols and particles (0345, 4801)
DE: 0370 Volcanic effects (8409)
MN: 2001 AGU Fall Meeting