HR: 09:00h
AN: C11B-05 INVITED     [Abstracts]
TI: Glacial-geologic and Exposure-dating Constraints on the Antarctic Ice Sheet from Last Glacial Maximum to Present
AU: * Stone, J
EM: stone@geology.washington.edu
AF: Department of Earth and Space Sciences, University of Washington Box 351310, Seattle, WA 98195 United States
AB: The glacial geology of Antarctica is less well known than any other continent, due to inaccessibility and scarcity of outcropping rock. Estimates of the volume of ice stored in the expanded East and West Antarctic Ice Sheets at the LGM are largely based on glacioisostatic modeling and range from 2-37 m equivalent sea level (esl). Geologic studies and exposure dating of deposits in the Ross, Weddell and Amery embayments, and around the East and West Antarctic coasts rule out the extremes of this range, and are broadly compatible with ice-sheet models that predict 10-20 m esl stored in Antarctica during the LGM. At sites studied so far, maximum ice thickness was reached 17-13 kyr BP in East Antarctica, and even later in West Antarctica, delayed thousands of years relative to glacial maximum in the northern hemisphere. Deglaciation records indicate steady recession of both ice sheets, continuing up to the mid-Holocene in East Antarctica and the late Holocene in West Antarctica. There is no evidence from sites studied so far of the large ice volumes and catastrophic deglaciation required to supply meltwater pulses 1A or 1B from Antarctica. Summarised from work with numerous collaborators, and supported by NSF grants OPP-9909776, -9909778, -0230198, and -0229314.
DE: 0726 Ice sheets
DE: 1105 Quaternary geochronology
DE: 1150 Cosmogenic-nuclide exposure dating (4918)
DE: 9310 Antarctica (4207)
SC: Cryosphere [C]
MN: Fall Meeting 2005