HR: 11:05h
AN: C12C-04 INVITED     [Abstracts]
TI: Isotopic and Chemical Balance of Large Lakes Beneath the East Antarctic Ice Sheet
AU: * Clarke, G K
EM: clarke@eos.ubc.ca
AF: Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, BC V6T 1Z4 Canada
AU: Bell, R E
EM: robinb@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, P.O. Box 1000, 61 Route 9W, Palisades, NY 10964-8000 United States
AU: Studinger, M
EM: mstuding@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, P.O. Box 1000, 61 Route 9W, Palisades, NY 10964-8000 United States
AB: What we know of large deeply-buried subglacial lakes, such as lakes Vostok and Concordia in East Antarctica, is based on geophysical surveys, satellite remote sensing, ice core drilling, and modeling studies. Together, these data provide information on the geometry, patterns of melting and freezing, and internal processes of the lakes. Slow circulation is driven by lateral variations in water density which are associated with the effects of overburden pressure on the solidus temperature of ice. Evidence for circulation is provided by the pattern of melting and freezing over the ice ceiling and has been confirmed for lakes Vostok and Concordia. The mass, momentum, and energy balance of these lakes have been examined from modeling and observational perspectives but equally fascinating questions concerning the balance of water isotopes and chemical species remain largely unexplored. Applying a steady-state, vertically-integrated model of lake dynamics and thermodynamics, we extend previous work to predict the areal variation of δD, δ¹⁸O, and dissolved impurities. If pronounced spatial variations are present in Lake Vostok these might be expressed as vertical variations in the chemical and isotopic content of accreted ice in the Vostok ice core. The magnitude of such variations would differ from species to species and depend on the ice flow trajectory and patterns of melting and freezing at the lake ceiling.
DE: 0724 Ice cores (4932)
DE: 0726 Ice sheets
DE: 0746 Lakes (9345)
DE: 0776 Glaciology (1621, 1827, 1863)
DE: 0798 Modeling
SC: Cryosphere [C]
MN: Fall Meeting 2005