HR: 13:55h
AN: C33D-02 [Abstracts]
TI: Subglacial Volcanism in West-Antarctica - A Geologic and Ice Dynamical Perspective
AU: * Vogel, S W
EM: vogel.118@osu.edu
AF: Byrd Polar Research Center, Ohio State University
1090 Carmack Rd
108 Scott Hall, Columbus, OH 43210
United States
AU: * Vogel, S W
EM: vogel.118@osu.edu
AF: Dept. of Earth Sciences, UCSC
1156 High Street, Santa Cruz, Ca 95064
United States
AU: Tulaczyk, S
EM: tulaczyk@es.ucsc.edu
AF: Dept. of Earth Sciences, UCSC
1156 High Street, Santa Cruz, Ca 95064
United States
AU: Carter, S
EM: watercat@mail.utexas.edu
AF: Dept. of Earth Sciences, UCSC
1156 High Street, Santa Cruz, Ca 95064
United States
AU: Renne, P
EM: prenne@bgc.org
AF: Berkeley Geochronology Center, UC-Berkeley
2455 Ridge Road, Berkley, Ca 94709
United States
AU: Turrin, B D
EM: bturrin@rci.rutgers.edu
AF: Dept. of Geological Sciences, Rutgers, The State University of New Jersey
610 Taylor Road, Piscataway, NJ 08854
United States
AU: Turrin, B D
EM: bturrin@rci.rutgers.edu
AF: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964
United States
AU: Joughin, I
EM: Ian Joughin
AB:
Subglacial volcanic eruptions may increase the contribution of the West-Antarctic Ice-Sheet (WAIS) to global sea-level rise
in the near-future by enhancing basal melt water production and ice flow lubrication. Geophysical data have led scientists to
believe that the ice sheet may be located over an extensive, young volcanic province containing ~1 million cubic kilometers
of basalts (Behrendt, 1964; Behrendt et. al., 1991; 1995; 1998). While not all scientists may recognize this theory of
widespread subglacial volcanism, so far no scientific paper has challenged its existence.
Here we present the first geologic constraints on the presence/absence of widespread Late Cenozoic subglacial volcanism
beneath the WAIS and investigate the potential influence of an individual subglacial volcano (Blankenship et. al., 1993) on
the flow dynamic of WAIS. Properties of subglacial sediments indicate limited presence of subglacial volcanic rocks.
Moreover, the only two basaltic pebbles, recovered from the region, are of Mesozoic-Paleozoic age (~100 to ~500 million
years). While these findings reduce the potential for widespread near-future increases in ice discharge from WAIS due to
eruptions of subglacial volcanoes, they do not rule out the presence of individual hot spots associated with volcanic centers
beneath the WAIS. Fuel for the existence of a proposed volcano (Mt. Casertz) on the Whitmore Mountain Ross Sea Transitional
Crust (WRT; Blankenship et. al., 1993), in the southern part of the WAIS, comes from thermo-dynamical modeling in comparison
with observed ice velocities. Ice velocities (Joughin et. al., 1999; 2002) downstream of Mt. Casertz indicate significant
basal sliding, where thermo-dynamical models suggest that the ice sheet is frozen to its base. Routing of basal melt water,
produced in the vicinity of Mt. Casertz, may lubricate the ice base in parts of the WRT, thus enabling basal sliding and
enhancing the discharge of ice in this sector of the WAIS.
The only means to resolve any further questions on the existence of subglacial volcanism in West-Antarctica and its potential
impact on the dynamic of the ice sheet, requires drilling into potential volcanic centers and the recovery of volcanic rocks
for dating and geochemical analysis.
DE: 9310 Antarctica
DE: 8107 Continental neotectonics
DE: 7218 Lithosphere and upper mantle
DE: 1836 Hydrologic budget (1655)
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting