HR: 0800h
AN: T11A-1235    [Abstracts]
TI: Subglacial Geology of the Southern Transantarctic Mountains, Antarctica, From Airborne Radar Sounding
AU: * Davis, M B
EM: marcy@ig.utexas.edu
AF: Institute for Geophysics, The Jackson School of Geosciences, The University of Texas at Austin, 4412 Spicewood Springs Rd., Bldg. 600, Austin, TX 78759 United States
AU: Blankenship, D D
EM: blank@ig.utexas.edu
AF: Institute for Geophysics, The Jackson School of Geosciences, The University of Texas at Austin, 4412 Spicewood Springs Rd., Bldg. 600, Austin, TX 78759 United States
AU: Holt, J W
EM: jack@ig.utexas.edu
AF: Institute for Geophysics, The Jackson School of Geosciences, The University of Texas at Austin, 4412 Spicewood Springs Rd., Bldg. 600, Austin, TX 78759 United States
AB: In light of the upcoming International Polar Year (IPY), the value of airborne radar sounding to infer subglacial geology from high resolution geophysical surveys of East Antarctica must be stressed. The potential benefit of such surveys, especially when combined with existing geological data, is demonstrated, in part, by bedrock characterization of the southern Transantarctic Mountains (TAM) between the Scott and Reedy Glaciers and from Ice Stream A to the South Pole along $150\deg$W. Absolute bedrock elevation maps derived from ice sheet surface elevation and thickness reveal four distinct regional subglacial morphologies including 1) a polar basin and plateau region with low relief features and thick (3km) ice cover; 2) an area of well-preserved U-shaped valleys possibly formed by alpine glaciation, 3) the TAM massif, the 30-50 km wide region of maximum uplift that includes subglacial fault blocks and the subaerial part of the TAM; and 4) the TAM front, a normal fault zone that forms the northern terminus of the range by down-dropping the TAM from $>$3000 m to sea level over approximately 50 km. The southern TAM have a southward tilted fault - block structure and are bounded by normal faults on both the north and south sides of the massif. Faults are oriented primarily subparallel to the TAM and to the West Antarctic Rift System fabric in the Interior Ross Embayment. Faults oriented obliquely to the TAM break the area of maximum uplift into three blocks. Ongoing studies of the TAM front focus on discriminating between erosional and faulted topography through more detailed analysis of radar sounding profiles. Adaptation of seismic migration techniques to these data enhances our ability to measure, identify, and map formational contacts and faults indicative of Cenozoic (or older) tectonic processes.
UR: http://www.ig.utexas.edu/research/projects/tam/PPT
DE: 9310 Antarctica
DE: 8010 Fractures and faults
DE: 8040 Remote sensing
DE: 8109 Continental tectonics--extensional (0905)
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting