HR: 0830h
AN: C31B-0401    [PDF]
TI: New Methods for Enhancing Subglacial Morphology From Airborne Radar Sounding With Implications for Uplift History and Glaciation Between the Transantarctic Mountain Front and the South Pole, Antarctica
AU: * Davis, M B
EM: marcy@utig.ig.utexas.edu
AF: Institute for Geophysics, The John A. and Katherine G. 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@utig.ig.utexas.edu
AF: Institute for Geophysics, The John A. and Katherine G. Jackson School of Geosciences, The University of Texas at Austin, 4412 Spicewood Springs Rd., Bldg. 600, Austin, TX 78759 United States
AB: The Transantarctic Mountains (TAM) form the high boundary between the subsided and extended crust in the Ross Sea Embayment known as the West Antarctic Rift System (WARS) and the East Antarctic craton. The objectives of this study are to characterize the subglacial bedrock morphology of the southern TAM between the Scott and Reedy Glaciers from Ice Stream A to the South Pole along $150\deg$W and to define the geomorphology and structural geology along the southern TAM front through analysis of airborne ice-penetrating radar data. Seismic migration processing methods were applied to approximately 15,000 line km of incoherently detected and differentiated radar sounding records to correct the observed slope of the bed surface and preserve `true' angular relationships for detailed morphological and structural analyses. Subsequently, the ice and bedrock surfaces were picked along each line and combined with the known geology, compiled from various sources, for geomorphologic and structural interpretation. 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 (nw-se) and to WARS rift fabric in the Interior Ross Embayment. Faults oriented obliquely to the TAM break the area of maximum uplift into three nnw-sse trending blocks. Four distinct morphological provinces are identified along the length of the survey based on bed surface elevation analysis. These include: 1) a polar basin and plateau region with low relief features and thick ($\sim$3km) ice cover; 2) an area of alpine glaciation with well-preserved U-shaped valleys that show a glaciation network that flowed opposite (southward) of contemporary glaciers; 3) the TAM massif, the 30-50 km wide region of maximum uplift, includes three 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. This fault zone down - drops the TAM from $>$3000 m to sea level over $\sim$50 km and facilitates the development of valley glaciers and Ice Stream A.
DE: 6994 Instruments and techniques
DE: 8010 Fractures and faults
DE: 8109 Continental tectonics--extensional (0905)
DE: 8110 Continental tectonics--general (0905)
DE: 9310 Antarctica
SC: Cryosphere [C]
MN: 2003 Fall Meeting