HR: 0800h
AN: T11A-1226    [Abstracts]
TI: Upper Mantle Structure Beneath the Transantarctic Mountains From Body-Wave Tomography and Receiver Functions Using TAMSEIS Data
AU: * Watson, T
EM: tdw130@psu.edu
AF: Penn State University, Department of Geosciences, 503 Deike Building, University Park, PA 16802 United States
AU: Larson, A M
EM: alarson@geosc.psu.edu
AF: Penn State University, Department of Geosciences, 503 Deike Building, University Park, PA 16802 United States
AU: Nyblade, A
EM: andy@geosc.psu.edu
AF: Penn State University, Department of Geosciences, 503 Deike Building, University Park, PA 16802 United States
AU: Benoit, M
EM: mbenoit@geosc.psu.edu
AF: Penn State University, Department of Geosciences, 503 Deike Building, University Park, PA 16802 United States
AU: Wiens, D A
EM: doug@seismo.wustl.edu
AF: Washington University, Department of Earth and Planetary Sciences, 1 Brookings Drive, St. Louis, MO 63130-4899 United States
AU: Anandakrishnan, S
EM: sak@geosc.psu.edu
AF: Penn State University, Department of Geosciences, 503 Deike Building, University Park, PA 16802 United States
AU: Shore, P
EM: patrick@seismo.wustl.edu
AF: Washington University, Department of Earth and Planetary Sciences, 1 Brookings Drive, St. Louis, MO 63130-4899 United States
AU: Voigt, D
EM: voigt@geosc.psu.edu
AF: Penn State University, Department of Geosciences, 503 Deike Building, University Park, PA 16802 United States
AB: The Transantarctic Mountains (TAM) consists of gently tilted fault blocks resulting from vertical crustal movement during the Cenozoic. Paralleling much of the West Antarctic Rift System, the TAM is considered by many to be a classic example of rift flank uplift, however evidence supporting a clear uplift mechanism has yet to be provided. Additionally, the adjacent East Antarctic Craton exhibits anomalously high elevation for a cratonic block, approximately 1 km above sea level, when corrected for glacial loading. To investigate these two unique tectonic features of the Antarctic continent, body-wave tomography and receiver-function stacking are being conducted with broadband seismic data collected by the 2000-2003 Transantarctic Seismic Experiment (TAMSEIS). With these analyses, we can make inferences about the thermal structure of the upper mantle beneath portions of the TAM and East Antarctic Craton. Constraints on the thermal state of the upper mantle beneath these regions may enable us to discriminate between the competing uplift models. The multi-channel cross-correlation method of VanDecar and Crosson (1991) has been used to accurately determine relative P and S wave arrival times and uncertainty estimates for teleseismic events. Travel-time residuals indicate azimuthal variability and that slower velocities are present beneath the Transantarctic Mountains than the East Antarctic Craton. The travel time residuals will be inverted for upper mantle structure. Receiver functions for several hundred teleseismic earthquakes have been computed and are being stacked to image the 410 and 660 km discontinuities. Topography on the discontinuities will be correlated with seismic velocity anomalies to help constrain the depth extent of thermal anomalies in the upper mantle.
DE: 8180 Tomography
DE: 9310 Antarctica
DE: 8120 Dynamics of lithosphere and mantle--general
DE: 7200 SEISMOLOGY
DE: 7203 Body wave propagation
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting