Tuesday, 28 August 2007
2.PS-49

Plateau collapse model for the Transantarctic Mountains/West Antarctic Rift System: Insights from numerical experiments

Robert W. Bialas1, W. Roger Buck1, Michael Studinger1, and Paul G. Fitzgerald2. (1) Lamont-Doherty Earth Observatory, Columbia University, 61 Rt. 9W, Palisades, NY 10964, (2) Earth Sciences, Syracuse University, 204 Heroy Geology Laboratory, Syracuse, NY 13244

We propose that the West Antarctic Rift System / Transantarctic Mountain region was a high elevation plateau with thicker than normal crust before the onset of continental extension. With major Cretaceous extension, the rift underwent a topographic reversal, and a plateau edge with thickened crust, representing the ancestral Transantarctics, remained. In the Cenozoic minor extension and major denudation reduce the crustal root while simultaneously uplifting peak heights in the mountains. The Cretaceous stage of this concept is investigated using two-dimensional numerical models to determine under what conditions plateau collapse is plausible. Moho temperatures of 675 °C to 850 °C are needed to retain the plateau edge and exhibit wide rifting in the middle of the plateau. We conclude this concept is possible using these numerical experiments, and that application of this idea to the West Antarctic Rift System / Transantarctic Mountain system is also supported by geological and geophysical evidence.

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