Friday, 31 August 2007 - 1:50 PM
5.P1.B-2
Geophysical survey reveals tectonic structures in the Amundsen Sea embayment, West Antarctica
Karsten Gohl1, Dimitry Teterin2, Graeme Eagles1, Gesa Netzeband3, Jan W. G. Grobys1, Nicole Parsiegla1, Philip Schlüter1, Volker Leinweber1, Robert D. Larter4, Gabriele Uenzelmann-Neben1, and Gleb B. Udintsev2. (1) Section of Geophysics, Alfred Wegener Institute for Polar and Marine Research, Am Alten Hafen 26, 27568 Bremerhaven, Germany, (2) Laboratory of Geomorphology and Tectonics of the Ocean Floor, Vernadsky Institute of Geochemistry and Analytical Chemistry, 19 Kosygin St., Moscow, 117975, Russia, (3) Institute for Geophysics, University of Hamburg, Bundesstr. 55, Hamburg, 20146, Germany, (4) British Antarctic Survey, Madingley, High Cross, Cambridge CB3 0ET, United Kingdom
The Amundsen Sea embayment of West Antarctica is in a prominent location for a series of tectonic and magmatic events from Paleozoic to Cenozoic times. Seismic, magnetic and gravity data from the embayment and Pine Island Bay (PIB) reveal the crustal thickness and some tectonic features. The Moho is 24-22 km deep on the shelf. NE-SW trending magnetic and gravity anomalies and the thin crust indicate a former rift zone that was active during or in the run-up to breakup between Chatham Rise and West Antarctica before or at 90 Ma. NW-SE trending gravity and magnetic anomalies, following a prolongation of Peacock Sound, indicate the extensional southern boundary to the Bellingshausen Plate which was active between 79 and 61 Ma.