Monday, 27 August 2007 - 4:40 PM
1.P2.C-4
Neogene tectonic events in the West Antarctic rift system inferred from comparisons with the East African rift and other analogs
Wesley E. Le Masurier, Institute of Arctic and Alpine Research, University of Colorado at Boulder, Boulder, CO 80309-0450
The West Antarctic rift system (WARS) is buried beneath 1-4 km of ice, obscuring vast areas that could provide clues about the potential for active volcanism beneath the ice sheet, and whether significant tectonic extension has taken place in Cenozoic time. This study explores the consequences of viewing the ice as basin fill, and of approximating the mass equivalent of ice as unconsolidated sediment. It then compares the results with active rift systems elsewhere in the world. The results suggest (1) that the interior rift trough is relatively cool and volcanically inactive, (2) that extension and over-deepening of interior basins, has taken place beneath the ice sheet in late Cenozoic time, and (3) that dome uplift and the growth of large central volcanoes along the Marie Byrd Land coast, together with subsidence of interior basins, have significantly increased the relief within the rift system in Neogene time.