Tuesday, 28 August 2007 - 8:30 AM
2.PL-1

Antarctica and global paleogeography: From Rodinia, through Gondwanaland and Pangea, to the opening of gateways and the birth of the Southern Ocean

Trond H. Torsvik, Carmen Gaina, and Thomas F. Redfield. Center for Geodynamics, Geological Survey of Norway, Leiv Erikssons vei 39, Trondheim, Norway

Most Neoproterozoic Rodinia reconstructions associate East Antarctica (EANT) with Western Australia. By further linking EANT to both Gondwana and Pangea via relative plate circuits a Synthetic Apparent Polar Wander (SAPW) path is calculated. This path predicts that EANT was located at tropical/subtropical southerly latitudes from 1 Ga to 420 Ma. Around 400 Ma and again at 320 Ma, EANT underwent southward drift. Circa 250 Ma Antarctica voyaged briefly north, but headed south again ca. 200 Ma. Since 75 Ma Antarctica became surrounded by spreading centers, and has remained extremely stable.

Although paleomagnetic data of West Antarctic blocks is sparse, we attempt to model their complex kinematics since the Mesozoic. Together with our new EANT SAPW path and circum-Antarctic seafloor spreading history we construct a series of paleogeographic maps from Cambrian to Early Tertiary. Major regional tectonic events are related to SAPW cusps, providing a new view on Austral geotectonics.


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