Abstract

Paleomagnetic data from East Gondwana (Australia, Antarctica, and India) and Laurentia are interpreted to demonstrate that the two continents were juxtaposed in the Rodinia supercontinent by 1050 Ma. They began to separate after 725 Ma, allowing the formation of the Pacific Ocean. The low-latitude Rapitan and Sturtian glaciations occurred during the rifting that led to continental breakup. East Gondwana remained in low latitudes for the rest of the Neoproterozoic, while Laurentia moved to polar latitudes by 580 Ma. During the Vendian, a wide Pacific Ocean separated the two continental land masses. The younger Marinoan, Ice Brook, and Varangian glaciations in the early Vendian preceded a second continental breakup in the late Vendian, causing formation of the eastern margin of Laurentia and rejuvenation of its western margin. Paleomagnetic data indicate that Gondwana was not fully assembled until the end of the Neoproterozoic, possibly as late as Middle Cambrian.

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