OCGS Seminar - Sergei Pisarevsky, University of Western Australia

OCGC-Logan Club Invited Speaker Series


Thursday, March 8th, 2012; 1:00PM

Dept. of Earth Sciences, Carleton University

HP 3120


Sergei Pisarevsky

School of Earth and Environment, University of Western Australia

Department of Applied Geology, Curtin University of Technology



How To Reconstruct a Supercontinent



There are various definitions of supercontinents. Some suggest that supercontinent is a landmass comprising more than one continental core, or craton. Others employ the term supercontinent to refer to a single landmass consisting of all the modern continents. In my view both extremes are impractical. Let us call ‘supercontinent’ a landmass comprising a significant part of the existing continental crust. Both Pangea and Gondwana fit this definition. If paleomagnetic data are abundant, the best way for any paleogeographic reconstructions is the matching of Apparent Polar Wander Paths (APWPs) and testing the resulting paleomagnetic reconstruction with geological data. However, there are very few highly reliable Precambrian paleomagnetic data, so the APWP approach does not work here.  Many published Precambrian reconstructions are made either purely paleomagnetically, or without any paleomagnetic data. I try to demonstrate that both extreme approaches are counterproductive. The reconstruction of Precambrian supercontinent should be done by multidisciplinary approach and each step must be carefully documented to make the result testable. There are examples of successful combination of geological and paleomagnetic constraints for the paleogeographic reconstructions. In particular, the synthesis of reconstruction of ancient dyke swarms based on the analysis of Large Igneous Provinces (LIPs) and paleomagnetic studies of LIPs appears to be very productive.