Towards a Tectonic Geography of Neoproterozoic Australian Gondwana

Abstract

Australian Gondwana formed by the Ediacaran collision of Neoproterozoic Australia (consisting of cratonic Australia and its continuation into East Antarctica) with Neoproterozoic India (also consisting of the Indian subcontinent with a large extension into East Antarctica), the Congo-Tanzania-Bangweulu Block of central Africa and Azania (a Neoproterozoic continent consisting of southern peninsular India, central Madagascar and parts of East Africa and southern Arabia). Outline palaeogeographies of the interactions between these continents can be constructed by looking at the available high-quality palaeomagnetic solutions for these continents. However, these are sparse for the continents in question in the Neoproterozoic. Interrogating the timing and nature of orogenesis in the collision zones between these continents (the East African Orogen and the Kuunga Orogen) provides more precision when integrated with the palaeomagnetic data. However, these only really provide palaeogeographic information for the final stages of the formation of Gondwana. A third major paradigm is to investigate the ocean plate tectonic history. This is only possible by investigating the timing and nature of the remnant volcanic arc rocks now preserved metamorphosed and deformed in the orogens—and by looking at the detrital products of these arcs. Here we present the first steps to an oceanic-plate integrated tectonic geography of the Neoproterozoic of what was to become central and eastern Gondwana. This is the first time that a tectonic geography has attempted to integrate the evolution of oceanic-plate margins with continental interactions to better constrain whole plate evolutions in the Proterozoic—at a time when the first voluminous, productive source rocks were being depositied.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015