Palaeoproterozoic accretion processes of Australia and comparisons with Laurentia

The Palaeoproterozoic rocks of Australia and Laurentia preserve an excellent record of the accretionary tectonics associated with transitions between the Columbia (Nuna) and Rodinia supercontinents. The geologic records of Australia and Laurentia suggest that the dominant tectonic driver was one or more subduction zones in which several episodes of crustal accretion occurred between ca. 1790 Ma and 1620 Ma. Correlated orogenic events include the ca. 1800-1780 Ma Yapungku-Yambah (Australia)-Medicine Bow (Laurentia) orogenies, ca. 1740-1690 Ma Strangways-Kimban (Australia)-Nimrod (Antarctica)-Yavapai (Laurentia) orogenies, and the ca. 1650-1620 Ma Leibig-Ooldea (Australia)-Mazatzal (Laurentia) orogenies. There are major differences in the style of accretion: Laurentia is characterized by accretion of dominantly juvenile arc terranes, whereas accreted Australian terranes are more evolved and are isotopically similar to the continental nucleus. Adjacent to its plate margin, the Australian continent contained regions of elevated heat production compared with the Laurentian margin. Brace-Goetze lithospheric strength models for ca. 1700 Ma indicate that the Australian plate margin was significantly weaker than that of Laurentia.