Comparing 1800-1600 Ma accretionary and basin processes in Australia and Laurentia: Possible geographic connections in Columbia

Abstract

We focus on potential pinning points on the southern and eastern margins of Australia and the southern and western margins of Laurentia and interpret a convergent plate boundary along the southern margin of the proto-Australian continent during the Palaeo- to Mesoproterozoic (1800-1600 Ma). Specific geological events within the southern Australian margin can be correlated with events preserved along the Medicine Bow-Yavapai-Mazatzal Belt in southwestern Laurentia. These belts were characterised by southward continental growth with varying degrees of crustal reworking and accretion of juvenile material. In Australia crustal reworking appears to have been the dominant process from 1800 to 1670 Ma, with more juvenile material accreted at 1620 Ma. In contrast, the Southern Laurentian terranes were dominated by accretion of juvenile material from 1800 to 1620 Ma, although reworked continental crust was also accreted to the margin. In the interior of both continents basins developed with comparable histories from 1800 to 1670 Ma. Thereafter the evolution of the interior basins diverged, with sag-phase processes dominant in Northern Australia and a protracted depositional hiatus in Laurentia. The geologic evolution is consistent with palaeomagnetic data and provides further evidence for geographic links between Eastern Australia and Western Laurentia from 1800 to 1600 Ma. © 2008 Elsevier B.V. All rights reserved.