The intraplate Mangaroon Orogeny and its role in the Paleoproterozoic tectonic evolution of the Australian continent

Abstract

The Mangaroon Orogeny (1695–1620 Ma) recorded in the Capricorn Orogen of Western Australia involved magmatism, deformation and metamorphism that are described mostly in the west of the orogen. New geophysical modelling indicates the orogeny also had significant influence in the eastern orogen from the interpreted presence of the magnetic Durlacher Supersuite in the subsurface that is temporally related to the Mangaroon Orogeny. Deposition of specific sedimentary and metasedimentary intervals in the Capricorn Orogen are also indicated to be in close temporal association with the Mangaroon Orogeny as suggested by detrital zircon geochronology. Existing data and new interpretations of provenance information and geophysical datasets have been integrated to propose a different model to previous authors in which the Mangaroon Orogeny involved prominent strike-slip motion, with longer phases of dextral transtension and significant but short-lived phases of sinistral transpression. The switches between sinistral and dextral phases coincide with geodynamic changes in other parts of the Australian proto continent that help explain these alternating kinematic phases. Changing forces from the plate boundary to the east of the Mount Isa-Calvert Superbasin and another to the south, e.g. the Albany-Fraser Orogen, generated variable stress fields. The model implies that the western and eastern Australian Cratons must have been joined by at least the Mangaroon Orogeny, which has an impact on paleo reconstructions of the Australian continent during the late Paleoproterozoic.