6bacf37a-662e-4b30-9b26-d9df5c1774d4 urn:uuid eng UTF-8 nonGeographicDataset nonGeographicDataset 2026-04-04T08:32:46 creation ISO 19115 2016 Australia's buoyancy inherited from Gondwanaland 6bacf37a-662e-4b30-9b26-d9df5c1774d4 In company with the other components and continental successors of the Neoproterozoic to Mesozoic Gondwanaland supercontinent, Phanerozoic Australia has a buoyant cratonic platform characterised by non-marine facies, in contrast to the marine facies of the components of depressed Laurasia. As a supercontinent, Gondwanaland lasted much longer than Laurasia, and was therefore hotter from its more effective insulation of internal heat. Moreover, the Pan-African orogenic cycle, confined to Gondwanaland, augmented the heat supply, and I postulate that Pan-African heat generated a permanently buoyant lower crust by mafic underplating. A crustal layer in the Australian Proterozoic shield with subhorizontal reflectors and velocity (Vp) > 7.5 km s-1 is interpreted as the product of mafic underplating beneath latest Neoproterozoic flood basalt. The Pan-African terrane in East Africa also contains evidence of mafic underplating, and most of Gondwanaland (but not Laurasia) was affected by terminal Pan-African (0.5 Ga) uplift and cooling. In equivalent Late Cretaceous and Late Ordovician stages of the 400 m.y. Pangean supercycle, the Australian (and possibly the South American) platform deviated from the global norm by rising faster than eustatic sea level. In Australia, plate boundary events - steeper subduction, mafic underplating of a lower plate along a divergent back-arc boundary - explain uplift in the east, but not that in the west, which relaxed to its natural buoyant state. Earth Sciences GA Publication Journal Published_External Journal article (pdf) documentDigital Journal article (pdf) PDF Unnamed resource documentDigital HTML