Palaeogeography of the South Australian Craton within Nuna

Integrated geochronology, isotopic and REE geochemical analysis from the northern Gawler Craton were used to test if major boundaries interpreted from geophysical datasets (Baines et al., 2011) truly represent sutures between allochthonous crustal blocks. The northern Gawler Craton appears to be underlain at least in part by Neoarchaean substrate (Reid et al., 2014) that is isotopically similar to basement rocks in southern Gawler Craton and the North Australian Craton. The correlation of Neoarchaean basement in both the southern and northern Gawler Craton (Reid et al., 2014) and lack of systematic isotopic and REE variations suggest that these boundaries separate autochthonous crustal blocks that have been attenuated (and possibly rifted from each other) and re-amalgamated in the Late Palaeoproterozoic to Mesoproterozoic. A modern analogue for this is the SW Pacific in which continental ribbons (e.g. Lord Howe Rise) have been separated from the Australian plate.