Timing the breakup of a Proterozoic supercontinent: Evidence from Australian intracratonic basins

In the Late Proterozoic, several broad, shallow, intracratonic depressions appeared across a vast area of central Australia. The basins, which all contain shallow marine to fluvial successions, appear to have been tenuously interconnected through much of their history. Analysis of their fill by means of tectonic-subsidence curves suggests that they are the product of two separate and distinct periods of crustal extension, one at about 900 Ma and a second at about 600 Ma. These extensional episodes were probably the result of failed rifting events that almost fragmented the Australian continent during the Late Proterozoic. The second period of extension almost certainly relates to the breakup of a Proterozoic supercontinent. The results suggest that sediments preserved in the relatively protected environment of interior basins may provide a more subtle record of major tectonic events than continental margin sequences that were exposed to major continental interactions.