THE AGE OF NEOPROTEROZOIC-PALAEOZOIC SEDIMENTS WITHIN THE OFFICER BASIN OF THE CENTRALIAN SUPER-BASIN CAN BE CONSTRAINED BY MAJOR SEQUENCE-BOUNDING UNCONFORMITIES

Abstract

The age of stratigraphic units within the Neoproterozoic of the Centralian Super-Basin caii be constrained by using major sequence bounding unconformities. The Officer Basin is redefined to include the Yeneena, Karara, and Savory Basins.

Correlation of structural and stratigraphic relationships apparent in surface geological maps to seismic and borehole data leads to the conclusion that the Petermann Ranges Orogeny and the Paterson Orogeny are the same event. The name Petermann Ranges Orogeny has been used extensively in the Centralian Super-basin. It is considered for this publication, to be correlated with and hence to replace the term 'Paterson Orogeny'. This Tectonic event occurred at 540 to 570 Ma and postdated deposition of the Boondawari, Lupton, Pertatataka and Julie Formations and Rodda Beds. These Formations are correlated as part of the same depositional episode; which is separated from the younger Babbagoola Formation and lateral equivalents by a regional unconformity resulting from the Petermann Ranges Orogeny. The Babbagoola Formation is correlated with the Tchukardine and McFadden Formations of the Savory Sub-basin and the Relief Sandstone of the eastern Officer Basin.

The Petermann Ranges Orogeny produced a central uplift which includes the Rudall and Musgrave Complexes, forming the north-eastern boundary of the Officer Basin. The Musgrave Complex advanced further south in comparison to the Rudall Complex, with accommodation along numerous north and northeast trending faults. Initial movement along these faults probably started as early as Cambrian and was repeatedly reactivated till post Miocene.

Extensive reverse faulting, folding and initiation of diapiric movement of the Upper Proterozoic section began in late Neoproterozoic to Early Cambrian. Reactivation of diapiric movement and folding occurred after and before extrusion of the Table Hill Volcanics. Salt movement continued during the post-Permian and post-Early Cretaceous periods. The evolution of salt structures in the basin from Neoproterozoic to post-Cretaceous provides many different aged traps for migrating hydrocarbons.