STRUCTURAL EVOLUTION OF THE CARNARVON TERRACE, WESTERN AUSTRALIA

Abstract

The under-explored Carnarvon Terrace is situated offshore of the Cape Range area in the Carnarvon Basin near the boundary of the Gascoyne and Exmouth Sub-basins. The stratigraphy of the area is controlled by only two wells (Pendock-1, Yardie East-1), but several onshore wells aid interpretation of seismic data.Understanding of the structural evolution of the region is facilitated by interpretation of a high-resolution non-exclusive seismic survey acquired by Geco-Prakla in 1993 (GPCTR-93 Survey).Three major tectonic stages are responsible for the structural configuration of the region:Late Palaeozoic extension in the Gascoyne Sub-basin;continental break-up between Australia and Greater India which took place along a major fracture marked by the Flinders-Long Island-Learmonth fault system active in Late Triassic and Early Jurassic times; andthe collision between Australia and Asia that commenced in Miocene times and is continuing to the present day. This event, marked by wrench and compressional structures, and often reactivation of older structures, is one of the most economically important in Australian geological history.From a regional prospectivity viewpoint at least three plays are worthy of further investigation.