Late Triassic – Mid-Jurassic to Neogene Extensional Fault Systems in the Exmouth Sub-Basin, Northern Carnarvon Basin, North West Shelf, Western Australia

This paper documents a detailed tectono-stratigraphic
analysis of five merged 3D seismic surveys that cover the greater
part of the Exmouth Sub-basin in the Northern Carnarvon
Basin on the North West Shelf of Australia. The Exmouth
Sub-basin is a major, NE- to NNE-trending Mesozoic to
Cenozoic depocentre within the intra-passive margin Northern
Carnarvon Basin on the North West Shelf of Australia. Late
Triassic (Rhaetian) to Middle Jurassic (Callovian) westdirected
extension produced N-S to NE-SW striking planar
domino-style extensional fault systems that formed a NNE to
NE trending rift basin, offset and segmented into 4 discrete
depocentres by E-W striking accommodation zones. Three
discrete and tectonically distinct systems of extensional faults
have been identified within the Exmouth Sub-basin:
1. Rhaetian–Callovian planar fault systems of the major rift
phase;
2. Late Berriasian–Early Valanginian post-rift, strata-bound,
planar domino fault arrays; and;
3. Late Cretaceous–Neogene polygonal fault arrays formed
during passive margin subsidence and sedimentation.
The tectono-stratigraphic evolution of the Exmouth Subbasin
is discussed and a revised model for the basin evolution
and for the development of the fault systems is presented.