The basin covers an area of 150,000 square kilometers and spans from southeastern South Australia to southwestern Victoria, with 80% lying offshore in water depths ranging from 50-3,000 meters.

Renewed rifting in the late Cretaceous was driven by a change in crustal extension style from north-south to northeast-southwest resulting in the structurally different, northwest-southeast trending Torquay, Morum, Nelson, and Hunter Sub-basins in the mid- and off-shore.

This rifting phase is marked by a change in crustal extension direction from north-south to northeast-southwest resulting in the deposition of large and deep depocenters in the mid- and off-shore basin.

As Australian-Antarctic plate clearance continued and the passive margin developed further the basin experienced widespread thermal subsidence leading to an increase in accommodation space.

Deposition from the late Maastrichtian to present day is marked by a succession of marine and carbonate accumulations of the Wangerrip, Nirranda, Heytesbury, and Whalers Bluff Groups, separated by distinct unconformities associated with basin-wide compression events.