Publication Name: PESA's Eastern Australasian Basin Symposium II
Authors: A.A. Krassay, D.L. Cathro and D.J. Ryan
Date Published: December 2004
Number of Pages: 37
Reference Type: Book Section
Abstract:
A new sequence stratigraphic framework has been developed for the Otway Basin based on the interpretation and integration of offshore wells, key onshore wells, new biostratigraphic results and a regional grid of 2D seismic data.In the new tectonostratigraphic framework, seven major basin phases and their eight component supersequences are recognised as follows: 1) Tithonian?-Barremian rifting of the Crayfish Supersequence, 2) Aptian-Albian post-rift deposition of the Eumeralla Supersequence, 3) mid-Cretaceous compression and inversion, 4) Late Cretaceous rifting of the Shipwreck and Sherbrook Supersequences, 5) latest Maastrichtian to Middle Eocene basin reorganisation and early thermal subsidence of the Wangerrip Supersequence, 6) local inversion and thermal subsidence of the Nirranda Supersequence (Middle Eocene to Early Oligocene), followed by thermal subsidence and progressive compression of the Heytesbury Supersequence (Late Oligocene to Late Miocene), leading to Late Miocene uplift and erosion and 7) PlioPleistocene deposition of the Whalers Bluff Supersequence.
Basin phases are distinguished by their different tectonic driving mechanisms as the primary control on the creation of accommodation space. The supersequences are bounded by regional unconformities and define major episodes of sedimentation within each basin phase. Supersequences are related to second-order transgressive-regressive cycles within the basin and are regionally mappable. The new sequence stratigraphic framework is then used as the basis for correlation to deep-water regions where well-control is limited or absent. The framework is also used to help place existing, complex, facies-dependent lithostratigraphic schemes into depositional and petroleum systems context.