| Summary: | Typescript Thesis (PhD) -- University of Melbourne, Faculty of Science, 2006 Includes bibliographical references (leaves 196-206) The Otway Basin formed during Late Jurassic�Late Paleocene rifting and separation of the Australian and Antarctic continents. Rifting proceeded from west to east, and by the end of the Early Cretaceous the intra-cratonic rift stretched from the Indian Ocean in the west to the eastern side of the Gippsland Basin to the east. During the Late Cretaceous, the architecture changed in the east-central Otway Basin as the rift axis began to propagate to the south, along the western margin of Tasmania, creating a NNW-SSE trending left-lateral oblique transform margin. The change caused decreased extension and the eventual abandonment of the Bass Basin rift segment as Tasmania remained attached to the Indo-Australian Plate. Previous workers have hypothesized that the development of the oblique margin was controlled by the extensional reactivation of the N-S trending lithospheric- scale suture between the Palaeozoic Lachlan and Delamerian mobile belts. The Shipwreck Trough is located along strike of the Palaeozoic suture, at the northern tip of the Late Cretaceous oblique margin, and has been the location of numerous recent natural gas discoveries. These discoveries have driven the acquisition of high-resolution 3D seismic data sets making the Shipwreck Trough an ideal location to study the structural development of this oblique rift margin. This study has illuminated the evolution of the Shipwreck Trough through 3D structural mapping of seismic horizons, faults, and growth strata geometry and distribution. The Shipwreck Trough evolved through two rift phases. Commencing in the Late Jurassic-Barremian, the N-S trending Proto-Shipwreck Trough and NE trending Minerva Graben, Princetown Horst, and Geographe Horst were formed by the probable extensional reactivation of NE and NNW trending Palaeozoic basement structures. These early Cretaceous depocentres were filled with up to 4 km of ...
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