REVIEW OF RECENT RESULTS FROM CONTINENTAL DEEP SEISMIC PROFILING IN AUSTRALIA

The Australian Geological Survey Organisation regularly collects 450-5 00 km of onshore deep seismic reflection data and up to 4500 km offsho re each year in Australia. These recordings are made in a wide range o f tectonic provinces, including, in the last few years, late Palaeozoi c-Mesozoic intracontinental and Palaeozoic-Mesozoic-Cenozoic continent al margin extensional basins, moderately deformed Palaeozoic transtens ional basins and compressional fold belts, and Archaean greenstone ter ranes. Several of these provinces are major petroleum exploration prov inces, whereas others contain significant mineral deposits. The primar y purpose of the deep seismic profiling program is to resolve the tect onic history of the Australian continent, and thereby to encourage exp loration for hydrocarbons and mineral resources in Australia. On the n orthwest Australian continental margin, major basin systems including the Bonaparte Basin, formed as a result of complex interactions since the Carboniferous, involving episodes of extension followed by strike- slip movements and inversion, which reactivated both the primary exten sional and ancient basement structures. Off southeastern Australia, ba sins such as the Gippsland Basin formed as part of a linked transtensi onal system related to movement on a common mid-crustal detachment com plex. On continental Australia, the Bowen Basin, in the northeast, was deformed by thrust faults that root in a major E-dipping detachment t hat flattens in the middle crust. The Cobar Basin, in the southeast, i s a case where the seismic data support a detachment model in which th e upper plate displacement vector can be calculated by plate reconstru ctions linking the geometry of the detachment surface with that of the basin. The greenstone terranes within the Eastern Goldfields region o f Western Australia show crustal-scale fault systems that are planar a nd steep dipping, more in keeping with those interpreted in data from other Precambrian provinces rather than those of the Palaeozoic provin ces.