Legacy product - no abstract available

Legacy product - no abstract available

No abstract available

No abstract available

This is an extended abstract prepared for the Mines and Wines conference run by SMEDG_GSNSW_AIG in Orange, NSW on 18-21 September 2007.

No abstract available

No abstract available

In 2006, deep seismic reflection profiling was carried out along six transects across the Mount Isa Inlier. The seismic lines were jointly funded by the Geological Survey of Queensland, Geoscience Australia, the Predictive Mineral Discovery Cooperative Research Centre and Zinifex Pty Ltd. (now Oz Minerals). In 2007, a further three seismic lines were collected by Geoscience Australia and the Geological Survey of Queensland from Cloncurry to south of Charters Towers via Croydon and Georgetown. This paper presents some highlights from the geological interpretations of the seismic lines.

A ~400 km long deep crustal reflection seismic survey across central Victoria, Australia, was carried out in 2006 as a collaborative project between the pmd*CRC, Geoscience Australia, the Victorian Government, Ballarat Goldfields NL, Gold Fields Australasia Pty Ltd and Perseverance Corporation Ltd, using the facilities of the National Research Facility for Earth Sounding (ANSIR). The aim was to cross several Neoproterozoic-Palaeozoic basement zones and provide information on the crustal architecture, particularly across the highly prospective Palaeozoic rocks occurring along strike to the north of the major Victorian goldfields, such as Bendigo. In the west, the Moyston Fault is a major east-dipping planar fault near the eastern edge of the Grampians-Stavely Zone, which was probably the eastern margin of continental Australia in the Cambrian. It cuts through the entire crust to the Moho. The Stawell Zone, immediately east of the Moyston Fault, has the geometry of a doubly vergent wedge. The boundary between the Stawell Zone and the Bendigo Zone farther to the east is the Avoca Fault, which appears to be a west-dipping listric fault that links to the Moyston Fault at a depth of about 22 km, forming a Y-shaped geometry. Internal faults in the Stawell and Bendigo zones are almost entirely west-dipping listric faults, which cut deep into the highly reflective lower crust, interpreted to be stacked ? Cambrian oceanic crust. Previous models advocating the presence of a mid-crustal detachment are not supported by these deep crustal scale faults. The boundary between the Bendigo and Melbourne zones, the Heathcote Fault Zone, forms a zone of strong west-dipping reflections about three kilometres wide to a depth of at least 20 km, and possibly to the Moho. The fault zone is complex and contains a boninite-tholeiite association along with blueschists in a serpentinite-matrix melange, and oceanic sedimentary rocks. The Melbourne Zone contains a deformed sedimentary pile up to 15 km thick, and contains previously unrecognised north-dipping listric faults, interpreted to be thrusts. The Governor Fault separates the Melbourne Zone from the Tabberabbera Zone and contains similar rocks to the Heathcote Fault Zone. Near the surface, the Governor Fault dips to the north at about 10°. The seismic character of the lower crust below the Melbourne Zone (the "Selwyn Block") is significantly different to that observed below the Bendigo and Stawell zones, and consists of several very strong subhorizontal reflections about 5-6 km thick starting at about 18 km depth, with a less reflective zone below it. In summary, the deep seismic data across central Victoria has allowed the geometry of the rocks and structures mapped at the surface to be projected through the entire crust, thus providing important constraints to test previous tectonic models.

The seismic stacking velocity data in the Great Australian Bight are a useful dataset for calculating depths and sediment thicknesses. This work compares these data with P-wave velocities from sonobuoys and sonic logs from wells, and on this basis a depth over-estimate of at least 15% can be expected from the depths derived from stacking velocities. Megasequence boundary depths are calculated for the Ceduna Terrace to further illustrate data quality. The database makes avaliable the unfiltered stacking velocities using conventional and horizon-consistent formats.