Overview of the deep crustal seismic surveys conducted by Geoscience Australia through the Onshore Energy Security Program since its commencment in 2006 up to September 2009.

The Australian Geological Survey Organisation (AGSO) through the partnership in the Australian Geodynamics Cooperative Research Centre (AGCRC) and Kalgoorlie Consolidated Gold Mines (KCGM) completed a joint research project to image the crustal structure of the Kalgoorlie region to develop a knowledge of the shallow and deep structures, tectonics, and fluid migration pathways. The Australian National Seismic Imaging Resource (ANSIR) was contracted to acquire the seismic data. The project's objectives were to obtain a better understanding of - sub-surface geology at a regional and mine scale - provide more information on regional crustal thickness and major features - stratigraphic and structural architecture of the mineral system - timing and locations of fluid migration pathways The seismic survey obtained 25 km of 10 fold CMP (common midpoint) regional reflection seismic data along two traverses and 8 km of 10 fold CMP high-resolution reflection seismic data along another two traverses. The data are of good quality and similar to both the 1991 and 1999 Eastern Goldfields reflection seismic data to the north and south of the survey area. The major outcome of imaging the four localities included mapping the Golden Mile and Bolder-Lefroy Faults, and the Boorara Shear at depth. This new information indicates the Golden Mile Mine was fed by a suite of relatively minor faults dangling off the major crustal-scale Boorara Shear. The dangling element relates to percolation theory. The detachment surface was imaged on all seismic traverses. Thrust duplexes were interpreted above the detachment surface.

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.

Legacy product - no abstract available

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Abstract to be published as part of Seismix Conference Proceedings in a GA Record

Chapter in Geoscience Australia Record for the Northern Yilgarn Seismic Workshop

In 1999, a grid of five deep seismic reflection traverses was acquired within an area approximately 50 km wide by 50 km long in the Kalgoorlie Region, Eastern Goldfields Province, Yilgarn Craton. The grid tied into the existing 1991 deep seismic reflection transect (EGF1) and the 1997 high resolution and regional seismic profiles acquired by the Australian Geodynamics Cooperative Research Centre (AGCRC) and Kalgoorlie Consolidated Gold Mines (KCGM). The data were acquired to examine the geometry of the major structural features of the region, particularly the highly mineralised Bardoc Shear, and to provide three-dimensional information on granites-greenstones relationships. This paper describes the geometry of the crust and, in particular, the geometry of the granite and greenstones above the prominent regional detachment surface that occurs at about 4-6 km depth, though in one place it may extend to a depth of approximately 11 km. From the seismic, the Bardoc Shear is confirmed as west dipping and a non-planar crustal penetrating structure. The gravity modelling suggests that there is no need for the large volumes of mafic or ultramafic material previously assumed to be at depth, apart from those mapped at the surface and projected to depth.

Labuan Basin lies in deep water adjacent to the eastern Kerguelen Plateau. The basin is about 800 km long and 300 km wide and contains up to 4.5 km of sediment. A general lack of geophysical data and geological samples in this remote basin have inhibited understanding of its stratigraphy and crustal origin. Our new seismic stratigraphic interpretation of the Labuan Basin is based on deep multichennel seimic data collected by Geoscience Australia in 1997 during "Rig Seismic" surveys 179 and 180 intergrated with results of Ocean Drilling Program (ODP) Leg 183 (1998-1999)