The Capel and Faust basins lie at water depths of 1,500-3,000 m 800 km east of Brisbane. Geoscience Australia began a petroleum prospectivity study of these remote frontier basins with the acquisition of 2D geophysical data (seismic reflection, refraction, gravity, magnetic, multi-beam bathymetry) across an area of 87,000 km2 during 2006/07. The approach mapped the complex distribution of sub-basins and determined sediment thickness through integration of traditional 2D time-domain seismic interpretation techniques with 3D mapping, visualisation and gravity modelling. Forward and inverse 3D gravity models were used to inform the seismic interpretation process and test the seismic basement pick. Gravity models had three sediment layers with inferred average densities of 1.85, 2.13, 2.31 t/m3 overlying a pre-rift basement of density 2.54 t/m3, itself considered to consist of older basin material evidently intruded by igneous rocks. Conversion of travel times of interpreted seismic horizons to depth domain was achieved using a quadratic function derived from ray-tracing forward modelling of refraction data supplemented by stacking interval velocities, and densities for gravity modelling were inferred from the same velocity models. These models suggest sediment of average velocity 3.5 km/s reaches a thickness exceeding 6 km in the northwest of the area, and for the first time mapped the extent and depth of sediment in these basins. The results of the study have confirmed that sediment thickness in the Capel and Faust basins is sufficient in places for potential petroleum generation.

Geoscience Australia is conducting a study under the National Carbon Infrastructure Plan (NCIP) to assess the suitability of the Vlaming Sub-basin for CO2 storage. It involves characterisation of the Valanginian reservoir (Gage Sandstone) and the Early Cretaceous seal (South Perth Shale) by integrating seismic interpretation and well log analysis in a detailed sequence stratigraphic investigation. The Gage Sandstone, comprised of channelised turbidites and mass flows, was the first unit deposited after breakup between India and Australia. Deposited during a sea level lowstand in the palaeo-topographic lows of the breakup unconformity, it is overlain by a thick deltaic to shallow marine succession of the South Perth Shale. The Gage Sandstone is considered one of the best reservoirs in the sub-basin with porosities of 23-30% and permeabilities of 200-1800 mD. It occurs at depths between 1000 and 3000 m below the seafloor, which makes, it an attractive target for the injection and long-term storage of supercritical CO2. The new extent of the Gage Sandstone, based on seismic interpretation and well log correlation, shows that in some of the wells the sandstone unit overlying the Valanginian unconformity belongs to the South Perth Shale and not to the Gage Sandstone. The G. Mutabilis palynological zone used in the past for identifying Gage Sandstone interval appears to be facies controlled and time transgressive. Detailed analysis of the reservoir properties at the wells in conjunction with systematic seismic facies mapping will serve as a basis for a regional reservoir model and storage potential estimation of the Gage Sandstone reservoir.

A deep seismic reflection profile was acquired in South Australia and Victoria in November 2009 by Geoscience Australia with project partners AuScope, Geoscience Victoria, and Primary Industries and Resources South Australia (PIRSA). Along with previously acquired deep seismic reflection data, this 145 km long line completes a continuous east-west transect across the eastern Delamerian Fold Belt into the western Lachlan Fold Belt. The project aims included determining tectonic vergence during and after amalgamation of the Gondwana Supercontinent, understanding the transition from passive margin (Rodinia breakup) to convergent margin (Tasmanides orogenesis), and locating the so-called 'Tasman Line', the extent of Proterozoic continental crust.

The Palaeoproterozoic to Mesoproterozoic (<1850-<1490 Ma) southern McArthur Basin, Northern Territory, Australia, contains an unmetamorphosed, relatively undeformed succession of carbonate, siliciclastic and volcanic rocks that host the McArthur River (HYC) Zn-Pb-Ag deposit. Seismic reflection data obtained across this basin have the potential to revolutionise our understanding of the crustal architecture in which this deposit formed. These data were collected in late 2002 as part of a study to examine the fundamental basin architecture of the southern McArthur Basin, particularly the Batten Fault Zone, and the nature of the underlying basement. Geoscience Australia, the Northern Territory Geological Survey and the Predictive Mineral Discovery Cooperative Research Centre combined to acquire an east-west deep seismic reflection profile (line 02GA-BT1) approximately 110 km long, commencing 15 km west of Borroloola, and extending westwards along the Borroloola-Roper Bar road to the Bauhinia Downs region (Fig. 1). A short 17 km north-south cross line (02GA-BT2) was also acquired in collaboration with AngloAmerican. The seismic data were acquired through the Australian National Seismic Imaging Resource (ANSIR).

Seismic reflection, seismic refraction and portable broadband data collected within Western Australia's Yilgarn Craton, in particular the Eastern Goldfields Province, are providing detailed images of several of its highly mineralized terranes as well as new insights into the crustal architecture of the region. When the results from these seismic techniques are integrated, the results are providing a better understanding of the structure of the crust and lithosphere beneath the Yilgarn Carton, from the surface to depths in excess of 300 km.

This article presents the results of studies in North Queensland associated with the 2007 Mt Isa-Georgetown-Charters Towers seismic survey. Results include seismic interpretation, geophysical studies and 3D maps, tectonic and metallogenic syntheses and energy potential assessment.

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.

Seismic line 07GA-IG1, described here, forms part of the Isa-Georgetown-Charters Towers seismic survey that was acquired in 2007. The seismic line is oriented approximately northeast-southwest and extends from northwest of Cloncurry in the southwest to east of Croydon in the northeast (Figure 1). The acquisition costs for this line were provided jointly by Geoscience Australia and the Geological Survey of Queensland, and field logistics and processing were carried out by the Seismic Acquisition and Processing team from Geoscience Australia. Six discrete geological provinces have been interpreted on this seismic section (Figure 2). Two of these, the Numil and Abingdon Provinces, only occur in the subsurface. The Mt Isa Province occurs in the southwest, with the Kowanyama Province occurring on the middle of the section and the Etheridge province in the northeast. The Millungera Basin, first observed on two seismic lines in the 2006 Mt Isa seismic survey, occurs beneath shallow cover of the Jurassic-Cretaceous Carpentaria Basin and sits above the Kowanyama Province.

This report presents results from a pilot study conducted within the northern part of the Great Australian Bight, focusing primarily on the Eyre Sub-basin. The aim of the study was to develop and test a methodology for creating petroleum prospectivity maps based primarily on the extent of sealing lithologies. The Eyre Sub-basin provides a good basis for this study due to the good seismic coverage and lithological data provided from eight ODP holes and an Esso petroleum exploration well (Jerboa-1). Well data are used to determine which sequences contain potential sealing lithologies, while seismic data are used to map out the extent and distribution of potential sealing sequences across the study area. The regional extent of sealing units to their first pinch-out is used as a first-order assessment of petroleum prospectivity. Results from Jerboa-1 show that there is a proven oil source and adequate reservoir facies with seal and trap integrity being the major play risks. Mesozoic sediments provide the primary potential sealing units across this region and have greatest thickness across the Eyre Sub-basin. To the west and north of this sub-basin, the distribution of the Mesozoic sediments is discontinuous, resulting in lower sealing potential. Mesozoic sediments are absent within the Eucla Inlier immediately north of the Eyre Sub-basin, resulting in very low sealing potential. Three categories of petroleum prospectivity have been determined in this study. Good prospectivity has been assigned up to the limits of the thick and continuous Mesozoic sediments in the Eyre Sub-basin. Low prospectivity has been assigned to the western Apollo Shelf, reflecting the reliance on relatively thin and discontinuous Mesozoic seals and the poor seal potential of Tertiary age carbonates. The Eucla Inlier is designated as a non-prospective area due to the absence of Mesozoic sediments and any potential sealing units for Tertiary age reservoirs.

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.