The Ceduna Sub-basin of the deep-water frontier Bight Basin contains a Middle Jurassic-Late Cretaceous sedimentary succession in excess of 15 km thick. Nine offshore exploration wells have been drilled in the basin, mostly clustered around the inboard edge of the Ceduna Sub-basin. As a result, the distal mid-Late Cretaceous strata predicted to contain potential source rock facies, had previously not been sampled. The presence of high quality source rocks in the basin was therefore an open question. 2D seismic data was used to delineate targets for sampling of the pre-Campanian section of the basin. Identified targets included potential source intervals of Albian-Santonian age at locations on the seaward edge of the Ceduna and Eyre Terrace where canyon formation, slumping and faulting have exposed the section. Also, a series of sites were selected to test for potential hydrocarbon seepage in the basin. These sites include areas where recently reactivated deep-seated faults were exposed at the seafloor, basin margin areas where facies thin, and areas where possible seepage was identified from Synthetic Aperture Radar (SAR) data. In February and March 2007, a 3-week marine acquisition programme was carried out on the RV Southern Surveyor. Potential dredge targets were first surveyed with 30 kHz EM300 swath bathymetry and observed with Topaz 3.5 kHz sub-bottom profiler. Near-live swath processing and slope analysis techniques enabled site specific dredge sampling of seafloor terrains where Cretaceous section outcropped or slopes were sufficient to ensure only a thin cover of overlying sediments. Targets include fault scarps and eroded sides of canyons. A better-than-expected number of successful dredges were collected (total of 37) from water depths ranging from 1600-4500m. Geochemical analysis of 259 dredge samples for total organic carbon (TOC) and pyrolysis yields (Rock Eval) identified good to very good organic richness in 13 samples, with TOC values between 2.1% and 6.2%. Of these, seven show liquids potential with Hydrocarbon Index (HI) values ranging between 274 and 479 (mgHC/TOC). The rocks with the best source rock characteristics came from high priority sampling sites in the westernmost Ceduna Sub-basin. Organic geochemical analysis has provided evidence for preservation of organic matter under anoxic conditions close to or at the sediment-water interface. Biostratigraphic analysis of these organic-rich rocks has yielded an age around the Cenomanian-Turonian boundary. Although the dredged rocks are immature for hydrocarbon generation, interpretation of an extensive seismic grid across the basin and petroleum system modelling have shown that this succession occurs with the oil window in the central Ceduna Sub-basin. The results of this study provide the best evidence to date for the presence of good quality liquids-prone source rocks in the basin, successfully addressing a key industry concern in this petroleum exploration frontier.

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.

These preliminary notes deal with the sequence as it is found in the Giralia Structure. The analysis of the Cretaceous-Tertiary megafauna is described. The findings of the investigation with respect to the sedimentary sequence are discussed.

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.

This glossary gives a brief description of the more important sedimentary rocks. Composition percentages are tentative in nearly all cases. The terms listed are classified as follows.

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This dataset is a pre-release copy of the Australian Geological Provinces Database. The dataset is the best available national coverage of geological provinces as at 1 November 2012. The dataset is not entirely complete for the whole of Australia, and has not undergone complete and rigorous QA/QC. This interim dataset is provided for use only by Geoscience Australia staff and their approved collaborators. The Australian Geological Provinces Database contains descriptions and polygon outlines of geological provinces of the Australian continent and the surrounding marine jurisdictional area. Province types include sedimentary basins, basement tectonic provinces, igneous provinces, and metallogenic provinces. Descriptive attributes include sedimentary, igneous and structural characteristics, age limits, parent and constituent units, relations to surrounding provinces, and mineral and petroleum resources. The province outlines are typically compiled from source data at around 1:1,000,000 scale, which may include outcrop mapping, drilling, and geophysical data. Province boundaries have a spatial accuracy of around 500 metres at best (ie, where constrained by outcrop), but where province boundaries are concealed and are interpreted only from geophysical or drilling data, spatial accuracy may be in the order of 1 km to greater than 10 km. Attribution of province boundaries with information about data source and accuracy is incomplete in this version of the dataset.

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