Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

The breakup of Gondwana during the Mesozoic resulted in widespread basin formation along Australia's southern margin, of which the Bight Basin is a component. In contrast to many other extensional margins, the Australian southern margin has been classified as a non-volcanic rifted margin, despite the reported occurrence of scattered volcanic and intrusive rocks in the geological literature. Public release of the Flinders 2D seismic survey data in the Bight Basin has allowed the accurate mapping of widespread sills, dykes, lava flows and volcanoes.

A detailed sequence stratigraphic study has been undertaken on the three wells in the Houtman Sub-basin: Gun Island 1, Houtman 1 and Charon 1. The study focussed on the Early-Late Jurassic Cattamarra Coal Measures, Cadda Formation and Yarragadee Formation succession. Wireline log character, cuttings, sidewall core and conventional core lithologies and palynological data were used to identify facies and paleoenvironments. Palynology for all wells has been reviewed, including new data collected by Geoscience Australia for Gun Island 1. Facies stacking patterns were used to define systems tracts and subsequently ten third-order depositional sequences. At the second-order (supersequence) level, the Cattamarra Coal Measures record a transgression culminating in maximum flooding in the Cadda Formation followed by highstand aggradation and regression in the Yarragadee Formation. The third-order sequences characterised in this study overprint this supersequence and control the local distribution of facies. The relative dominance of a facies may be either enhanced or diminished depending upon its position within the larger second-order supersequence. For example, a number of transgressive systems tracts within the dominantly non-marine Yarragadee Formation and Cattamarra Coal Measures record multiple, dinocyst-bearing, minor marine incursions into the Houtman Sub-basin. These marine incursions are not evident in the Yarragadee Formation in Charon 1, indicating a lack of accommodation space or proximal sediment input in the north during the mid-late Jurassic. The combined influence of these third-order and second-order sequences on facies distribution has significant implications for the distribution of potential reservoirs and seals in the Houtman Sub-basin and for regional palaeogeographic reconstructions of the Perth Basin.

This report was Commissioned by Geoscience Australia for the Western Tasmania Regional Minerals Program (WTRMP). It was completed by SRK Consulting, and is listed as Report AG701. The report covers the interpretation of economic basement in the Bass Basin, and documents the production of a SEEBASE model.

Legacy product - 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.

Under the Australian Government's Offshore Energy Program, Geoscience Australia conducted a marine reconnaissance survey GA2476 from October 2008 to January 2009 using the German research vessel RV Sonne. The 90-day marine reconnaissance survey acquired geological and geophysical data over poorly known areas of the Zeewyck and Houtman sub-basins (Perth Basin); the southern Exmouth Sub-basin and Bernier Platform (southern parts of the Carnarvon Basin); and the Cuvier Plateau (also referred to as the Wallaby Plateau). A total of 68 sampling operations recovered rocks during the survey, including 19 over the Zeewyck Sub-basin, 19 over the Houtman Sub-basin, 15 over the southern Exmouth Sub-basin, 13 over the Cuvier Plateau and two over the Bernier Platform. Geological sampling operations were undertaken in water depths ranging from 1,000 to 5,000 m. Fifty-one dredge, 13 grab and three benthic sled hauls as well as one box core recovered several hundred individual rock samples. These rock samples represent the first successful recovery of rock dredges from the Houtman Sub-basin and supplement previous sparsely sampled rocks from frontier Zeewyck Sub-basin, southern Exmouth Sub-basin, Bernier Platform and Cuvier Plateau. The rock hauls yielded a diverse range of rock lithologies including sandstone, claystone, siltstone, mudstones, limestone and minor basalt. Initial micropalaeontological analyses (foraminifera, nannofossils and palynology) of rock samples from the Houtman, Zeewyck and Exmouth sub-basins and the Bernier Platform have shown that most samples fall within two broad stratigraphic intervals: early Cretaceous strata and middle Paleocene to late Eocene strata. For the first time, terrestrial marine sedimentary rocks have been recovered from the southwestern escarpment of the Cuvier Plateau. At least one sample is likely to be Upper Jurassic, making it the oldest known sedimentary sample from the Cuvier Platform.