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  • The Bland Basin is the broad alluviated palaeovalley of Bland Creek, a tributary of the Lachlan River in the central part of New South Wales, Australia, within the drainage basin of the Murray-Darling River System. It covers about 4000 km2 and contains up to 120 m of terrestrial sediments, interpreted as being deposited by alluvial, colluvial, lacustrine/paludal, and aeolian processes. It is undated, but is likely to be coeval with the downstream contiguous fill of the Lachlan River palaeovalley, dated elsewhere by palynology as Miocene to Recent. The southwestern part of the basin has been studied in detail using airborne geophysics (electromagnetics, magnetics, and gamma ray spectrometry) and drilling. The small erosional catchment area of the modern Basin surface has resulted in a paucity of sediment available for deposition in the Basin, but drainage base level has been driven by the rate of sedimentation of the Lachlan palaeovalley downstream of the Basin. Therefore, most of the sediment derived from the catchment has been trapped in the Basin rather than being transported downstream and into the Lachlan palaeovalley, and at times large lakes and/or swamps have formed in the central part of the Basin. The sediments in the southwest of the Basin are dominated by clay and silt, with local sand and gravel, mostly in basal gravelly sand and a sandier interval in the middle part of the sequence. Quartz silt derived from aeolian dust is a major component of the upper part of the sedimentary sequence. Geophysical responses of the sediment include high conductivity due to saline groundwater, low gamma response dominated by thorium decay emissions due to the leached nature of the sediment, and short wavelength-low amplitude magnetic anomalies resulting from local concentrations of detrital maghemite-rich gravel formed during weathering in the catchment area. Other broad valleys draining to the Lachlan River may contain similar mud-dominated Neogene basins.

  • 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 movie flythrough displaying various geological and geophysical data used for petroleum prospectivity assessment of the offshore northern Perth Basin

  • In mid 2011 the Australian Government announced funding of a new four year National CO2 Infrastructure Plan (NCIP) to accelerate the identification and development of sites suitable for the long term storage of CO2 in Australia that are within reasonable distances of major energy and industrial CO2 emission sources. The NCIP program promotes pre-competitive storage exploration and provides a basis for the development of transport and storage infrastructure. The Plan follows on from recommendations from the Carbon Storage Taskforce and the National CCS Council (formerly, the National Low Emissions Coal Council). It builds on the work funded under the National Low Emissions Coal Initiative and the need for adequate storage to be identified as a national priority. Geoscience Australia is providing strategic advice in delivering the plan and will lead in the acquisition of pre-competitive data. Four offshore sedimentary basins (Bonaparte, Browse, Perth and Gippsland basins) and several onshore basins have been identified for pre-competitive data acquisition and study. The offshore Petrel Sub-basin is located in Bonaparte Basin, in NW Australia, has been identified as a potential carbon storage hub for CO2 produced as a by-product from future LNG processing associated with the development of major gas accumulations on the NW Shelf. The aim of the project is to determine if the sub-basin is suitable for long-term storage, and has the potential capacity to be a major storage site. The project began in June 2011 and will be completed by July 2013. As part of the project, new 2D seismic data will be acquired in an area of poor existing seismic coverage along the boundary of the two Greenhouse Gas Assessment Areas, which were released in 2009.

  • This paper presents tectonic elements maps for the continental margin of East Antarctica, from 38-164E, together with brief descriptions of all the major tectonic elements.

  • In 2008-09, under the Offshore Energy Security Program, Geoscience Australia (GA) acquired 800 km of 2D seismic (Southwest Margin seismic survey) along with regional gravity and magnetic data (Southwest Margin Marine Reconnaissance survey) in the southern Carnarvon Basin. Data acquisition targeted the western Bernier Platform, as well as the adjoining poorly explored deepwater (>500m) parts of the margin, where prominent gravity lows indicated likely southern extension of the Exmouth Sub-basin and northern extension of the Houtman Sub-basin. The 2011 Acreage Release areas in the frontier part of the southern Carnarvon Basin are about the same size as the combined Rankin Platform, Barrow and Dampier Sub-basins. Only two wells (Pendock 1A and Herdsman 1) have been drilled in and in close proximity to these Acreage Release areas, providing only limited information on stratigraphy and petroleum systems of the region. The newly acquired seismic and potential field data were used to evaluate structure, stratigraphy and petroleum potential of the area. Analysis of the seismic data resulted in better understanding of tectonic and depositional history, including the role of extensive Early Cretaceous volcanism. Sufficient sediment thickness and a wide-range of possible structural and stratigraphic plays have been identified in the 2011 Acreage Release areas.

  • The 2008 Rankins Springs Seismic Survey was a joint initiative by Geoscience Australia and NSW Department of Primary Industries under the Onshore Energy Security Program (OESP) in the under-explored southeastern Darling Basin. Regional acquisition parameters of 300 channels, 40 m group interval and 80 m vibration point interval nevertheless allowed detailed imaging of a 3 second (TWT) thick sedimentary sequence in the Yathong Trough. Use of three 12 second vari-sweeps from truck mounted Hemi 50 (50,000 lb) vibrators provided sufficient energy to image from immediately below regolith to the Moho. The sweep frequency ranges 6 - 64, 10 - 96 and 8 - 80 Hz were chosen both for deep penetration and high resolution in the sedimentary section. In-field processing produced a high quality preliminary section on a daily basis using an iterative process of automatic residual statics calculation on a deep gate and interactive stacking velocity analysis. Both automatic statics and stacking velocity were essential for successful imaging, but velocity was more important, as initial estimates based on first arrival velocities produced a degraded section. The field seismic section clearly shows a fault bounded trough, with evidence of compressional structures in the upper part and hints of underlying older sedimentary basins. The in-field stacking velocity analysis also provided immediate evaluation of the maximum depth of the trough, namely 6 km, deeper than expected. Efficient in-field processing allows early notification to project partners of a successful survey, facilitating future planning, and provides a sound basis for streamlined subsequent processing.

  • Over the last five years, the Onshore Energy Security Program, funded by the Australian Government and conducted by Geoscience Australia, has acquired deep seismic reflection data, in conjunction with state and Territory geological surveys, across several frontier sedimentary basins to stimulate petroleum exploration in onshore Australia. Here, we present data from two seismic lines collected in Western Australia in 2011. The Yilgarn-Officer-Musgrave (YOM) seismic line, 487 km long, crossed the western Officer Basin in Western Australia, and the Southern Carnarvon Seismic line, 259 km long, crossed the Byro Sub-basin of Southern Carnarvon Basin. The YOM survey aims to image the Neoproterozoic to Devonian western Officer Basin, one of Australia's underexplored sedimentary basins with hydrocarbon potential. The survey data will also build on the geoscientific knowledge of the architecture of Australia's crust and the relationship between the eastern Yilgarn Craton and the Musgrave Province. The Southern Carnarvon survey aims to image the in the onshore section of the Ordovician to Permian Carnarvon Basin, which offshore is one of Australia's premier petroleum producing provinces. The Byro Sub-basin is an underexplored depocentre with the potential for both hydrocarbon and geothermal energy. Where the seismic crosses the Byro Sub-basin it images a pair of half graben on west dipping faults. Structural and sequence stratigraphic interpretations of the two seismic lines will be presented here.

  • The Early Permian to Middle Triassic Bowen and Gunnedah basins in eastern Australia developed in response to a series of interplate and intraplate tectonic events located to the east of the basin system. The initial event was extensional and stretched the continental crust to form part of the major Early Permian East Australian Rift System that stretched at least from far north Queensland to southern New South Wales. The most commercially important of the rift-related features are a series of half graben that form the Denison Trough, now the site of several producing gas fields. The eastern part of the rift system commenced at about 305 Ma and was volcanic dominated. In contrast, the half graben in, and to the west of, the Bowen Basin were non-volcanic, and appear to have initiated at about 285 Ma. These half graben are essentially north-south in length with an extension direction of approximately east-northeast. Mechanical extension appears to have ceased at about 280 Ma, when subsidence became driven by thermal relaxation. The extension occurred in a backarc setting, in response to far field stresses that propagated from the west-dipping subduction system at the convergent plate margin of East Gondwana that was located to the east of the East Australian Rift System.

  • The Onshore Energy Security Program, funded by the Australian Government, Geoscience Australia has acquired deep seismic reflection data across several frontier sedimentary basins to stimulate interest in petroleum exploration in onshore Australia. Detailed interpretation of deep seismic reflection profiles from four onshore basins, focusing on overall basin geometry and internal sequence stratigraphy will be presented here, with the aim of assessing the petroleum potential of the basins. At the Southern end of the exposed part of the Mt Isa Province, northwest Queensland, a deep seismic line (06GA-M6) crosses the Burke River Structural Zone of the Georgina Basin. The basin here is >50 km wide, with a half graben geometry, and bound in the west by a rift border fault. The Millungera Basin in northwest Queensland is completely covered by the thin Eromanga basin and was unknown prior to being detected on two seismic lines (06GA-M4 and 06GA-M5) acquired in 2006. Following this, seismic line 07GA-IG1 imaged a 65 km wide section of the basin. The geometry of internal stratigraphic sequences and post-depositional thrust margin indicate that the original succession was much thicker than preserved today. The Yathong Trough in the southeast part of the Darling Basin in NSW has been imaged in seismic line 08GA-RS2 and interpreted in detail using sequence stratigraphic principles, with several sequences being mapped. The upper part of this basin contains Devonian sediments, with potential source rocks at depth.