Geoscience Australia has been acquiring deep crustal reflection seismic transects throughout Australia since the 1960s. The results of these surveys have motivated major interpretations of important geological regions, contributed to the development of continental-scale geodynamic models and improved understanding about large-scale controls on mineral systems. Under the Onshore Energy Security Program, Geoscience Australia has acquired, processed and interpreted over 5000 km of new seismic reflection data. These transects are targeted over geological terrains in all mainland states which have potential for hydrocarbons, uranium and geothermal energy systems. The first project was undertaken in the Mt Isa and Georgetown regions of North Queensland. Interpretations of these results have identified several features of interest to mineral and energy explorers: a previously unknown basin with possible hydrocarbon and geothermal potential; a favourable setting for iron oxide uranium-copper-gold deposits; and, a favourable structural setting for orogenic gold deposits under basin cover. Other geophysical data were used to map these features in 3D, particularly into areas under cover. Seismic imaging of the full thickness of the crust provides essential, fundamental data to economic geologists about why major deposits occur where they do and reduces risk for companies considering expensive exploration programs under cover.

This service is for the 'OZTemp Interpreted Temperature at 5km Depth' image of Australia product. It includes an interpretation of the crustal temperature at 5km depth, based on the OZTemp bottom hole temperature database and additional confidential company data.

The borehole temperature data collection contains Logs recorded by Geoscience Australia from a ranges of wells and boreholes throughout Australia.

This dataset is a Gocad sgrid format of The Cooper Basin 3D Map Version 2: Thermal Modelling and Temperature Uncertainty released in August 2012 (Meixner et al., 2012). The Cooper Basin 3D Map Version 2 was produced from 3D inversions of Bouguer gravity data using geological data to constrain the inversions. The 3D map delineates regions of low density within the basement of the Cooper/Eromanga Basins that are inferred to be granitic bodies. The 3D map was originally released in two Gocad formats: surfaces and a voxet. Here it is presented as an sgrid. References: Meixner, A.J., Kirkby, A.L., Lescinsky, D.T., and Horspool, N.H., 2012. The Cooper Basin 3D map Version 2: Thermal Modelling and Temperature Uncertainty. Geoscience Australia Record 2012/60.

An extension of previously developed methods to calculate in-situ 3D temperature directly from 3D geology models in 3D GeoModeller software now allows for quantification of the uncertainty associated with those calculations. This work is being collaboratively undertaken by Intrepid Geophysics and Geoscience Australia, and will offer Australia's geothermal industry both: i) a new predictive tool helping to reduce the risk of Enhanced Geothermal System (EGS) exploration and heat resource estimation, and ii) stochastic temperature and heat flow maps of Australia.

Current understanding of the temperature distribution in the Australian continent is based on sparse and unevenly distributed borehole temperature measurements, and even fewer heat flow determinations. To address this, the Geothermal Project at Geoscience Australia (GA), initiated under the $58.9M Onshore Energy Security Program, has established a capability for determining surface heat flow across the country through temperature logging and thermal conductivity measurement. This abstract describes the GA heat flow data collection programme, its current status, and potential applications for the new data that is being collected.

Extended abstract describing metallogenic significance of georgina-Arunta seismic line. The abstract discusses mainly the Neoproterozoic and Phanerozoic mineral potential, including implications to U, Cu-Co, Au, Cu-U and energy.

The hot rock geothermal model in the Australian context comprises high-heat producing granites overlain by thick accumulations of low-thermal conductivity sediments. The granites have low concentrations of radiogenic elements, and over hundreds of millions of years, these elements decay and produce heat. The passage of this heat to the Earth's surface via upwards conduction is slowed by layers of sediments that have low thermal conductivity, creating 'hot spots' beneath the blankets. This thematic map shows granites attributed by heat production and basin depth. The majority of the granites depicted are of surface outcrop. The presence of high-heat producing granites adjacent to deep sedimentary basins may be used as a first-order indicator of where to further investigate the possibility of hot rock geothermal plays. The main frame of the map shows all granites (attributed by calculated heat production - where available), sedimentary basins (and their order e.g. where one basin is overlapped by another) and geothermal licences and applications. The top right inset map shows only those granites with a calculated radiogenic heat generation of >5 uW -3, with the depth of the sedimentary basins. This map provides a rapid view of areas that may be expected to have the greatest hot rock potential. The second-from-top inset map shows all suitable geochemical analyses from OZCHEM, attributed by calculated radiogenic heat generation. This shows both the distribution of data that goes into attributing the granite polygons, and also analyses of granites (and other rocks) that fall outside the mapped granite polygons that are otherwise excluded from the main map. The third-from-top inset map shows the distribution of drillholes with temperature measurements. The bottom inset map shows an image of the Austherm07 database, which is derived from the drillhole temperature information. The image shows the projected temperature of the crust at a depth of 5 kilometres, interpolated between the drillholes. Overlain on this image is the small number of publicly-available heat flow data.

The hot rock geothermal model in the Australian context comprises high-heat producing granites overlain by thick accumulations of low-thermal conductivity sediments. The granites have low concentrations of radiogenic elements, and over hundreds of millions of years, these elements decay and produce heat. The passage of this heat to the Earth's surface via upwards conduction is slowed by layers of sediments that have low thermal conductivity, creating "hot spots" beneath the blankets. This thematic map shows granites attributed by heat production and basin depth. The majority of the granites depicted are of surface outcrop. The presence of high-heat producing granites adjacent to deep sedimentary basins may be used as a first-order indicator of where to further investigate the possibility of hot rock geothermal plays. The main frame of the map shows all granites (attributed by calculated heat production where available), sedimentary basins and their order (e.g. where one basin is overlapped by another) and geothermal licenses and applications. The top right inset map shows only those granites with a calculated radiogenic heat generation of >5 Wm-3, and the depths of the sedimentary basins. This map provides a rapid view of areas that may be expected to have the greatest hot rock potential. The second-from-top inset map shows all suitable geochemical analyses from OZCHEM, attributed by calculated radiogenic heat generation. This shows both the distribution of data that goes into attributing the granite polygons, and also analyses of granites (and other rocks) that fall outside the mapped granite polygons and are otherwise excluded from the main map. The third-from-top inset map shows the distribution of drillholes that have temperature measurements. The bottom inset map shows an image of the Austherm07 database, which is derived from the drillhole temperature information. The image shows the projected temperature of the crust at a depth of 5km, interpolated between the drillholes. Overlain on this image is the small number of publicly-available heat flow data. This map is GA GeoCat record 65306. ISBN (print): 978-1-921236-44-0; ISBN (web): 978-1-921236-45-7. Webpage: http://www.ga.gov.au/minerals/research/national/geothermal/index.jsp.

The economic viability of geothermal energy depends on the depth that must be drilled to reach the required temperature. This depends on the geothermal gradient, which varies vertically and horizontally in the Earth's crust. Traditionally these variations in geothermal gradient have been interpreted in terms of thermal conduction. However, advection and convection influence the temperature distribution in some sedimentary basins. Convection can cause the temperature gradient to vary significantly with depth, such that temperature estimates derived from extrapolation of shallow temperature gradients could be misleading. We use borehole temperature measurements in the Perth Basin (Western Australia) and the Cooper Basin (South Australia and Queensland) to reveal spatial variations in the geothermal gradient, and consider whether these patterns are indicative of convection.