The Australian Geothermal Association compiled data on the installed capacity of direct-use geothermal and geoexchange systems in Australia, including large-scale ground source heat pumps and hot sedimentary applications through to December 2018. Large-scale direct-use hot sedimentary aquifer systems includes systems to heat swimming pools or provide hydronic heating systems. In geoexchange systems, the Earth acts as a heat source or a heat sink, exploiting the temperature difference between the surface (atmosphere) and at depth. The temperature of the Earth just a few metres below the surface is much more consistent than atmospheric temperature, especially in seasonal climates. These resources do not require the addition of geothermal heat.

Geothermal energy is a renewable energy technology reported to have a large potential resource base. However, existing geothermal data for Australia (borehole temperatures and heat flow determinations), are limited and collection of additional data is both time consuming and restricted to accessing to wells drilled for other purposes. It is therefore important to develop "deposit" or resource models to aid exploration; improving the quality of subsurface thermal estimates, and helping to identify the distal footprints of geothermal systems. Conceptually, the fundamental requirements of a geothermal system are well understood. However, the complex interplay between the various elements makes it difficult to compare different geographical regions and to assess their relative prospectively. As such, the results of some 130,000 synthetic thermal-modelling runs have been used to calibrate a new tool called the 'Geothermal Calculator'. The Calculator acts as an emulator, or surrogate model, falling into a class of functions which seek to approximate the input / output behaviour of more-complex systems. This presentation will explore the mechanics of the Calculator, before examining some of its possible uses; from simple point-spot estimates to the broader continental scale. The functionality of the Geothermal Calculator presents a significant step forward in our ability to produce subsurface temperature estimates, and represents a notable milestone in the pathway to realising our subsurface geothermal energy potential.

<div>This report presents thermal property data (thermal conductivity data, calculated heat production data, and calculated surface heat flow) from the deep (1751 m) stratigraphic drill hole, NDI Carrara 1. Thermal conductivity analyses were undertaken at the University of Melbourne. Heat production values were calculated from existing whole rock geochemical data. Surface heat flow was determined using the laboratory thermal conductivity data together with in situ downhole temperature data collected previously.</div>

The Geoscience Australia Rock Properties database stores the result measurements of scalar and vector petrophysical properties of rock and regolith specimens and hydrogeological data. Oracle database and Open Geospatial Consortium (OGC) web services. Links to Samples, Field Sites, Boreholes. <b>Value:</b> Essential for relating geophysical measurements to geology and hydrogeology and thereby constraining geological, geophysical and groundwater models of the Earth <b>Scope:</b> Data are sourced from all states and territories of Australia

<div><strong>Output Type: </strong>Exploring for the Future Extended Abstract</div><div><br></div><div><strong>Short Abstract: </strong>The thickness and thermal structure of continental lithosphere influences the location of seismic and volcanic hazards and is important for predicting long-term evolution of landscapes, sedimentary basins, and the distribution of natural resources. In this project, we have developed new, continental-scale models of the thermomechanical structure of the Australian plate. We begin by compiling an inventory of >15,000 geochemical analyses of peridotitic xenoliths and xenocrysts from across the continent that have been carried up to the surface in volcanic eruptions. We apply thermobarometric techniques to constrain their pressure and temperature of equilibration and perform steady-state heat flow modelling to assess the paleogeotherm beneath these sites. We subsequently use the paleogeotherms as constraints in a Bayesian calibration of anelasticity at seismic frequencies to provide a mapping between seismic velocity and temperature as a function of pressure. We apply this method to several regional-scale seismic tomography models, allowing the temperature to be continuously mapped throughout the Australian lithospheric and asthenospheric mantle. Our models include assessment of uncertainties and can be used to query thermomechanical properties, such as lithospheric thickness, heat flow through the Moho, and the Curie depth.</div><div><br></div><div><strong>Citation: </strong>Hoggard, M.J., Hazzard, J., Sudholz, Z., Richards, F., Duvernay, T., Austermann, J., Jaques, A.L., Yaxley, G., Czarnota, K. & Haynes, M., 2024. Thermochemical models of the Australian plate. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra. https://doi.org/10.26186/149411</div>

<div>Diamond exploration over the past decade has led to the discovery of a new province of kimberlitic pipes (the Webb Province) in the Gibson Desert of central Australia. The Webb pipes comprise sparse macrocrystic olivine set in a groundmass of olivine, phlogopite, perovskite, spinel, clinopyroxene, titanian-andradite and carbonate. The pipes resemble ultramafic lamprophyres (notably aillikites) in their mineralogy, major and minor oxide chemistry, and initial 87Sr/ 86Sr and <em>ε</em>Nd-<em>ε</em>Hf isotopic compositions. Ion probe U-Pb geochronology on perovskite (806 ± 22 Ma) indicates the eruption of the pipes was co-eval with plume-related magmatism within central Australia (Willouran-Gairdner Volcanic Event) associated with the opening of the Centralian Superbasin and Rodinia supercontinent break-up. The equilibration pressure and temperature of mantle-derived garnet and chromian (Cr) diopside xenocrysts range between 17 and 40 kbar and 750–1320°C and define a paleo-lithospheric thickness of 140 ± 10 km. Chemical variations of xenocrysts define litho-chemical horizons within the shallow, middle, and deep sub-continental lithospheric mantle (SCLM). The shallow SCLM (50–70 km), which includes garnet-spinel and spinel lherzolite, contains Cr diopside with weakly refertilized rare earth element compositions and unenriched compositions. The mid-lithosphere (70–85 km) has lower modal abundances of Cr diopside. This layer corresponds to a seismic mid-lithosphere discontinuity interpreted as pargasite-bearing lherzolite. The deep SCLM (&gt;90 km) comprises refertilized garnet lherzolite that was metasomatized by a silicate-carbonatite melt.</div><div><br></div><div>Geoscience Australia’s Exploring for the Future program provides precompetitive information to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. By gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge, we are building a national picture of Australia’s geology and resource potential. This leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia’s transition to net zero emissions, strong, sustainable resources and agriculture sectors, and economic opportunities and social benefits for Australia’s regional and remote communities. The Exploring for the Future program, which commenced in 2016, is an eight year, $225m investment by the Australian Government.</div><div><br></div><div><strong>Citation:</strong></div><div>Sudholz, Z. J., et al. (2023). Petrology, age, and rift origin of ultramafic lamprophyres (aillikites) at Mount Webb, a new alkaline province in Central Australia. <i>Geochemistry, Geophysics, Geosystems</i>, 24, e2023GC011120.</div><div>https://doi.org/10.1029/2023GC011120</div>

The Australian Geothermal Association compiled data on the installed capacity of direct-use geothermal and geoexchange systems in Australia, including large-scale ground source heat pumps and hot sedimentary applications through to December 2018. Large-scale direct-use hot sedimentary aquifer systems includes systems to heat swimming pools or provide hydronic heating systems. In geoexchange systems, the Earth acts as a heat source or a heat sink, exploiting the temperature difference between the surface (atmosphere) and at depth. The temperature of the Earth just a few metres below the surface is much more consistent than atmospheric temperature, especially in seasonal climates. These resources do not require the addition of geothermal heat.

3D constrained gravity inversions have been applied to gravity data in the Cooper Basin region of South Australia to delineate low density regions within the basement, beneath thick sequences of sedimentary cover. The low density regions, which are interpreted as granite bodies, may act as heat sources beneath thermally insulating sediments, thereby enhancing geothermal prospectivity. The Cooper Basin is the site of Australia's first geothermal project , where elevated crustal temperatures result from high-heat producing granites of the Big Lake Suite beneath the basin sediments. A 3D map of sediment stratigraphy was populated with densities and used to constrain the contribution of low density cover sediments to the observed gravity field. The resulting constrained density inversion model produced low density regions in the basement that coincide with local gravity lows. Further gravity inversions were generated and combined with gravity worm data to constrain the lateral and vertical extent of these discrete low density regions which we interpret as granite bodies. These Interpreted Granite Bodies (IGBs) coincide with granites intersected in wells. Analyses of a regional thermal model generated for a previous study, indicate that extra heat-production is required in the regions of the model that coincide with a number of the IGBs. Further thermal modelling was undertaken to determine the heat production differential between these high-heat producing IGBs and the surrounding basement. Two regions were identified where the high-heat producing IGBs are located beneath thick sequences of thermally insulating sediments. These regions, located to the east of the Big Lake Suite granodiorite and in the centre of the study area coinciding with the Barrolka gravity low, are considered to have high geothermal prospectivity.

<div>Australia’s Energy Commodity Resources (AECR) 2024 provides estimates of Australia’s energy commodity reserves, resources, and production as at the end of 2022. The 2024 edition of AECR also includes previously unpublished energy commodity resource estimates data compiled by Geoscience Australia for the 2022 reporting period. The AECR energy commodity resource estimates are based primarily on published open file data and aggregated (de-identified) confidential data. The annual assessment provides a baseline for the production and remaining recoverable resources of gas, oil, coal, uranium and thorium in Australia, and the global significance of our nation’s energy commodity resources. The publication also presents chapters on the status of emerging clean energy resources in Australia, including geothermal, carbon capture and storage (CCS) and hydrogen.</div>

The Virtual Geophysics Laboratory (VGL) is an environment that was developed as a data discovery and delivery facility with software and computing facilities. This design enables geoscientists to store, discover, retrieve and process datasets. Recent developments are expanding the VGL to incorporate the functionality of the Underworld software. Underworld is open source, parallel software capable of calculating the 3D temperature distribution in the crust. Numerical modelling of temperature is a tool that can be used to predict the temperature distribution at depth between and beneath measurement points based on a 3D geological map. Computing models on a regional scale tends to be computationally intensive, and high-performance computing (HPC) facilities are often required to run computations at full resolution. In order to assess uncertainty quantitatively, HPC facilities are almost always a requirement. The new developments to VGL will facilitate the discovery and access to 3D geological maps. It will also provide easier access to the Underworld software, and will provide the high performance and cloud computing facilities (hosted at the National Computing Infrastructure and elsewhere) required to run large models. The metadata associated with each run performed using VGL is automatically stored, and therefore runs completed on VGL will be repeatable and testable.