The Layered Geology of Australia web map service is a seamless national coverage of Australia’s surface and subsurface geology. Geology concealed under younger cover units are mapped by effectively removing the overlying stratigraphy (Liu et al., 2015). This dataset is a layered product and comprises five chronostratigraphic time slices: Cenozoic, Mesozoic, Paleozoic, Neoproterozoic, and Pre-Neoproterozoic. As an example, the Mesozoic time slice (or layer) shows Mesozoic age geology that would be present if all Cenozoic units were removed. The Pre-Neoproterozoic time slice shows what would be visible if all Neoproterozoic, Paleozoic, Mesozoic, and Cenozoic units were removed. The Cenozoic time slice layer for the national dataset was extracted from Raymond et al., 2012. Surface Geology of Australia, 1:1 000 000 scale, 2012 edition. Geoscience Australia, Canberra.

As global metal demands are increasing whilst new discoveries are declining, the magnetotelluric (MT) technique has shown promise as an effective technique to aid mineral systems mapping. Several case studies have shown a spatial correlation between mineral deposits and conductors, with some showing that resistivity models derived from MT are capable of mapping mineral systems from the lithosphere to deposit scale. However, until now, the statistical significance of such correlations has not been demonstrated and therefore hindered robust utilization of MT data in mineral potential assessments. Here we quantitatively analyze resistivity models from Australia, the United States of America (USA), South America and China and demonstrate that there is a statistically-significant correlation between upper mantle conductors and porphyry copper deposits, and between mid-crustal conductors and orogenic gold deposits. Volcanic hosted massive sulfide deposits show significant correlation with upper mantle conductors in Australia. Differences in the correlation pattern between these deposit types likely relate to differences in the chemistry, redox state and location of source mineralizing fluids and magmas, and indicate signatures of mineral system processes can be preserved in the crust and mantle lithosphere for hundreds of millions of years. Appeared in Scientific Reports volume 12, Article number: 8190 (2022), 17 May 2022

This North-east Australian Fractured Rock Province dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. In fractured rock aquifers, groundwater is stored in the fractures, joints, bedding planes and cavities of the rock mass. About 40 per cent of groundwater in Australia is stored in fractured rock aquifers, and much of this may be available for irrigation, town water supplies, stock watering and domestic use. Approximately 33% of all bores in Australia are in fractured systems, representing about 10 per cent of total extraction. Groundwater yield is extremely variable, and dependent on the distribution of major fractures. However, rates of groundwater movement in fractured rock systems are difficult to quantify. Characterising groundwater flow in fractured rock aquifers is difficult with existing techniques, and groundwater flow direction can be related more to the orientation of fractures than to the hydraulic head distribution. Recharge in fractured rock aquifers is usually local and intermediate. The Queensland fractured rock is taken to be that part of the northern elements of the Eastern Fracture Rock provinces that extends from the southern part of the Laura Basin, south to the state boundary with New South Wales, and inland as far as the Bundock and Galilee Basins. It comprises the Mossman, Thomson and New England Orogens, and related Provinces. These include: i) The Mossman Orogen, including the Hodgkinson Province, and the Broken River Province; ii) The Thomson Orogen, comprising Neoprotozoic – Early Paleozoic Provinces, including the Anakie Province, Barnard Province, Charters Tower Province, Greenvale Province, and Iron Range Province; and iii) The New England Orogen, including the Gympie Province, Connors-Auburn Province, Yarrol Province, Wandilla Province, Woolomin Province, Calliope Province, Marlborough Province, and Silverwood Province

The Mineral Potential web service provides access to digital datasets used in the assessment of mineral potential in Australia. The service includes maps showing the potential for sediment-hosted base metal mineral systems in Australia.

This Galilee Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. This Galilee Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The Galilee Basin is a large intracratonic sedimentary basin in central Queensland. The basin contains a variably thick sequence of Late Carboniferous to Middle Triassic clastic sedimentary rocks dominated by laterally extensive sandstone, mudstone and coal. These rocks were mostly deposited in non-marine environments (rivers, swamps and lakes), although there is minor evidence for marginal marine settings such as deltas and estuaries. Sedimentation did not occur continuously across the approximately 90 million year history of basin development, and intervals of episodic compression, uplift and erosion were marked by distinct depositional breaks. Over much of the surface area of the Galilee Basin the main aquifers targeted for groundwater extraction occur in the younger rocks and sediments that overlie the deeper sequence of the Galilee Basin. The primary aquifers that supply groundwater in this region are those of the Eromanga Basin, as well as more localised deposits of Cenozoic alluvium. However, in the central-east and north-east of the Galilee Basin, the Carboniferous to Triassic rocks occur at or close to surface and several aquifer units supply significant volumes of groundwater to support pastoral and town water supplies, as well as being the water source for several spring complexes. The three main groundwater systems identified in the Galilee Basin occur in the 1. Clematis Group aquifer, 2. partial aquifer of the upper Permian coal measures (including the Betts Creek beds and Colinlea Sandstone), and 3. aquifers of the basal Joe Joe Group. The main hydrogeological units that confine regional groundwater flow in the Galilee Basin are (from upper- to lower-most) the Moolayember Formation, Rewan Formation, Jochmus Formation and Jericho Formation. However, some bores may tap local groundwater resources within these regional aquitards in areas where they outcrop or occur close to surface. Such areas of localised partial aquifer potential may be due in part to enhanced groundwater storage due to weathering and fracturing.

As part of Geoscience Australia’s Exploring for the Future Program, Broadband and Audio Magnetotelluric (MT) data were acquired at 131 stations in the East Tennant region, Northern Territory, in 2019. This survey aimed to characterise major crustal structures, to map cover thickness to assist in stratigraphic drill targeting, and to help understand mineral potential in the region. The data package was released in December 2019 (http://dx.doi.org/10.26186/5df80d8615367) and the 3D resistivity model was released in March 2020 (https://pid.geoscience.gov.au/dataset/ga/135011). We applied a probabilistic approach to inverting high-frequency MT data for cover thickness estimation using the 1D Rj-McMCMT code, newly developed in Geoscience Australia. The inversion employs multiple Markov chains in parallel to generate an ensemble of millions of resistivity models that adequately fit the data given the assigned noise levels. The algorithm uses trans-dimensional Markov chain Monte Carlo techniques to solve for a probabilistic resistivity-depth model. Once the ensemble of models is generated, its statistics are analysed to assess the posterior probability distribution of the resistivity at any particular depth, as well as the number of layers and the depths of the interfaces. This stochastic approach gives a thorough exploration of the model space and a more robust estimation of uncertainty than deterministic methods allow. This release package includes the results of probabilistic inversion of Audio Magnetotelluric data at the 131 stations. They can be used to estimate cover thickness for drill site planning, and to map the base of geological basins in the region. Model data files are large, but can be made available on request to clientservices@ga.gov.au.

The Exploring for the Future (EFTF) Program is a multiyear, federally funded initiative to better characterise the mineral, energy and groundwater resource potential across Australia. As part of this initiative, this data record presents mineral fluid inclusion data from two sample from the South Nicholson region. The South Nicholson region straddles north-eastern Northern Territory and north-western Queensland, and prior to the EFTF program, arguably represented one of the least geologically understood regions of Proterozoic northern Australia. The South Nicholson region is situated between two highly prospective provinces, the greater McArthur Basin in the Northern Territory, the Lawn Hill Platform and the Mount Isa Province in Queensland, both with demonstrated hydrocarbon and base-metal potential. These new fluid inclusion data provide information on sedimentary and volcanic rocks in the South Nicholson region that complement other components of the EFTF program, including the South Nicholson Basin and Barkly seismic surveys, comprehensive geochronology and geochemical programs, hydrocarbon prospectivity studies and other extensive regional geophysical surveys to better understand the geological evolution and basin architecture of northern Australia. The primary objective of the program is to facilitate identification of areas of unrecognised resource potential and prospectivity and encourage and stimulate ‘greenfield’ resource exploration. This record presents new fluid inclusion data from two outcrop samples: a) siliceous hydrothermal ‘white smoker’ pipes within the ca. 1660–1630 Ma Buddycurrawa Volcanics (Benmara Group, Benmara region) and b) feeder veinlets of a manganese oxide occurrence in the Carrara Range and hosted within the late Paleoproterozoic Plain Creek Formation (McNamara Group). Both samples are from the MOUNT DRUMMOND 1:250 000 map-sheet, north-eastern Northern Territory and were collected as part of EFTF helicopter-based field operations and ground mapping during May 2018.

Lithospheric structure and composition have direct relevance for our understanding of mineral prospectivity. Aspects of the lithosphere can be imaged using geophysical inversion or analysed from exhumed samples at the surface of the Earth, but it is a challenge to ensure consistency between competing models and datasets. The LitMod platform provides a probabilistic inversion framework that uses geology as the fabric to unify multiple geophysical techniques and incorporates a priori geochemical information. Here, we present results from the first application of LitMod to the Australian continent. We demonstrate the ability to map important geophysical surfaces, and to differentiate between compositional (e.g. metasomatism) and thermal anomalies. We validate the posterior predictions from our inversion against independent studies, and this highlights the robustness of our results. Finally, we discuss recent technological advances in the implementation of LitMod3D_4INV, and how the model can be used to bring together multiple projects within the Exploring for the Future program to image the lithospheric mantle. The implications of this work extend beyond mineral prospectivity, and will ultimately inform our understanding of energy systems, groundwater and seismic hazard. <b>Citation:</b> Haynes, M.W., Fomin, I., Afonso, J.C., Gorbatov, A., Czarnota, K. and Salajegheh, F., 2020. Developing thermochemical models of Australia’s lithosphere. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

This study was commissioned by Geoscience Australia (GA) to produce a report on source rock maturity and maceral/organoclast assemblages for a suite of rock samples from from the MinEx CRC National Drilling Initiative (NDI) Carrara 1 drill hole in the Northern Territory, Australia. 25 samples consisting of 24 drill core samples and 1 drill cutting sample were studied using organic petrological methods to evaluate the organic matter type, content, thermal maturity and hydrocarbon potential. Vitrinite was absent in all the samples and variable amounts of bitumen was present throughout the stratigraphic section studied. Fluorescing lamalginite was present in the upper part of the section and no bioclasts were detected in the samples from the lower section. Vitrinite reflectance equivalents calculated from bitumen reflectance indicated that upper part of the section containing lamalginite is early to mid-mature and the lower part of the section is over-mature. Good potential for liquid hydrocarbons may exist in the upper part of the section and the overmature lower part of the stratigraphic section could be gas prone.

This report presents a summary of the groundwater and surface water hydrochemistry data release from the Daly River project conducted as part of Exploring for the Future (EFTF)—an eight year, $225 million Australian Government funded geoscience data and information acquisition program focused on better understanding the potential mineral, energy and groundwater resources across Australia. This data release records the groundwater sample collection methods and hydrochemistry and isotope data from monitoring bores in the Daly River project area, Northern Territory (NT). The Daly River project is a collaborative study between Geoscience Australia and the NT Government. Hydrochemistry and isotope data were collected from existing bores in the Daly River area. The sampling methods, quality assurance/quality control procedures, analytical methods and results are included in this report and all hydrochemistry data are available for download from the link at right.