This report presents key results from hydrogeological investigations at Alice Springs, completed 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. The Southern Stuart Corridor (SSC) project area within the Northern Territory extends in a north–south corridor from Tennant Creek to Alice Springs, encompassing four water control districts and a number of remote communities. Water allocation planning and agricultural expansion in the SSC is currently limited by a paucity of data and information regarding the volume and extent of groundwater resources and groundwater systems more generally. This includes recharge rates, surface water –groundwater connectivity, and the dependency of ecosystems on groundwater. Outside the proposed agricultural areas, the project includes numerous remote communities where there is a need to secure water supplies. Geoscience Australia, in partnership with the Northern Territory Department of Environment and Natural Resources and the Power and Water Corporation, undertook an extensive program of hydrogeological investigations between 2017 and 2019. Data acquisition included helicopter airborne electromagnetic (AEM) and magnetic data, investigative groundwater bore drilling, ground-based and downhole geophysical data (including nuclear magnetic resonance for mapping water content and induction conductivity/gamma for defining geological formations), and hydrochemistry for characterising groundwater systems. This report investigates the hydrogeology across the Alice Springs focus area, which includes the Roe Creek and proposed Rocky Hill borefields, where five hydrostratigraphic units were mapped based on AEM interpretation and borehole geophysical information. The mapping supports the presence of a syncline, with a gentle parabolic fold axis that plunges westward, and demonstrates that the main Siluro-Devonian Mereenie Sandstone and Ordovician Pacoota Sandstone aquifers are continuous from Roe Creek borefield to the Rocky Hill area. Areas with the highest potential for recharge to the Paleozoic strata are where Roe Creek or the Todd River directly overlie shallow subcrop of the aquifer units. Three potential recharge areas are identified: (1) Roe Creek borefield, (2) a 3 km stretch of Roe Creek immediately west of the proposed Rocky Hill borefield, and (3) the viticulture block to the east of Rocky Hill. Analysis of groundwater chemistry and regional hydrology suggests that the rainfall threshold for recharge of the Paleozoic aquifers is ~125 mm/month, and groundwater isotope data indicate that recharge occurs rapidly. The groundwaters have similar major ion chemistry, reflecting similar geology and suggesting that all of the Paleozoic aquifers in the focus area are connected to some degree. Groundwater extraction at Roe Creek borefield since the 1960s has led to the development of a cone of depression and a groundwater divide, which has gradually moved eastward and is now east of the proposed Rocky Hill borefield. The majority of the groundwater within the focus area is of good quality, with <1000 mg/L total dissolved salts (TDS). The brackish water (7000 mg/L TDS) further to the east of the proposed Rocky Hill borefield warrants further investigation to determine the potential risk of it being captured by the cone of depression following the development of this borefield. This study provides new insight to the hydrogeological understanding of the Alice Springs focus area. Specifically, this investigation demonstrates that the Roe Creek and proposed Rocky Hill borefields, and a nearby viticulture area are all extracting from the same aquifer system. This finding will inform the future management and security of the Alice Springs community water supply. New groundwater resource estimates and a water level monitoring scheme can be developed to support the management of this vital groundwater resource.

This resource includes backscatter data for Arafura Marine Park (Arafura Sea) collected by Geoscience Australia (GA) and the Australian Institute of Marine Science during the period 2 – 15 November 2020 on the RV Solander. The survey was undertaken as a collaborative project funded through the National Environmental Science Program Marine Biodiversity Hub, with co-investment by GA and AIMS. The purpose of the project was to build baseline information for benthic habitats in Arafura Marine Park that will support ongoing environmental monitoring within the North Marine Park Network as part of the 10-year management plan (2018-2028). Data acquisition for the project included multibeam bathymetry and backscatter for two areas (Money Shoal and Pillar Bank), seabed samples and underwater imagery of benthic communities and demersal fish. This backscatter dataset contains two 32-bit geotiff files of the backscatter mosaic for two survey areas produced from the processed EM2040C Dual Head system using the CMST-GA MB Process v15.04.04.0 (x64) toolbox software co-developed by the Centre for Marine Science and Technology at Curtin University and Geoscience Australia. A detailed report on the survey is provided in: Picard, K. Stowar, M., Roberts, N., Siwabessy, J., Abdul Wahab, M.A., Galaiduk, R., Miller, K., Nichol, S. 2021. Arafura Marine Park Post Survey Report. Report to the National Environmental Science Program, Marine Biodiversity Hub (https://www.nespmarine.edu.au/node/4505).

This dataset provides the locations and status, as at 30 June 2020, of Australian operating mines, mines under development, mines on care and maintenance and resource deposits associated with critical minerals. Developing mines are deposits where the project has a positive feasibility study, development has commenced or all approvals have been received. Mines under care and maintenance and resource deposits are based on known resource estimations and may produce critical minerals in the future.

These videos are recordings of online secondary teacher professional learning sessions, delivered by Geoscience Australia’s Education Team. “Can I Fall Down the Cracks?” Plate Tectonic Misconceptions Part 1 This session focused on common misconceptions that are encountered when teaching plate tectonics. The student misconceptions addressed are: 1. We can’t see the tectonic plates (starting at 5:35) 2. The mantle is made of liquid rock (starting at 11:25) 3. The plates move by convection in the mantle (starting at 17:35) 4. When plates collide one always goes under the other (starting at 22:15) 57 minutes total duration, with Q&A with an expert scientist starting at 34 minutes. “Can I Fall Down the Cracks?” Plate Tectonic Misconceptions Part 2 This session focused on common misconceptions that are encountered when teaching hazards associated with plate tectonics. The student misconceptions addressed are: 1. Earthquakes are measured using the Richter scale (starting at 3:15) 2. The magnitude of an earthquake depends on how far away it is (starting at 7:20) 3. Earthquakes can be predicted (starting at 10:52) This section includes a description of Raspberry Shake equipment: low cost earthquake monitoring for the classroom 4. There are no volcanoes in Australia (starting at 18:25) 5. You can surf a tsunami (starting at 24:17) 51 minutes total duration, with Q&A with an expert scientist starting at 37 minutes.

This Record presents 40Ar/39Ar chronologic results acquired in support of collaborative regional geoscientific investigations and mapping programs conducted by Geoscience Australia (GA) and the Northern Territory Geological Survey (NTGS). Argon isotopic data and interpretations from hornblende, muscovite, and biotite from seven samples collected from the Aileron Province in ALCOOTA , HUCKITTA, HALE RIVER, and ILLOGWA CREEK in the Northern Territory are presented herein. The results complement pre-existing geochronological constraints from U–Pb zircon and monazite analyses of the same or related samples, and provide new constraints on the thermal and deformation history of the Aileron Province. Three samples (2003082017, 2003082021, 2003083040) were taken from ALCOOTA in the northeastern portion of the Aileron Province. Biotite in sample 2003082017 from the ca 1.81 Ga Crooked Hole Granite records cooling below 320–280°C at 441 ± 5 Ma. Biotite in sample 2003082021 from the ca 1.73 Ga Jamaica Granite records cooling below 320–280°C at or after 414 ± 2 Ma. Muscovite in sample 2003083040 from the Delny Metamorphics, which were deposited after ca 1.82 Ga and preserve evidence for metamorphism at ca 1.72 Ga and 1.69 Ga, records cooling below 430–390°C at 399 ± 2 Ma. The fabrics preserved in the samples from the Crooked Hole Granite and Delny Metamorphics are interpreted to have formed due to dynamic metamorphism related to movement on the Waite River Shear Zone, an extension of the Delny Shear Zone, during the Palaeoproterozoic. Portions of the northeastern Aileron Province are unconformably overlain by the Neoproterozoic–Cambrian Georgina Basin, indicating these samples were likely at or near the surface by the Neoproterozoic. Together, these data indicate that rocks of the Aileron Province in ALCOOTA were subjected to heating above ~400°C during the Palaeozoic. Two samples (2003087859K, 2003087862F) of exoskarn from an indeterminate unit were taken from drillhole MDDH4 in the Molyhil tungsten–molybdenum deposit in central HUCKITTA. The rocks hosting the Molyhil tungsten–molybdenum deposit are interpreted as ca 1.79 Ga Deep Bore Metamorphics and ca 1.80 Ga Yam Gneiss. They experienced long-lived metamorphism during the Palaeoproterozoic, with supersolidus metamorphism observed until at least ca 1.72 Ga. Hornblende from sample 2003087859K indicates cooling below 520–480°C by 1702 ± 5 Ma and may closely approximate timing of skarn-related mineralisation at the Molyhil deposit; hornblende from sample 2003087862F records a phase of fluid flow at the Molyhil deposit at 1660 ± 4 Ma. The Salthole Gneiss has a granitic protolith that was emplaced at ca 1.79 Ga, and experienced alteration at ca 1.77 Ga. Muscovite from sample 2010080001 of Salthole Gneiss from the Illogwa Shear Zone in ILLOGWA CREEK records cooling of the sample below ~430–390°C at 327 ± 2 Ma. This may reflect the timing of movement of, or fluid flux along, the Illogwa Shear Zone. An unnamed quartzite in the Casey Inlier in HALE RIVER has a zircon U–Pb maximum depositional age of ca 1.24 Ga. Muscovite from sample HA05IRS071 of this unnamed quartzite yields an age of 1072 ± 8 Ma, which likely approximates, or closely post-dates, the timing of deformation in this sample; it provides the first direct evidence for a Mesoproterozoic episode of deformation in this part of the Aileron Province.

Geoscience Australia is Australia’s Earth science public sector organisation, recognised for its expert data capabilities and high level of expertise. As the nation’s trusted advisor on geology and geography the organisation is the premium provider of data, science and analysis for decision makers. Internally, Geoscience Australia is currently targeting and refining its core capabilities in order to establish and clearly articulate our value proposition and service offering to stakeholders.

This Record presents new U–Pb geochronological data, obtained via Sensitive High Resolution Ion Micro Probe (SHRIMP), from 43 samples of predominantly igneous rocks collected from the East Riverina region of the central Lachlan Orogen, New South Wales. The results presented herein correspond to the reporting period July 2016–June 2020. This work is part of an ongoing Geochronology Project, conducted by the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA) under a National Collaborative Framework agreement, to better understand the geological evolution and mineral prospectivity of the central Lachlan Orogen in southern NSW (Bodorkos et al., 2013; 2015; 2016, 2018; Waltenberg et al., 2019).

An assessment of tight, shale and deep coal gas prospectivity of the Cooper Basin has been undertaken as part of the Australian Government’s Geological and Bioregional Assessment Program. This aims to both encourage exploration and understand the potential impacts of resource development on water and the environment. This appendix presents a review of the regional petroleum prospectivity, its exploration, and the characterisation and analysis of shale, deep coal and tight gas in Carboniferous–Permian Gidgealpa Group of the Cooper Basin. The Cooper Basin is Australia’s premier onshore conventional hydrocarbon-producing province providing domestic gas for the East Coast Gas Market. As of December 2014, the Cooper and Eromanga basins have produced 6.54 Tcf of gas since 1969. The basins contain 256 gas fields as well as 166 oil fields that are currently in production. Gas is predominantly reservoired in the Cooper Basin, whereas the overlying Eromanga Basin hosts mainly oil. Hydrocarbon shows are found in the reservoir units throughout the succession. Recently, exploration targeting a range of unconventional plays has gained momentum. Unconventional play types within the mainly Permian Gidgealpa Group include shale gas associated with the Patchawarra Formation and the Roseneath and Murteree shales, tight and deep coal gas accumulations within the Toolachee, Epsilon and Patchawarra formations and additional tight gas plays in the Daralingie Formation and Tirrawarra Sandstone. To date, at least 80 wells have been drilled to test shale, tight and deep coal gas plays. Given the basin’s existing conventional production, and its processing and pipeline infrastructure, these plays are well placed to be rapidly commercialised, should exploration be successful. A prospectivity confidence mapping workflow was developed to evaluate the regional distribution of key unconventional gas plays within the Gidgealpa Group. For each play type, key physical properties were identified and characterised. The specific physical properties evaluated include formation extents, source rock properties (net thickness, TOC, quality and thermal maturity), reservoir characteristics (porosity, permeability, gas saturation and brittleness), regional stress regime and overpressure. Parameters for mappable physical properties were individually classified to assign prospectivity rankings. Individual properties were then multiplied together produce formation and play-specific prospectivity confidence maps. Non-mappable criteria were not integrated into the prospectivity mapping but were used to better understand the geological characteristics of the formations. Overall, both source and reservoir characteristics were found to be moderately to highly favourable for all play types assessed. Abundant source rocks are present in the Gidgealpa Group across the Cooper Basin. The Toolachee and Patchawarra formations are the richest, thickest and most extensive source rocks, with good to excellent source potential across their entire formation extents. Net shale, coal and sand thicknesses also demonstrate an abundance of potential reservoir units in the Gidgealpa Group across the basin. The predominantly fluvial Toolachee Formation is thickest in the Windorah Trough and Ullenbury Depression. Average effective porosity for assessed tight gas plays ranges from 6.7 % in the fluvio-deltaic to lacustrine Epsilon Formation to 7.8% in the Toolachee Formation. Based on an assessment of the brittleness of the shales and coaly shales, the Patchawarra Formation appears to be most favourable for hydraulic stimulation with an average Brittleness Index of 0.695, indicative of brittle rocks. This compares to the less brittle lacustrine Roseneath and Murteree shales have brittleness indices of 0.343 and 0.374, respectively. As-received total gas content is favourable, with averages ranging from 1.3 scc/g in the Patchawarra Formation to 1.6 scc/g for the Murteree Shale. The regional stress regime has an approximately east-west oriented maximum horizontal stress azimuth, resulting in predominantly strike-slip faulting to reverse faulting, depending on the depth, lithology and proximity of structures, e.g. GMI ridge. Significant overpressure is present at depths greater than 2800 m, especially in the Nappamerri and Patchawarra troughs. Overpressures are generally constrained to the Gidgealpa Group, with the Toolachee Formation being the youngest formation in which significant overpressure has been achieved. Based on a review of the geomechanical properties of the Cooper Basin sedimentary succession, it was found that stress variations within and between lithologies and formations are likely to provide natural barriers to fracture propagation between the gas saturated Permian sediments and the overlying Eromanga Basin. Prospectivity confidence maps were generated for six individual shale and deep coal plays and one combined tight gas play across the Gidgealpa Group. Comparison with key wells targeting shale, tight and deep coal gas plays, indicates that the prospectivity confidence mapping results are largely consistent with exploration activity to-date, with the highest prospectivity confidence for tight, shale and deep coal gas plays mapped in the Nappamerri, Patchawarra, Windorah, Allunga and Wooloo troughs and the southern Ullenbury Depression. Consequently, there is more confidence in the resultant maps in the southern Cooper Basin as more data was available here. Prospectivity confidence maps are relative, therefore a high prospectivity confidence does not equate to 100 % chance of success for a particular formation or play. The outputs of this regional prospectivity assessment identify areas warranting more detailed data collection and exploration and the assessment of potential impacts of resource development on water and the environment. The results also have the potential to encourage further exploration investment in underexplored regions of the Cooper Basin.

This appendix provides a regional geological analysis and conceptualisation of the Cooper GBA region. It delivers information critical for the shale, tight and deep coal gas prospectivity assessment outlined in the petroleum prospectivity technical appendix (Lech et al., 2019), and for input into assessing the potential impacts on groundwater and surface water assets detailed in the hydrogeology (Evans et al., 2019) and hydraulic fracturing (Kear et al., 2019) technical appendices. The Cooper Basin is a Carboniferous to Triassic intracratonic basin in north-eastern South Australia and south-western Queensland. It has a total area of approximately 127,000 km2, of which about three quarters lies within Queensland and the remainder lies within South Australia. Section 2 provides a comprehensive inventory and review of existing open data and information for the Cooper GBA region relevant for the prospectivity assessment (see the petroleum prospectivity technical appendix (Lech et al., 2019)) and hydrogeological characterisation (see the hydrogeology technical appendix (Evans et al., 2019)). It includes discussion of the datasets incorporated in the data inventory. A broad range of datasets were utilised to develop a three-dimensional conceptualisation of the geological basin. These include: geographic and cultural datasets which details the location and nature of administrative boundaries, infrastructure and topography; and geological datasets such as surface geology and geological provinces, well and seismic data and geophysical data. A range of public domain publications, reports and data packages for the Cooper Basin are also utilised to characterise the basin architecture and evolution. Section 3 reviews the Cooper Basin’s geological setting and the GBA region’s basin evolution from pre-Permian basement to creation of the Cooper, Eromanga and Lake Eyre basins. Section 4 reviews the main structural elements of the Cooper Basin and how these relate to the basin’s stratigraphy and evolution. The base of the Cooper Basin succession sits at depths of up to 4500 m, and reaches thicknesses in excess of 2400 m. The Cooper Basin is divided into north-eastern and south-western areas, which show different structural and sedimentary histories, and are separated by a series of north-west–south-east trending ridges. In the south-west the Cooper Basin unconformably overlies lower Paleozoic sediments of the Warburton Basin, and includes three major troughs (Patchawarra, Nappamerri and Tenappera troughs) separated by ridges (the Gidgealpa–Merrimelia–Innamincka and Murteree ridges). The depocentres include a thick succession of Permian to Triassic sediments (the Gidgealpa and Nappamerri groups) deposited in fluvio-glacial to fluvio-lacustrine and deltaic environments. The north-eastern Cooper Basin overlies Devonian sediments associated with the Adavale Basin. Here the Permian succession is thinner than in the south-west, and the major depocentres, including the Windorah Trough and Ullenbury Depression, are generally less well defined. The Cooper Basin is entirely and disconformably overlain by the Jurassic–Cretaceous Eromanga Basin. In the Cooper GBA region the Eromanga Basin includes two major depocentres, the Central Eromanga Depocentre and the Poolowanna Trough, and exceeds thicknesses of 2500 m. Deposition within the Eromanga Basin was relatively continuous and widespread and was controlled by subsidence rates and plate tectonic events along the eastern margins of the Australian Plate. The Eromanga Basin is comprised of a succession of terrestrial and marine origin. It includes a basal succession of terrestrial sedimentary rocks, followed by a middle marine succession, then finally an upper terrestrial succession. The Lake Eyre Basin is a Cenozoic sedimentary succession overlying the Eromanga Basin, covering parts of northern and eastern South Australia, south-eastern Northern Territory, western Queensland and north-western New South Wales. The Lake Eyre Basin is subdivided into sub-basins, with the northern part of the Callabonna Sub-basin overlying the Cooper Basin. Here the basin is up to 300 m thick and contains sediments deposited from the Paleocene through to the Quaternary. Deposition within the Lake Eyre Basin is recognised to have occurred in three phases, punctuated by periods of tectonic activity and deep weathering. This technical appendix provides the conceptual framework to better understand the potential connectivity between the Cooper Basin and overlying aquifers of the Great Artesian Basin and to help understand potential impacts of shale, tight and deep coal gas development on water and water-dependent assets.

Assessing the regional prospectivity of tight, shale and deep coal gas resources in the Cooper Basin is an integral component of the Australian Government’s Geological and Bioregional Assessment Program, which aims to encourage exploration and understand the potential impacts of resource development on water and the environment. The Permo-Triassic Cooper Basin is Australia’s premier onshore conventional hydrocarbon-producing province, yet is relatively underexplored for unconventional gas resources. A chance of success mapping workflow, using rapid integration of new and existing data, was developed to evaluate the regional distribution of key gas plays within the Gidgealpa Group. For each play type, key physical properties (e.g. lithology, formation depths and extents, source rock and reservoir characteristics, and rock mechanics) were identified and criteria were used to assign prospectivity rankings. Parameter maps for individual physical properties were classified, weighted and then combined into prospectivity confidence maps that represent each play’s relative chance of success. These combined maps show a high chance of success for tight, shale and deep coal gas plays in the Nappamerri, Patchawarra and Windorah troughs, largely consistent with exploration results to-date. The outputs of this regional screening process help identify additional areas warranting investigation, and may encourage further exploration investment in the basin. This methodology can be applied to other unconventional hydrocarbon plays in frontier and proven basins.