The Exploring for the Future program Showcase 2023 was held on 15-17 August 2023. Day 1 - 15th August talks included: Resourcing net zero – Dr Andrew Heap Our Geoscience Journey – Dr Karol Czarnota You can access the recording of the talks from YouTube here: <a href="https://youtu.be/uWMZBg4IK3g">2023 Showcase Day 1</a>

NDI Carrara 1 is a deep stratigraphic drill hole completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI) in collaboration with Geoscience Australia and the Northern Territory Geological Survey. It is the first test of the Carrara Sub-basin, a newly discovered Proterozoic depocentre in the South Nicholson region, based on interpretation from new seismic surveys (L210 in 2017 and L212 in 2019) acquired as part of the Exploring for the Future program. The drill hole intersected approximately 1120 m of Proterozoic sedimentary rocks unconformably overlain by 630 m of Cambrian Georgina Basin carbonates. Continuous cores recovered from 283 m to a total depth of 1751 m. Geoscience Australia conducted an extensive post-drilling analytical program that generated over 30 datasets which the interested reader can find under the EFTF webpage (under the "Data and publications" drop down menu) at https://www.eftf.ga.gov.au/south-nicholson-national-drilling-initiative This record links to the Exploring for the Future 'borehole completion report' for NDI Carrara 1 and access to all on-site downhole geophysical datasets.

As part of Geoscience Australia’s Exploring for the Future program, this study aims to analyse the hydrocarbon prospectivity in the Carrra Sub-basin through wireline log interpretation and shale gas reservoir characterisation. NDI Carrara 1 is the first stratigraphic test of the Carrara Sub-basin, a recently uncovered depocentre located within the South Nicholson region of the eastern Northern Territory and northwestern Queensland. Four chemostratigraphic packages were defined according to the informal sub-division of stratigraphy and inorganic geochemical properties. Wireline log interpretation has been conducted to derive the clay mineral compositions, porosity, gas saturation and gas contents for the unconventional shale gas reservoirs in the Proterozoic succession in NDI Carrara 1. The predominant clay minerals include illite/muscovite, mixed-layer clay, smectite, kaolinite, and minor contents of glauconite and chlorite. The average geothermal gradient is estimated to be 35.04 °C/km with a surface temperature of 29.4 °C. The average formation pressure gradient is calculated to be < 10.7 MPa/km from mud weight records. Artificial neural network technology is used to interpret the TOC content from wireline logs for unconventional shale gas reservoirs. TOC content is positively correlated with methane and ethane concentrations in mudlog gas profiles, shale porosity, formation resistivity and gas content for NDI Carrara 1. The organic-rich shales in P2 have favourable adsorbed, free and total gas contents. The organic-rich micrites within P3 have the potential in adsorbed gas, but with very low average gas saturation (< 0.01 m3/m3). Our interpretation has identified potential shale gas reservoirs, as well as tight non-organic-rich shales and siltstones with potential as gas reservoirs. These occur throughout several of the identified chemostratigraphic packages within the Proterozoic section of NDI Carrara 1.

Geoscience Australia’s Exploring for the Future (EFTF) 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 a low emissions economy, strong 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. The deep stratigraphic drill hole, NDI Carrara 1 (~1751 m), was completed in December 2020 as part of the MinEx CRC National Drilling Initiative (NDI) in collaboration with Geoscience Australia and the Northern Territory Geological Survey. It is the first test of the Carrara Sub-basin, a depocentre newly discovered in the South Nicholson region based on interpretation from seismic surveys (L210 in 2017 and L212 in 2019) recently acquired as part of the Exploring for the Future program. The drill hole intersected approximately 1100 m of Proterozoic sedimentary rocks uncomformably overlain by 630 m of Cambrian Georgina Basin carbonates. This contractor report (FIT - Schlumberger) presents hydrocarbon and aqueous fluid inclusion petrology and data (micro-thermometry, salinities etc.) on four hydrocarbon-bearing calcite veins sampled from NDI Carrara 1 between 762.56-763.60 m depth, (under contract to, and fully funded by, Geoscience Australia as part of the Exploring for the Future program).

<div>New SHRIMP U-Pb detrital zircon geochronology on Mesoproterozoic and Paleoproterozoic siliciclastic rocks from the South Nicholson region, in concert with recently acquired complementary regional geophysical datasets, has enabled comprehensive revision of the regional Proterozoic tectono-stratigraphy. The identification of analogous detrital zircon spectra between units deposited in half-graben hanging walls of major ENE-WSW trending extensional faults, the Benmara, Bauhinia, and Maloney-Mitchiebo faults, offers compelling evidence for regional tectono-stratigraphic correlation. Units sampled from the hanging walls of these faults are characterised by immature proximal lithofacies and host a small yet persistent population of <em>ca</em> 1640–1650 Ma aged zircon and lack Mesoproterozoic detritus, consistent with deposition coincident with extension during the River Extension event at <em>ca</em> 1640 Ma, an event previously identified from the Lawn Hill Platform in western Queensland. This finding suggests the hanging wall sequences are chrono-stratigraphically equivalent to the highly prospective sedimentary rocks of the Isa Superbasin, host to world-class sediment-hosted base metal deposits across western Queensland and north-eastern Northern Territory. Subsequent inversion of the extensional faults, resulted in development of south-verging thrusts, and exhumation of late Paleoproterozoic hanging wall siliciclastic rocks through overlying Mesoproterozoic South Nicholson Group rocks as fault propagated roll-over anticlines. These geochronology data and interpretations necessitate revision of the stratigraphy and the renaming of a number of stratigraphic units in the South Nicholson region. Accordingly, the distribution of the highly prospective late Paleoproterozoic units of the McArthur Basin, Lawn Hill Platform and Mount Isa Province is greatly expanded across the South Nicholson region. These findings imply that the previously underexplored South Nicholson region is a highly prospective greenfield for energy and mineral resources.</div> <b>Citation:</b> C. J. Carson, N. Kositcin, J. R. Anderson & P. A. Henson (2023) A revised Proterozoic tectono-stratigraphy of the South Nicholson region, Northern Territory, Australia—insights from SHRIMP U–Pb detrital zircon geochronology, <i>Australian Journal of Earth Sciences,</i> DOI: 10.1080/08120099.2023.2264355

<div>Strontium isotopes (87Sr/86Sr) are useful in the earth sciences (e.g. recognising geological provinces, studying geological processes) as well as in archaeological (e.g. informing on past human migrations), palaeontological/ecological (e.g. investigating extinct and extant taxa’s dietary range and migrations) and forensic (e.g. validating the origin of drinks and foodstuffs) sciences. Recently, Geoscience Australia and the University of Wollongong have teamed up to determine 87Sr/86Sr ratios in fluvial sediments selected mostly from the low-density National Geochemical Survey of Australia (NGSA; www.ga.gov.au/ngsa). Three regional projects were focussed on: inland southeastern, northern, and southwestern Australia, together covering over 2.5 million km2 of catchment area. Whilst results on <em>total</em> Sr isotopic analyses have been reported previously (Caritat et al. 2022, 2023, 2024), a pilot study targeting the isotopic composition of <em>bioavailable</em> (or labile) Sr was conducted in parallel and this dataset is released here. In contrast to the total Sr isotope analyses, which were conducted mostly on NGSA Bottom Outlet Sediments (BOS; taken on average from ~60-80 cm depth), the bioavailable Sr work used Top Outlet Sediments (TOS; taken from 0-10 cm depth) to make the results more relevant to soil-, plant- and animal-focused applications. Approximately 1 g of air-dried, coarse-sieved (<2 mm) soil sample was reacted with 2.5 M ammonium acetate (buffered to pH 7) for 24 hr on a mixing table, to extract operationally defined plant-available cations (after Stewart et al. 1998). The solution was filtered at 0.45 µm and dried down to incipient dryness. The residue was re-dissolved in 2M nitric acid. The Sr was separated by chromatography and its 87Sr/86Sr ratio determined by multicollector-inductively coupled plasma-mass spectrometry. Results for 278 samples across all three regions demonstrate a wide range of bioavailable Sr isotopic values (0.7050 to 0.7812, median 0.7191) across Australia, reflecting a large diversity of source rock lithologies, geological, pedogenic and biogeochemical processes, and, ultimately, bedrock ages. Modelling and interpretation of this dataset will be presented elsewhere. The resulting bioavailable Sr isoscape for Australia, although sparse at the moment, and models to be derived therefrom, may have applications in archaeological, paleontological and ecological studies that aim to investigate past and modern animal (including humans) dietary habits and migrations.&nbsp;The new spatial dataset is publicly available through the Geoscience Australia portal (https://portal.ga.gov.au/).</div><div><br></div><div>References cited</div><div>Caritat, P. de, Dosseto, A., Dux, F., 2022. A strontium isoscape of inland southeastern Australia, Earth System Science Data, 14, 4271–4286, https://doi.org/10.5194/essd-14-4271-2022 </div><div>Caritat, P. de, Dosseto, A., Dux, F., 2023. A strontium isoscape of northern Australia, Earth System Science Data, 15, 1655–1673, https://doi.org/10.5194/essd-15-1655-2023 </div><div>Caritat, P. de, Dosseto, A., Dux, F., 2024. A strontium isoscape of southwestern Australia and progress toward a national strontium isoscape, Earth System Science Data Discussion [non peer-reviewed preprint], https://doi.org/10.5194/essd-2024-352 </div><div>Stewart, B. W., Capo, R. C., Chadwick, O. A., 1998. Quantitative strontium isotope models for weathering, pedogenesis and biogeochemical cycling, Geoderma, 82, 173–195, https://doi.org/10.1016/S0016-7061(97)00101-8 </div>

The fundamental geological framework of the concealed Paleoproterozoic East Tennant area of northern Australia is very poorly understood, despite its relatively thin veneer of Phanerozoic cover and its position along strike from significant Au–Cu–Bi mineralisation of the Tennant Creek mining district within the outcropping Warramunga Province. We present 18 new U–Pb dates, obtained via Sensitive High Resolution Ion Micro Probe (SHRIMP), constraining the geological evolution of predominantly Paleoproterozoic metasedimentary and igneous rocks intersected by 10 stratigraphic holes drilled in the East Tennant area. The oldest rocks identified in the East Tennant area are two metasedimentary units with maximum depositional ages of ca. 1970 Ma and ca. 1895 Ma respectively, plus ca. 1870 Ma metagranitic gneiss. These units, which are unknown in the nearby Murphy Province and outcropping Warramunga Province, underlie widespread metasedimentary rocks of the Alroy Formation, which yield maximum depositional ages of 1873–1864 Ma. While parts of this unit appear to be correlative with the ca. 1860 Ma Warramunga Formation of the Warramunga Province, our data suggest that the bulk of the Alroy Formation in the East Tennant area is slightly older, reflecting widespread sedimentation at ca. 1870 Ma. Throughout the East Tennant area, the Alroy Formation was intruded by voluminous 1854–1845 Ma granites, contemporaneous with similar felsic magmatism in the outcropping Warramunga Province (Tennant Creek Supersuite) and Murphy Province (Nicholson Granite Complex). In contrast with the outcropping Warramunga Province, supracrustal rocks equivalent to the 1845–1810 Ma Ooradidgee Group are rare in the East Tennant area. Detrital zircon data from younger sedimentary successions corroborate seismic evidence that at least some of the thick sedimentary sequences intersected along the southern margin of the recently defined Brunette Downs rift corridor are possible age equivalents of the ca. 1670–1600 Ma Isa Superbasin. Our new results strengthen ca. 1870–1860 Ma stratigraphic and ca. 1850 Ma tectono-magmatic affinities between the East Tennant area, the Murphy Province, and the mineralised Warramunga Province around Tennant Creek, with important implications for mineral prospectivity of the East Tennant area. Appeared in Precambrian Research Volume 383, December 2022.

<div>Strontium isotopes (87Sr/86Sr) are useful in the earth sciences (e.g. recognising geological provinces, studying geological processes) as well in archaeological (e.g. informing on past human migrations), palaeontological/ecological (e.g. investigating extinct and extant taxa’s dietary range and migrations) and forensic (e.g. validating the origin of drinks and foodstuffs) sciences. Recently, Geoscience Australia and the University of Wollongong have teamed up to determine 87Sr/86Sr ratios in fluvial sediments selected mostly from the low-density National Geochemical Survey of Australia (www.ga.gov.au/ngsa), with a few additional Northern Australia Geochemical Survey infill samples. The present study targeted the northern parts of Western Australia, the Northern Territory and Queensland in Australia, north of 21.5 °S. The samples were taken mostly from a depth of ~60-80 cm depth in floodplain deposits at or near the outlet of large catchments (drainage basins). A coarse grain-size fraction (&lt;2 mm) was air-dried, sieved, milled then digested (hydrofluoric acid + nitric acid followed by aqua regia) to release total strontium. Preliminary results demonstrate a wide range of strontium isotopic values (0.7048 &lt; 87Sr/86Sr &lt; 1.0330) over the survey area, reflecting a large diversity of source rock lithologies, geological processes and bedrock ages. Spatial distribution of 87Sr/86Sr shows coherent (multi-point anomalies and smooth gradients), large-scale (&gt;100 km) patterns that appears to be consistent, in many places, with surface geology, regolith/soil type and/or nearby outcropping bedrock. For instance, the extensive black clay soils of the Barkly Tableland define a &gt;500 km-long northwest-southeast-trending low anomaly (87Sr/86Sr &lt; 0.7182). Where carbonate or mafic igneous rocks dominate, a low to moderate strontium isotope signature is observed. In proximity to the outcropping Proterozoic metamorphic provinces of the Tennant, McArthur, Murphy and Mount Isa geological regions, conversely, high 87Sr/86Sr values (&gt; 0.7655) are observed. A potential link between mineralisation and elevated 87Sr/86Sr values in these regions needs to be investigated in greater detail. Our results to-date indicate that incorporating soil/regolith strontium isotopes in regional, exploratory geoscience investigations can help identify basement rock types under (shallow) cover, constrain surface processes (e.g. weathering, dispersion), and, potentially, recognise components of mineral systems. Furthermore, the resulting strontium isoscape and model derived therefrom can also be utilised in archaeological, paleontological and ecological studies that aim to investigate past and modern animal (including humans) dietary habits and migrations. &nbsp;The new spatial dataset is publicly available through the Geoscience Australia portal https://portal.ga.gov.au/.</div>

NDI Carrara 1 is a deep stratigraphic drill hole (~1751m) completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI) in collaboration with Geoscience Australia and the Northern Territory Geological Survey. It is the first test of the Carrara Sub-basin, a depocentre newly discovered in the South Nicholson region based on interpretation from seismic surveys (L210 in 2017 and L212 in 2019) recently acquired as part of the Exploring for the Future program. The drill hole intersected approximately 1100 m of Proterozoic sedimentary rocks uncomformably overlain by 630 m of Cambrian Georgina Basin carbonates. This report presents petrology and clay speciation XRD conducted on of 6 selected volcaniclastic rocks taken from NDI Carrara 1 between ca. 1579 m and ca. 1653 m depth. Petrology and XRD was undertaken by Microanalysis Australia (under contract to Geoscience Australia as part of the Exploring for the Future program). Borehole completion report can be found at https://portal.ga.gov.au/bhcr/minerals/648482

A comprehensive geochemical program was carried out on rock samples collected in the NDI Carrara 1 drill hole, the first stratigraphic test of the newly discovered Carrara Sub-basin located in the South Nicholson region of northern Australia. The drill hole recovered continuous core from 284 m to total depth at 1750 m and intersected approximately 1120 m of Proterozoic sedimentary rocks, unconformably overlain by 630 m of Cambrian Georgina Basin carbonate-rich rocks. Total organic carbon (TOC) contents from Rock-Eval pyrolysis highlight the potential for several thick black shales to be a source of petroleum for conventional and unconventional plays. Cambrian rocks contain an organic-rich section with TOC contents of up to 4.7 wt.% and excellent oil-generating potential. The Proterozoic section is overmature for oil generation but mature for gas generation, with potential for generating gas in carbonaceous mudstones showing TOC contents up to 5.5 wt.% between 680 and 725 m depth. A sustained release of methane (up to 2%) recorded during drilling from 1150 to 1500 m suggests potential for an unconventional gas system in the Proterozoic rocks from 950 to 1415 m depth, which exhibit favourable organic richness and thermal maturity. The Proterozoic rocks, which are comparable in age to the sediment-hosted deposits of the Century Mine, contain local occurrences of lead, zinc and copper sulfide minerals providing hints of mineralisation. The combined geochemical results offer the promise of a potential new resource province in northern Australia. <b>Citation:</b> E. Grosjean, A.J.M. Jarrett, C.J. Boreham, L. Wang, L. Johnson, J.M. Hope, P. Ranasinghe, J.J. Brocks, A.H.E. Bailey, G.A. Butcher, C.J. Carson, Resource potential of the Proterozoic–Paleozoic Carrara depocentre, South Nicholson region, Australia: Insights from stratigraphic drilling, <i>Organic Geochemistry</i>, Volume 186, 2023, 104688, ISSN 0146-6380, DOI: https://doi.org/10.1016/j.orggeochem.2023.104688.