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.

<div>The Exploring for the Future program (EFTF) is a $225M Federal Government-funded initiative spanning the period July 2016 to June 2024. This multi-disciplinary program involves aspects of method development and new pre-competitive data acquisition at a variety of scales, with the aim of building an integrated understanding of Australia’s mineral, energy and groundwater potential. Significant work has been undertaken across northern Australia within regional-scale projects and as part of national-scale data acquisition and mapping activities. Some of these activities have been largely completed, and have generated new data and products, while others are ongoing. A comprehensive overview of the EFTF program can be found via the program website (eftf.ga.gov.au). Here, we overview a range of activities with implications for resource exploration in the Northern Territory.</div><div><br></div>This Abstract was submitted & presented to the 2023 Annual Geoscience Exploration Seminar (AGES), Alice Springs (https://industry.nt.gov.au/news/2022/december/registrations-open-for-ages-2023)

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 the petrology conducted on 50 selected thin sections of NDI Carrara 1 undertaken by Microanalysis Australia (under contract to Geoscience Australia as part of the Exploring for the Future program).

This Record presents new Sensitive High Resolution Ion Micro Probe (SHRIMP) in situ monazite U–Pb geochronological results from the East Tennant area that were obtained in March 2022 as part of Geoscience Australia’s (GA) Exploring for the Future (EFTF) program. Three samples were targeted for monazite geochronology in order to constrain the timing of metamorphism and ductile deformation in the East Tennant area. Monazites in cordierite schist from the Alroy Formation in drill hole NDIBK01 (NDIBK01.300) yielded a weighted mean 207Pb/206Pb age of 1843.6 ± 6.1 Ma (95% confidence). Paragneiss from the Alroy Formation in drill hole NDIBK10 (NDIBK10.009) yielded monazites that returned a weighted mean 207Pb/206Pb crystallisation age of 1843.5 ± 5.1 Ma. Sparse monazites in sample NDIBK04.300, a garnet phyllite from drill hole NDIBK04, yielded a weighted mean 207Pb/206Pb crystallisation age of 1831 ± 28 Ma. These ages, from samples distributed throughout the East Tennant area, are interpreted to constrain the timing of an episode of low pressure, medium-grade metamorphism and coeval deformation.

As part of Geoscience Australia's Exploring for the Future program, the East Tennant region, which is centred on the Barkly Roadhouse in the Northern Territory, was identified as having favourable geological and geophysical indicators of mineral systems potential. Potentially prospective stratigraphy in the East Tennant region is completely concealed beneath Mesoproterozoic to Quaternary cover sequences. Prior to 2020 basement rocks in the East Tennant region were only known from a handful of legacy boreholes, supported by geophysical interpretation. In order to test geophysical interpretations and obtain additional samples of basement rocks for detailed analysis, a stratigraphic drilling campaign was undertaken in the East Tennant region as part of the MinEx CRC’s National Drilling Initiative. Ten stratigraphic boreholes were drilled through the cover sequences and into basement for a total of nearly 4000 m, including over 1500 m of diamond cored basement rocks to be used for scientific purposes. Inorganic geochemical samples from East Tennant National Drilling Initiative boreholes were taken to characterise cover and basement rocks intersected during drilling. Two sampling approaches were implemented based on the rocks intersected: 1) Borehole NDIBK04 contained localised sulphide mineralisation and elevated concentrations of several economically-significant elements in portable X-ray fluorescence data. In order to understand the geochemical variability and distribution of elements important for mineral system characterisation, the entire basement interval was sampled at nominal one metre intervals. This spacing was reduced to between 0.5 and 0.25 m from 237 m to 263 m to better understand a more intense zone of mineralisation, and 2) Samples from boreholes NDIBK01, NDIBK02, NDIBK03, NDIBK05, NDIBK06, NDIBK07, NDIBK08, NDIBK09 and NDIBK10 were selected to capture lithological and geochemical variability to establish bulk rock geochemical compositions for further interpretation. Attempts were made to sample representative, lithologically consistent intervals. A total of 402 samples were selected for analysis. Sample preparation was completed at Geoscience Australia and Bureau Veritas, with all analyses performed by Bureau Veritas in Perth. All samples were submitted for X-ray fluorescence (XRF), laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), FeO determination, and loss on ignition (LOI). Samples from borehole NDIBK04 also underwent total combustion C and S, and Pb collection fire assay by ICP-MS for determination of Au, Pt and Pd concentrations. This data release presents inorganic geochemistry data acquired on rock samples from the ten East Tennant National Drilling Initiative boreholes.

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.

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 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. A comprehensive geochemical program designed to provide information about the region’s resource potential was carried out on samples collected at up to 4 meter intervals. This report presents data from magnetic susceptibility analyses undertaken by Geoscience Australia on selected rock samples to establish their ability to be magnetised in an applied external magnetic field.

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 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. A comprehensive geochemical program designed to provide information about the region’s resource potential was carried out on samples collected at up to 4 meter intervals. This report presents part 1 of the data from Rock-Eval pyrolysis analyses undertaken by Geoscience Australia on selected rock samples to establish their total organic carbon content, hydrocarbon-generating potential and thermal maturity.

<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>

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.