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 quantitative X-ray diffraction data undertaken by Geoscience Australia on selected rock samples, collected at roughly 4 m intervals.

Exploring for the Future (EFTF) is an Australian Government program led by Geoscience Australia, in partnership with state and Northern Territory governments. The first phase of the EFTF program (2016-2020) aimed to drive industry investment in resource exploration in frontier regions of northern Australia by providing new precompetitive data and information about their energy, mineral and groundwater resource potential (Carr et al 2018). The South Nicholson Basin and immediate surrounding region is situated between Paleo-Mesoproterozoic Mount Isa Province and McArthur Basin. Both the Mount Isa Province and McArthur Basin are well studied. By contrast, the adjacent South Nicholson region is less studied, and contains rocks that are mostly undercover, for which the basin evolution and resource potential is not well understood. To address this gap, the L210 South Nicholson Deep Crustal Seismic Survey was collected in 2017 in the region between the southern McArthur Basin to the Mount Isa western succession, crossing the South Nicholson Basin and Murphy Province, providing a fundamental data link across these regions (L210 South Nicholson Deep Crustal Seismic Reflection Survey). The primary aim of the survey was to investigate areas with a low measured gravity response in the region to determine whether they represent thick basin sequences, as is the case for the nearby prospective Beetaloo Sub-basin. The interpretation of this survey led to the discovery of a new basin, the Carrara Sub-basin, coinciding with a gravity low in the south-eastern South Nicholson Basin Region. This data set contains an exported set of XYZ points from interpreted horizons (Carr et al 2019) on the South Nicholson Seismic Survey (L210) in both two way time (TWT ms on PreSTM_17ga lines) and depth (m) re-interpreted on depth indexed PreSDM_17GA lines. The coordinate reference system for this dataset is WGS 1984 Australian Centre for Remote Sensing Lambert. Seismic reference datum is 350 m. The seismic reference datum are described in the EBCDIC headers of the SEGY files for each of the survey lines. Carr, L.K., Southby, C., Henson, P., Costello, R., Anderson, J.R., Jarrett, A.J M., Carson, C.J., Gorton, J., Hutton, L.J., Troup, A., Williams, B., Khider, K., Bailey, A. & Fomin, T. 2019. Exploring for the Future: South Nicholson Basin geological summary and seismic interpretation. Record 2019/21, Geoscience Australia, Canberra. http://dx.doi.org/10.11636/Record.2019.021 Carr, L.K., Southby, C., Henson, P., Anderson, J.R., Costelloe, R., Jarrett, A.J.M., Carson, C.J., MacFarlane, S.K., Gorton, J., Hutton, L., Troup, A, Williams, B., Khider, K., Bailey, A.H.E., Fomin, T. 2020. South Nicholson Basin seismic interpretation. Geoscience Australia, Canberra. http://dx.doi.org/10.11636/132029 L210 South Nicholson Deep Crustal Seismic Reflection Survey, NT and QLD, 2017. Geoscience Australia, Canberra. https://pid.geoscience.gov.au/dataset/ga/116881.

<div>Geoscience Australia’s Onshore Basin Inventories project delivers a single point of reference and creates a standardised national basin inventory that provides a whole-of-basin catalogue of geology, petroleum systems, exploration status and data coverage of hydrocarbon-prone onshore Australian sedimentary basins. In addition to summarising the current state of knowledge within each basin, the onshore basin inventory reports identify critical science questions and key exploration uncertainties that may help inform future work program planning and decision making for both government and industry. Volume 1 of the inventory covers the McArthur, South Nicholson, Georgina, Wiso, Amadeus, Warburton, Cooper and Galilee basins and Volume 2 expands this list to include the Officer, Perth and onshore Canning basins. Under Geoscience Australia’s Exploring for the Future (EFTF) program, several new onshore basin inventory reports are being delivered. Upcoming releases include the Adavale Basin of southern Queensland, and a compilation report addressing Australia’s poorly understood Mesoproterozoic basins. These are supported by value-add products that address identified data gaps and evolve regional understanding of basin evolution and prospectivity, including petroleum systems modelling, seismic reprocessing and regional geochemical studies. The Onshore Basin Inventories project continues to provide scientific and strategic direction for pre-competitive data acquisition under the EFTF work program, guiding program planning and shaping post-acquisition analysis programs.</div>

<div>This study was commissioned by Geoscience Australia (GA) to produce a report on seal capacity of select samples from the deep stratigraphic hole NDI Carrara 1, located in the Proterozoic Carrara Sub-basin in the Northern Territory. Plugs were taken from depths of interest and analysed via mercury injection capillary pressure testing. Results were provided as two reports, Part A and Part B and demonstrate that the analysed samples are capable of sealing very large columns of both methane and carbon dioxide.</div>

The first phase of the Australian Government's Exploring for the Future (EFTF) was a multi-year (2016-2020) $100.5 million initiative to increase northern Australia's desirability as a destination for industry investment to stimulate ‘greenfield’ resource exploration. In order to support this fundamental objective of the EFTF program, Geoscience Australia conducted acquisition of a diverse range of new precompetitive datasets across northern Australia, focussing on regions of unrecognised mineral, energy and groundwater resource potential. The Barkly 2D Deep Crustal Reflection Seismic Survey (L212) was acquired in 2019 as a major objective of the EFTF program in partnership with, and co-funded by, the NT Government under the Resourcing the Territory initiative. The Barkly Seismic Survey extends from the newly discovered Carrara Sub-basin in the South Nicholson Basin region to the south-eastern margins of the Beetaloo Sub-basin (Fomin, T., et al. 2019). The Barkly Seismic Survey images interpreted Paleoproterozoic to Mesoproterozoic successions extending from the Carrara Sub-basin to the highly prospective Beetaloo Sub-basin of the McArthur Basin. These successions are concealed by a persistent cover of up to 600 m of Paleozoic Georgina Basin sediments. Interpretation of the Barkly Seismic Survey established three informal geological domains, each defined by structural elements and/or basin characteristics (Southby et al, 2021). This data set contains an exported set of XYZ points from interpreted horizons (Southby et al 2022,) on the Barkly Seismic Survey (L212) in both two way time (TWT ms on PreSTM_19ga lines) and depth (m) re-interpreted on depth indexed PreSDM_19GA lines. The coordinate reference system for this dataset is WGS 1984 Australian Centre for Remote Sensing Lambert. Seismic reference datum is 350 m. The seismic reference datum are described in the EBCDIC headers of the SEGY files for each of the survey lines. Fomin, T., Costelloe, R.D., Holzschuh, J. 2019. L212 Barkly 2D Seismic Survey. Geoscience Australia, Canberra. https://pid.geoscience.gov.au/dataset/ga/132890 Southby, C., Rollet, N., Carson, C., Carr, L., Henson, P., Fomin, T., Costelloe, R., Doublier, M., Close, D. 2021. The Exploring for the Future 2019 Barkly Reflection Seismic Survey: Key discoveries and implication for resources. Geoscience Australia, Canberra. https://pid.geoscience.gov.au/dataset/ga/145107 Southby, C., Carson, C.J., Fomin, T., Rollet, N., Henson, P.A., Carr, L.K., Doublier, M.P., Close, D. 2022. Exploring for the Future - The 2019 Barkly Reflection Seismic Survey (L212). RECORD: 2022/009. Geoscience Australia, Canberra. http://dx.doi.org/10.11636/Record.2022.009

<div>NDI Carrara 1 is a deep stratigraphic borehole that was drilled in 2020 under the MinEx CRC’s National Drilling Initiative (NDI) program in collaboration with Geoscience Australia and the Northern Territory Geological Survey. NDI Carrara 1 is the first stratigraphic test of the recently described Carrara Sub-basin, a Proterozoic aged depocentre located in the South Nicholson region of northwest Queensland and the Northern Territory. The borehole was drilled to a total depth of 1751 m and penetrated a succession of Cambrian aged Georgina Basin carbonate and siliciclastic rocks that unconformably overly a thick succession of Proterozoic age siliciclastic and carbonate-rich sediments. Although drilled on the western flank of the Carrara Sub-basin, NDI Carrara 1 did not penetrate to basement. Interpretation of the L210 deep-crustal seismic survey suggests that further Proterozoic sedimentary packages known from the northern Lawn Hill Platform in northwest Queensland are likely to be found underlying the succession intersected in NDI Carrara 1. The borehole was continuously cored from 283 m to total depth, and an extensive suite of wireline logs was acquired. Geoscience Australia and partners have undertaken an extensive analytical program to understand the depositional, structural, and diagenetic history of the sediments intersected in NDI Carrara 1. This program includes a targeted geomechanical study that aims to characterise the physical properties of these Proterozoic rocks through laboratory analysis of core samples, the results of which are summarised in this data release.</div><div><br></div><div>This data release provides data from new unconfined compressive strength (UCS), single-stage triaxial testing, and laboratory ultrasonic testing for 36 sample plugs from NDI Carrara 1. These tests were performed at the CSIRO Geomechanics and Geophysics Laboratory in Perth, during January to June 2022. The full results as provided by CSIRO to Geoscience Australia are provided as an attachment to this document.&nbsp;</div>

<div>The Carrara Sub-basin, discovered in 2017 based on interpretation of 2D deep seismic surveys acquired by Geoscience Australia, is a large sedimentary depocentre in the South Nicholson region straddling the Northern Territory and Queensland. It was interpreted to contain up to 8 km of Paleoproterozoic to Cambrian rocks including stratigraphic equivalents to the Isa Superbasin, South Nicholson Group and Georgina Basin. In order to validate these stratigraphic interpretations and assess the resource prospectivity of the Carrara Sub-basin, the South Nicholson National Drilling Initiative (NDI) Carrara 1 stratigraphic drill hole was completed in late 2020 as a collaboration between the MinEx Cooperative Research Centre, Geoscience Australia and the Northern Territory Geological Survey. NDI Carrara 1 was drilled on the western flanks of the Carrara Sub-basin and reached a total depth of 1751&nbsp;m, intersecting ca. 630&nbsp;m of Cambrian Georgina Basin overlying ca. 1100&nbsp;m of Proterozoic carbonates, black shales and minor siliciclastics. More than 400 NDI Carrara&nbsp;1 physical samples were analysed as part of an extensive geochemical program, including Rock-Eval pyrolysis and compositional analyses of hydrocarbon shows, whose results and implications for energy prospectivity are summarised here.</div> This Abstract was submitted/presented to the 2022 Australian Organic Geochemistry Conference 27-29 November (https://events.csiro.au/Events/2022/October/5/Australian-Organic-Geochemistry-Conference)

<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 Barkly Seismic Survey data images a complete seismic profile from the newly discovered Carrara Sub-basin of the South Nicholson region (e.g. Carr et al 2019) to the eastern margins of the Beetaloo Sub-basin. The survey, comprising five lines and a total of 813 line kms, links into the recently acquired EFTF South Nicholson Seismic Survey (L210; Henson et al 2018, Carr et al 2019, 2020) and the Camooweal 2D seismic survey completed by the Geological Survey of Queensland in 2019. The survey has identified Paleoproterozoic to Mesoproterozoic successions extending from the Carrara Sub-basin to the highly prospective Beetaloo Sub-basin of the McArthur Basin. These successions are concealed by a persistent cover of up to 600 m of Paleozoic Georgina Basin sediments. The recent completion of the MinEx CRC deep (1751 m) stratigraphic drillhole, NDI Carrara-1, located on the western margin of the Carrara Sub-basin have greatly improved the geological constraints on our preliminary stratigraphic interpretations. Our geological interpretation (Southby et al., 2021) of the Barkly Seismic Survey established three informal geological domains, each defined by dominant structural elements and/or basin characteristics. These informal domains are, from southeast to northwest. • Carrara domain: includes the south-western margins of the Carrara Sub-basin and a shoulder of shallow metamorphic basement, where overlying Proterozoic sediments of the Carrara Sub-basin are absent. The Carrara Sub-basin is as much as 10 000 m deep (Carr et al. 2019, 2020), and interpreted to comprise four superbasin sequences from oldest to youngest, the Paleoproterozoic Leichhardt (ca. 1790–1750 Ma), Calvert (ca. 1735–1690 Ma) and Isa (ca. 1670–1575 Ma) Superbasins and the Mesoproterozoic Roper Superbasin • Brunette Downs rift corridor (BDrc) is characterised by south-easterly deepening half-grabens, controlled by steeply dipping extensional bounding faults and minor sub-parallel subsidiary faults. The rift corridor has been divided into two rift packages containing the same sedimentary sequences as in the Carrara domain. The Leichhardt Superbasin successions show stratal thickening away from the bounding fault, to the northwest, whereas the Calvert Superbasin and, in particular, the Isa Superbasin, show marked southeast-directed stratal thickening into the bounding fault. However, most importantly these features share remarkably similar orientation, geometry and structural evolution to similar half grabens identified along strike in the South Nicholson and Lawn Hill Platform regions to the north-east, representing a continuous rift corridor extending over 400 km. • Beetaloo-McArthur domain: The seismic data reveals continuation of mostly flat lying Proterozoic sedimentary successions of the Beetaloo Sub-basin (the Redbank, Glyde and Nathan packages) over some 250 km southeast towards the BDrc. The southern boundary of this domain is a fault-bounded horst of Proterozoic basement rocks interpreted to be a concealed south-west extension of Murphy Province basement and which separates the Beetaloo-McArthur domain from the BDrc. The seismic data from the Barkly Seismic Survey, in conjunction the South Nicholson survey and the ongoing work on the Carrara 1 well, has identified similarities in sedimentary successions and architecture between the Carrara Sub-basin basin and the Beetaloo Sun-basin. It has also revealed extensive Paleoproterozoic successions between the Carrara and Beetaloo sub-basins. This work will greatly improve regional resource evaluations, and stimulate greenfield exploration across this part of northern Australia. Abstract/Poster presented at the 2022 Central Australian Basins Symposium IV (https://agentur.eventsair.com/cabsiv/)

<div>NDI Carrara 1 is a 1750 m stratigraphic drill hole completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI) in collaboration with Geoscience Australia under the Exploring for the Future program and the Northern Territory Geological Survey. It is the first stratigraphic test of the Carrara Sub-basin, a recently discovered depocentre in the South Nicholson region. The drill hole intersected Cambrian and Proterozoic sediments consisting of organic-rich black shales and a thick sequence of interbedded black shales and silty sandstones with hydrocarbon shows. A comprehensive analytical program carried out by Geoscience Australia on the recovered core samples from 283 m to total depth at 1751&nbsp;m provides critical data for calibration of burial and thermal history modelling.</div><div>Using data from this drilling campaign, burial and thermal history modelling was undertaken to provide an estimate of the time-temperature maxima that the sub-basin has experienced, contributing to an understanding of hydrocarbon maturity. Proxy kerogen kinetics are assessed to estimate the petroleum prospectivity of the sub-basin and attempt to understand the timing and nature of hydrocarbon generation. Combined, these newly modelled data provide insights into the resource potential of this frontier Proterozoic hydrocarbon province, delivering foundational data to support explorers across the eastern Northern Territory and northwest Queensland.</div> <b>Citation:</b> Palu Tehani J., Grosjean Emmanuelle, Wang Liuqi, Boreham Christopher J., Bailey Adam H. E. (2023) Thermal history of the Carrara Sub-basin: insights from modelling of the NDI Carrara 1 drill hole. <i>The APPEA Journal</i><b> 63</b>, S263-S268. https://doi.org/10.1071/AJ22048