In 2017, under the Federal Governments’ Exploring for the Future program, in collaboration with the NTGS under their ‘Resourcing the Territory’ initiative, Geoscience Australia acquired the South Nicholson Deep Crustal Seismic Reflection Survey in north-eastern Northern Territory. One of the key discoveries of this survey was the identification of a large sedimentary depocentre, concealed beneath the sedimentary rocks of the Cambrian Georgina Basin. This depocentre, up to 7 km deep, termed the ‘Carrara Sub-basin’ by Geoscience Australia (e.g. Carr et al., 2020), is interpreted to contain thick sequences of resource-rich Proterozoic rocks, broadly equivalent to rocks of the greater McArthur Basin (Northern Territory) and northern Lawn Hill Platform and Mount Isa Province of northwest Queensland, rocks that are highly prospective for sediment-hosted base metals and unconventional hydrocarbons. The Carrara-1 stratigraphic drillhole was completed in late 2020, as a collaboration between Geoscience Australia, the Northern Territory Geological Survey and the MinEx CRC. Carrara-1 is the first drillhole to intersect the undifferentiated Proterozoic rocks of the Carrara Sub-Basin. Carrara-1 is located on the western flanks of the Carrara Sub-basin on the South Nicholson Seismic line (17GA-SN1), reaching a total depth of 1751 m, intersecting ca. 630 m of Cambrian Georgina Basin overlying ca. 1100 m of Proterozoic carbonates, black shales and minor siliciclastics. These rocks preserve evidence of both oil and gas and visible disseminated sulphide mineralisation. Carrara-1 affords us a privileged glimpse into this highly prospective and exciting frontier Proterozoic basin.

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 Pb isotopes analyses conducted on 22 selected whole rock samples of NDI Carrara 1 undertaken by University of Melbourne.

To test existing geological interpretations and the regional stratigraphic relationships of the Carrara Sub-basin with adjacent resource-rich provinces, the deep stratigraphic drill hole NDI Carrara 1 was located on the western flanks of the Carrara Sub-basin, on the seismic line 17GA-SN1. The recovery of high quality near-continuous core from the Carrara Sub-basin, in concert with the spectrum of baseline analytical work being conducted by Geoscience Australia through the EFTF program, as well as other work by government and university researchers is greatly improving our understanding of this new basin. While recently published geochemistry baseline datasets have provided valuable insight into the Carrara Sub-basin, the age of the sedimentary rocks intersected by NDI Carrara 1 and their chronostratigraphic relationships with adjacent resource rich regions has remained an outstanding question. In this contribution, we present new sensitive high-resolution ion microprobe (SHRIMP) geochronology results from NDI Carrara 1 and establish regional stratigraphic correlations to better understand the energy and base-metal resource potential of this exciting frontier basin in northern Australia.

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.

<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>

Exploring for the Future (EFTF) is an ongoing multiyear initiative by the Australian Government, conducted by Geoscience Australia, in partnership with state and Northern Territory government agencies and other partner research institutes. The first phase of the EFTF program (2016-2020) aimed to improve Australia’s desirability for industry investment in resource exploration in frontier or ‘greenfield’ regions across northern Australia. As part of the program, Geoscience Australia employed a range of both established and innovative techniques to gather new precompetitive data and information to develop new insight into the energy, mineral and groundwater resource potential across northern Australia. To maximise impact and to stimulate industry exploration activity, Geoscience Australia focussed activities in greenfield areas where understanding of resource potential was limited. In order to address this overarching objective under the EFTF program, Geoscience Australia led acquisition of two deep crustal reflection seismic surveys in the South Nicholson region, an understudied area of little previous seismic data, straddling north-eastern Northern Territory and north-western Queensland. The first survey, L210 South Nicholson 2D Deep Crustal Seismic Survey acquired in 2017, consisted of five overlapping seismic lines (17GA-SN1 to SN5), totalling ~1100 line-km. Survey L210 linked directly into legacy Geoscience Australia seismic lines (06GA-M1 and 06GA-M2) in the vicinity of the world-class Pb-Zn Century Mine in Queensland. The results from survey L210 profoundly revised our geological understanding of the South Nicholson region, and led to the key discovery of an extensive sag basin, the Carrara Sub-basin, containing highly prospective late Paleoproterozoic to Mesoproterozoic rocks with strong affinities with the adjacent Mount Isa Province and Lawn Hill Platform. To complement and expand on the outstanding success of the South Nicholson survey and to continue to explore the resource potential across the underexplored and mostly undercover South Nicholson and Barkly regions, a second seismic survey was acquired in late 2019, the Barkly 2D reflection survey (L212). The Barkly seismic survey comprises five intersecting lines (19GA-B1 to B5), totalling ~813 line-km, extending from the NT-QLD border in the south-east, near Camooweal, to the highly prospective Beetaloo Sub-basin in the north-west. The survey ties into the South Nicholson survey (L210), the recently acquired Camooweal 2D reflection seismic survey by the Geological Survey of Queensland and industry 2D seismic in the Beetaloo Sub-basin, leveraging on and maximising the scientific value and impact on all surveys. The Barkly reflection seismic data images the south-western margin of the Carrara Sub-basin and identified additional previously unrecognised, structurally-disrupted basins of Proterozoic strata, bounded by broadly northeast trending basement highs. Critically, the survey demonstrates the stratigraphic continuity of highly prospective Proterozoic strata from the Beetaloo Sub-basin into these newly discovered, but as yet unevaluated, concealed basins and into the Carrara Sub-basin, further attesting to the regions outstanding potential for mineral and hydrocarbon resources. This survey, in concert with the South Nicholson seismic survey and other complementary EFTF funded regional geochemical, geochronology and geophysical data acquisition surveys, significantly improves our understanding of the geological evolution, basin architecture and the resource potential of this previously sparsely studied region.

Exploring for the Future (EFTF) is an ongoing multiyear initiative by the Australian Government, conducted by Geoscience Australia, in partnership with state and Northern Territory government agencies and other partner research institutes. The first phase of the EFTF program (2016-2020) aimed to improve Australia’s desirability for industry investment in resource exploration in frontier or ‘greenfield’ regions across northern Australia. As part of the program, Geoscience Australia employed a range of both established and innovative techniques to gather new precompetitive data and information to develop new insight into the energy, mineral and groundwater resource potential across northern Australia. To maximise impact and to stimulate industry exploration activity, Geoscience Australia focussed activities in greenfield areas where understanding of resource potential was limited. In order to address this overarching objective under the EFTF program, Geoscience Australia led acquisition of two deep crustal reflection seismic surveys in the South Nicholson region, an understudied area of little previous seismic data, straddling north-eastern Northern Territory and north-western Queensland. The first survey, L210 South Nicholson 2D Deep Crustal Seismic Survey acquired in 2017, consisted of five overlapping seismic lines (17GA-SN1 to SN5), totalling ~1100 line-km. Survey L210 linked directly into legacy Geoscience Australia seismic lines (06GA-M1 and 06GA-M2) in the vicinity of the world-class Pb-Zn Century Mine in Queensland. The results from survey L210 profoundly revised our geological understanding of the South Nicholson region, and led to the key discovery of an extensive sag basin, the Carrara Sub-basin, containing highly prospective late Paleoproterozoic to Mesoproterozoic rocks with strong affinities with the adjacent Mount Isa Province and Lawn Hill Platform. To complement and expand on the outstanding success of the South Nicholson survey and to continue to explore the resource potential across the underexplored and mostly undercover South Nicholson and Barkly regions, a second seismic survey was acquired in late 2019, the Barkly 2D reflection survey (L212). The Barkly seismic survey comprises five intersecting lines (19GA-B1 to B5), totalling ~813 line-km, extending from the NT-QLD border in the south-east, near Camooweal, to the highly prospective Beetaloo Sub-basin in the north-west. The survey ties into the South Nicholson survey (L210), the recently acquired Camooweal 2D reflection seismic survey by the Geological Survey of Queensland and industry 2D seismic in the Beetaloo Sub-basin, leveraging on and maximising the scientific value and impact on all surveys. The Barkly reflection seismic data images the south-western margin of the Carrara Sub-basin and identified additional previously unrecognised, structurally-disrupted basins of Proterozoic strata, bounded by broadly northeast trending basement highs. Critically, the survey demonstrates the stratigraphic continuity of highly prospective Proterozoic strata from the Beetaloo Sub-basin into these newly discovered, but as yet unevaluated, concealed basins and into the Carrara Sub-basin, further attesting to the regions outstanding potential for mineral and hydrocarbon resources. This survey, in concert with the South Nicholson seismic survey and other complementary EFTF funded regional geochemical, geochronology and geophysical data acquisition surveys, significantly improves our understanding of the geological evolution, basin architecture and the resource potential of this previously sparsely studied region.

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).

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