The Exploring for the Future Program facilitated the acquisition of major geoscience datasets in northern Australia, where rocks are mostly under cover and the basin evolution, mineral, energy and groundwater resource potential are, in places, poorly constrained. In an effort to support sustainable, regional economic development and build stronger communities in these frontier areas, integration of new and legacy data within a consistent platform could enhance the recognition of cross-disciplinary synergies in sub-surface resource investigations. Here we present a case study in the South-Nicholson Basin, located in a poorly exposed area between the prospective Mt Isa Province and the McArthur Basin. Both regions host major base metal deposits, contain units prospective for energy resources, and hold significant groundwater resources in the overlying Georgina Basin. In this study, we interpret a subset of new regional-scale data, which include ~1 900 km of deep seismic reflection data and 60 000 line kilometres of AusAEM1 airborne electromagnetic survey, supplemented with legacy information. This interpretation refines a semi-continental geological framework, as input to national coverage databases and informs decision-making for exploration and groundwater resource management. This study provides a 3D chronostratigraphic cover model down to the Paleoproterozoic basement. We mapped the depth to the base of intervals corresponding to geological eras, as well as deeper pre-Neoproterozoic superbasin boundaries to refine the cover model. The depth estimates, based on the compilation, interpretation and integration of geological and geophysical datasets, inform the basement architecture controls on evolution of the basin, with several key outcomes: 1) expanded mapped size of the South Nicholson Basin, potentially, increasing prospectivity for hydrocarbons and basin-hosted mineralisation, 2) improved stratigraphic unit correlations across the region, 3) identification of major crustal structures, some of which are associated with mineralisation and springs, and 4) improved basin architecture definition, supporting future investigation of groundwater resources.

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.

With the increasing need to extend mineral exploration under cover, new approaches are required to better understand concealed geology, and to narrow the mineral prospectivity search-space. Hydrogeochemistry is a non-invasive exploration technique based on the premise that groundwater interacting with a deposit or supergene alteration can cause anomalous elemental and isotopic signatures down-gradient. Water chemistry can reflect mineralisation directly, but can also reveal other key components of a mineral system, including fluid-flow pathways (e.g. fault/fracture zones), evidence for mineral system traps (e.g. evaporites, shales), or metal sources (e.g. mafic rocks). The Northern Australia Hydrogeochemical Survey (NAHS) was a multiyear regional groundwater sampling program that aimed to understand the regional mineral potential within the Tennant Creek to Mt Isa area (Schroder et al. 2020). This presentation will explore the application of NAHS for investigating mineral potential of a region and present a workflow for establishing spatial or lithological baselines to evaluate hydrogeochemical anomalies. The Georgina Basin is well known for its phosphate potential, with several >1Mt deposits discovered in recent years such as Amaroo and Wonarah; however, the basin has been largely unmapped in terms of phosphate distribution under cover. This work focuses on a subset of 160 NAHS samples collected within two predominant aquifers of the Cambrian Georgina Basin (and time equivalents in the Wiso Basin). This focus restricts us to samples which experience a similar climate, recharge conditions, and aquifer compositions, reducing the hydrogeochemical variation that can mask intra-aquifer anomalies. Elevated dissolved phosphate, PO43- (normalised to HCO3- or Cl-), is observed in the groundwater on the eastern margin of the Georgina Basin. This region is known for Cambrian phosphorite deposits, with sampled bores proximal to a number of near-surface Georgina Basin phosphate deposits. We tested trace element (i.e. U, V and REEs) concentrations as a tool for discriminating phosphate dissolution, however at this regional scale of sampling, possible anomalies were only seen in few bores, thus it is difficult to conclude if this is a consistent relationship robust enough for exploration. More promising may be the use of REE ratios as another indicator of proximity to a phosphate deposit. Emsbo et al. (2015) note that REE compositions of phosphates are relatively consistent globally within a geological period. REE spidergrams of the high PO43- waters are similar to the average REE spidergram of Cambrian phosphates, which contrasts to the REE spidergram of low PO43- groundwaters. Cerium and Europium deviations make this relationship less diagnostic, thus we explore a series of REE ratios (i.e. Er/Dy, Er/Gd, Sm/Nd) for characterising PO43- relationships in groundwater, and use this to suggest other regions of the Georgina Basin with potential for subsurface phosphate deposits. References: Emsbo, P., McLaughlin, P.I., Breit, et al., 2015. Rare earth elements in sedimentary phosphate deposits: solution to the global REE crisis? Gondwana Research, 27(2), 776-785. Schroder, I.F., Caritat, P. de, Wallace, L., et al., 2020. Northern Australia Hydrogeochemical Survey: Final Data Release and Hydrogeochemical Atlas for EFTF. Geoscience Australia, Canberra. http://dx.doi.org/10.11636/Record.2020.015 Abstract presented at the 2021 Australian Earth Sciences Convention (AESC)

A key challenge in exploring Australian onshore sedimentary basins is limited seismic data coverage. Consequently, well logs are often the main datasets that can be used to understand the subsurface geology. The primary aim of this study was to develop a methodology for visualising the three-dimensional (3D) tectonostratigraphic architecture of sedimentary basins using well data, which can then be used to quickly screen areas warranting more detailed studies of resource potential. This project has developed a workflow that generates 3D well correlations using sequence stratigraphic well tops to visualise the regional structural and stratigraphic architecture of the Amadeus, Canning, Officer and Georgina basins in the Centralian Superbasin. Thirteen Neoproterozoic‒Paleozoic supersequence tops were interpreted in 134 wells. Three-dimensional well correlations provide an effective regional visualisation of the tectonostratigraphic architecture across the main depocentres. This study redefines the Centralian Superbasin as encompassing all western, northern and central Australian basins that had episodically interconnected depositional systems driven by regional subsidence during one or more regional tectonic events between the Neoproterozoic and middle Carboniferous. The Centralian Superbasin began to form during Neoproterozoic extension, and underwent several phases of partial or complete disconnection and subsequent reconnection of depositional systems during various regional tectonic events before final separation of depocentres at the culmination of the Alice Springs Orogeny. Regional 3D correlation diagrams have been generated to show the spatial distribution of these supersequences, which can be used to visualise the distribution of stratigraphic elements associated with petroleum, mineral and groundwater systems. <b>Citation: </b>Bradshaw, B., Khider, K., MacFarlane, S., Rollet, N., Carr, L. and Henson, P., 2020. Tectonostratigraphic evolution of the Centralian Superbasin (Australia) revealed by three-dimensional well correlations. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

This record presents nine new Sensitive High Resolution Ion Micro Probe (SHRIMP) U–Pb zircon results obtained under the auspices of the Exploring for the Future (EFTF) Programme, a four year, federally funded initiative to better understand the mineral, energy and groundwater potential of northern Australia. The results presented here are derived from eight sedimentary samples and one probable tuffaceous sample together belonging to the Mount Isa Province, South Nicholson Basin and Georgina Basin.

Small-angle neutron scattering (SANS) measurements were performed on 32 rock samples from the southern Georgina Basin, central Australia to assess nanopore anisotropy. Anisotropy can only be determined from oriented core material, hence the samples were cut perpendicular to bedding in cores selected from three wells that intersect the base of the hydrocarbon-bearing, organic-rich middle Cambrian Arthur Creek Formation; the latter is the source rock for both unconventional and conventional plays in the basin. The evolution of anisotropy of two-dimensional SANS intensity profiles with depth (for pore diameters ranging from 10 nm to 100 nm) was quantified and correlated with SANS intensity and total organic carbon (TOC) content. Our results confirm hydrocarbon generation at the base of the Arthur Creek Formation. The nanopore anisotropy in the basal Arthur Creek Formation at the well locations CKAD0001 (oil generation window) and MacIntyre 1 (late oil generation window) varies roughly according to normal compaction. When the Arthur Creek Formation is in the gas window, as sampled at Baldwin 1, there is a strong (negative) correlation between the average vertical-to-horizontal pore shape anisotropy and SANS intensity. The results indicate that unconventional gas production from organic-rich regions of over mature shale may be adversely affected by abnormal pore compaction.

This web service provides access to satellite imagery products for the identification of potential groundwater dependent ecosystems (GDEs) in the South Nicholson - Georgina region.

Australia’s search for petroleum began in the onshore basins where extensive areas of Paleozoic marine sequences, with some high-quality source rock intervals and spectacular outcrop, encouraged sporadic exploration for many decades. For these efforts, there were some rewards, including the discovery of the Mereenie oil field in Ordovician rocks, the Amadeus Basin in 1960s, and the Blina discovery in Devonian carbonates in the Canning Basin during the early 1980s. Since the late 1980s, however, the focus of exploration has shifted offshore where more and larger discoveries were made in the Mesozoic marginal basins, which today contain about 90% or more of Australia’s conventional oil and gas. Now, however, the focus has shifted back to the onshore, recognising the potential for shale and tight gas and oil in these older rocks. The onshore basin area under exploration license has nearly doubled from 2010 to 2012; several major international companies have joined local explorers in testing the worth of Australia’s lower Paleozoic and Proterozoic petroleum systems, and new discoveries have been made in several basins. Geoscience Australia and its partners in the state and NT surveys are undertaking new assessments and studies across a number of these basins. Extended abstract and presentation prepared for the APPEA Conference & Exhibition 2013, Brisbane. Citation: Bradshaw, M., Carr, L., Edwards, D.S., Hall, L., Laurie, J.R. 2013. Unconventional hydrocarbons - Australia's old rocks prove their worth. The APPEA Journal 53(2) 472-472 https://doi.org/10.1071/AJ12083

The Western Davenport region has been identified as an area of interest for future agricultural development. However, realisation of this potential depends on access to a reliable supply of groundwater, underpinned by rigorous geological and groundwater information. A three-dimensional stratigraphic model has been created for the Western Davenport area of the Southern Stuart Corridor project under the Exploring for the Future program. Our interpretation integrates airborne electromagnetic data with historical drillhole and outcrop data to improve geological and hydrogeological understanding. Results show that stratigraphies of the Wiso and Georgina basins are equivalent and laterally continuous in this area. This enables a more complete hydrostratigraphy to be defined and underpins improved hydrogeological conceptualisation. New hydrochemical data support the conceptual model that the aquifers of the Wiso and Georgina basins are interconnected at a regional scale. The initial assessment of water quality indicates that groundwater may support further agricultural development. Analysis of new water chemistry data has improved understanding of groundwater processes and potential areas of recharge. This work will inform management decisions to enhance the economic and social opportunities in the Western Davenport area, while protecting the environmental and cultural value of water resources. <b>Citation:</b> Northey, J.E., Clark, A.D., Smith, M.L. and Hostetler, S., 2020. Delineation of geology and groundwater resources in a frontier region: Western Davenport, Northern Territory. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

The Georgina Basin is a Neoproterozoic to Lower Devonian sedimentary basin covering 325,000 km² of western Queensland and the Northern Territory. It is a northwest-southeast-trending extensional basin, with prospective conventional and unconventional hydrocarbon targets within Cambrian and Ordovician carbonate and siliciclastic rock units in the southern depocentres. Recent biostratigraphic work has highlighted an age discrepancy in the prospective organic-rich `hot shale' in the base of the middle Cambrian Arthur Creek Formation. This unit is present in the two major southern depocentres, the Dulcie and Toko synclines, where it has previously been considered as correlative. Recent results, however, suggest that the basal `hot shale' is either significantly younger in the Toko Syncline than in the Dulcie Syncline, or represents a very condensed section in the former. Middle Cambrian carbon isotope excursions have been correlated across a number of Australian basins and can be used to test correlative models across the Georgina depocentres. In the current study, high resolution sampling across this middle Cambrian section has been carried out in a number of wells in the Dulcie Syncline and in the Undilla Sub-basin, where the age equivalent Inca Shale is penetrated. Carbon isotopes from organic carbon (kerogen) as well as carbon and oxygen isotope ratios of four carbonate mineral phases (calcite, ankerite, dolomite and siderite) were analysed. These new data are compared with the existing carbon isotope stratigraphy from the Dulcie and Toko synclines. Initial results corroborate the new biostratigraphic interpretation. This work will provide a detailed understanding of middle Cambrian isotope signatures and correlate this prospective unit across the southern Georgina Basin. Abstract presented at AAPG/SEG International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015