<div>This report and associated data package provide a compilation of biostratigraphic summaries, borehole logs, and stratigraphic correlations for key boreholes across the Amadeus, Officer and Georgina basins in the Paleozoic‒Neoproterozoic Centralian Superbasin and in the underlying older Mesoproterozoic South Nicholson and southern McArthur basins, laying the groundwork for further studies. This study is part of Geoscience Australia’s National Groundwater Systems project in the Exploring for the Future (EFTF) program.</div><div>This work compiles publicly available borehole data to enhance regional stratigraphic understanding. Future studies should incorporate outcrop constraints, geophysical data, and additional geological dating, alongside collaboration with experts to validate sequence chronostratigraphic correlations. The stratigraphic framework aligns geological units with timeframes, enabling consistent interbasinal correlation to group aquifers and aquitards and sedimentary mapping across lithologies and time periods. This alignment supports the integration of hydrostratigraphic classifications, potentially revealing a more accurate model of water flow connectivity over geological time units. The compilation standardises borehole log interpretation and integrates geological and hydrogeological data, contributing to national databases, exploration guidance, improving groundwater understanding, and resource impact assessments for decision-making across various groundwater, energy and minerals disciplines.</div><div>The study builds on previous EFTF program work (e.g., Bradshaw et al., 2021; Khider et al., 2021; Carson et al., 2023; Anderson et al., 2023) and legacy studies across Australia, addressing challenges in understanding groundwater systems due to limited subsurface geology knowledge and fragmented data across jurisdictions. A nationally coordinated approach is essential, with well logs playing a key role in interpreting subsurface geology. The mapping process involves interpolating between surface outcrops and subsurface strata using borehole data, integrated with geophysical interpretations. The goal is to create a consistent 3D geological framework across time-equivalent basins and jurisdictions, enabling consistent groundwater system assessments and water flow path analysis at regional and national scales.</div><div>Although not intended to be a major re-interpretation of existing data, this stratigraphy review updates stratigraphic picks where necessary to ensure a consistent interpretation across the study area. This framework is based on the 13 Centralian Supersequences defined in Bradshaw et al. (2021). Using this framework, a revised stratigraphic chart is proposed in this study to align geological units across the Officer, Amadeus, and Georgina basins with the geological time scale (Gradstein et al., 2020), incorporating significant events, such as major glaciations, orogens and other tectonic movements. </div><div>This report aims to summarise the main biostratigraphic groups used, where they have been found, and provide a detailed list of the reports available. Existing biostratigraphic data from 142 boreholes in the Georgina, Amadeus, and Officer basins and underlying older southern McArthur and South Nicholson basins, were compiled to improve regional correlations, addressing data gaps identified in previous studies. Due to time constraints, only the five fossil groups found most in borehole data are included, such as trilobites, palynology, conodonts, stromatolites and small shelly fossils. However, outcrop data provides a much larger dataset and set of fossil groups and will need to be incorporated for future studies. Outcrop biostratigraphic data was excluded here, as the focus of this study was collating borehole data. Efforts were made to refine and update formation picks, ensuring consistency in correlations across larger areas. The correlation of geological units and their assignment to the corresponding 13 Centralian Supersequences in 272 key boreholes provide a foundational stratigraphic framework. Challenges include limited biostratigraphic data, diverse dating methods, and complex structural histories in the studied basins. Problems and inconsistencies in the input data or current interpretations are highlighted to suggest where further studies or investigations may be useful. Borehole correlation transects have been established across each of the basins (20 in total), displaying age data points along with formation picks and supersequence divisions. While these simple 2D transects may not capture the structural complexity of specific areas, they provide a broad overview of the interrelationships between different units across each basin.</div><div>The datasets compiled and used in this study are in Appendix A (Biostratigraphic data) and Appendix B (Borehole stratigraphic data).</div>

Mineral exploration in Australia faces the challenge of declining discovery rates despite continued exploration investment. The UNCOVER roadmap, developed by stakeholders from industry, government and academia, has highlighted the need for discovering mineral resources in areas of cover. In these areas, potentially prospective basement is covered by regolith, including transported sediment, challenging many traditional exploration methods designed to probe outcrop or shallow subcrop. Groundwater-mineral interaction in the subsurface has the potential to give the water geochemical and isotopic characteristics that may persist over time and space. Geoscience Australia’s hydrogeochemistry for mineral exploration project, part of the Exploring for the Future Programme, aims to use groundwater chemistry to better understand the bedrock-regolith system and develop new methods for recognising mineral system footprints within and below cover. During the 2017 dry season (May to September), ~150 groundwater samples (including QC samples) were collected from pastoral and water supply bores in the regions of Tennant Creek and McArthur River, Northern Territory. The Tennant Creek region has a demonstrated iron oxide-hosted copper-gold-iron(-bismuth) mineral potential in the Paleoproterozoic and Mesoproterozoic basement and vast areas of regolith cover. Among the critical elements of this mineral system, the presence/absence of redox contrasts, iron enrichment, presence of sulfide minerals, and carbonaceous intervals can potentially be diagnosed by the elemental and isotopic composition of groundwater. The McArthur River region, in contrast, has demonstrated sediment-hosted stratiform lead-zinc-silver mineral potential in the Paleoproterozoic to Neoproterozoic basement and also vast areas of regolith cover. Here, critical mineral system elements that have the potential to be identified using groundwater geochemistry include the presence of felsic rocks (lead source), carbonate rocks (zinc source), basinal brines, dolomitic black shales (traps), and evaporite-rich sequences. Preliminary results will be presented and interpreted in the context of these mineral systems.

This web service provides links to access pictures and documents for any geological or geophysical feature data that are delivered by complementary feature services for these data, including but not limited to: boreholes, field sites, structures, stratigraphic units, samples, mines, mineral deposits and mineral occurrences, along with descriptions of those objects.

This technical report details the methods and results the drilling programs of the Upper Burdekin Groundwater Project conducted as part of Exploring for the Future (EFTF)—an eight year, $225 million Australian Government funded geoscience data and information acquisition program focused on better understanding the potential mineral, energy and groundwater resources across Australia. This report was written by Queensland Government collaborators in the Department of Environment and Science, and is published here as supplied to Geoscience Australia at the conclusion of the project. The drilling program itself was conducted by the Department of Environment and Science as part of the Upper Burdekin Groundwater Project. A total of 17 holes were drilled in 2017-18 at 13 sites with a total combined depth of 943.2 metres. These comprise selected locations across both the Nulla Basalt Province and McBride Basalt Province. A network of 15 monitoring bores were constructed with two test holes backfilled and decommissioned.

This OGC conformant web service delivers data from Geoscience Australia's Boreholes database (borehole header and directional survey data) and associated geological observations (lithostratigraphic data). The data includes records of boreholes drilled by Geoscience Australia and its predecessor organisations (BMR, AGSO), all boreholes drilled in Australian Commonwealth offshore marine jurisdictions, and a selection of onshore boreholes drilled by government and private entities. Where possible this service conforms to the GeoSciML v4.1 data transfer standard. Geoscience Australia is not a reporting or regulatory authority for borehole drilling. Borehole information in Geoscience Australia's Boreholes database is sourced from various regulatory authorities in the States, Northern Territory and Commonwealth governments for Geoscience Australia research purposes. Where Geoscience Australia is not the custodian of borehole data provided in this web service, the custodian agency provided with the data should be consulted as the authoritative source. The data dictionary for this web service is at <a href="https://d28rz98at9flks.cloudfront.net/144576/144576_00_3.pdf">https://d28rz98at9flks.cloudfront.net/144576/144576_00_3.pdf</a>. For information on borehole status definitions, refer to <a href="https://db-content.ga.gov.au/data_dictionary/Borehole_Status_vocabulary_2021.pdf">https://db-content.ga.gov.au/data_dictionary/Borehole_Status_vocabulary_2021.pdf</a>

We have used Audio-frequency Magnetotelluric (AMT) data to characterise cover and to estimate depth to basement for a number of regional drilling programs in geologically different regions across Australia. We applied deterministic and probabilistic inversion methods to derive 2D and 1D resistivity models. We have also used borehole results to ground-truth and validate the resistivity models and to improve geophysical interpretations. In the East Tennant region, borehole lithology and wireline logging demonstrates that the modelled AMT response is due to bulk conductivity/resistivity of the cover and basement rocks. The groundwater in the region is suitable for cattle drinking water, thus is of low overall salinity and is regarded as having little effect on bulk conductivity. Therefore the bulk conductivity/resistivity is due primarily to bulk mineralogy and the success of using the AMT models to predict cover thickness is shown to be dependent on whether the bulk mineralogy of cover and basement rocks are sufficiently different to provide a detectable conductivity contrast, and the sensitivity of the AMT response with increasing depth. In areas where there is sufficient difference in bulk mineralogy and where the stratigraphy is simple, AMT models predict the cover thickness with great certainty, particularly closer to the Earth’s surface. However, the geological system is not always simple, and we have provided examples where the AMT models provide an ambiguous response that needs to be interpreted with other data (e.g. drilling, wireline logging, potential field modelling) to validate the AMT model result. Overall, we conclude that the application of the method has been validated and the results can compare favourably with borehole stratigraphy logs once geological (i.e. bulk mineralogical) complexity is understood. This demonstrates that the method is capable of identifying major stratigraphic structures with resistivity contrasts. Our results have assisted with the planning of regional drilling programs and have helped to reduce the uncertainty and risk associated with intersecting targeted stratigraphic units in covered terrains. <b>Citation:</b> Jiang, W., Roach, I. C., Doublier, M. P., Duan, J., Schofield, A., Clark, A., & Brodie, R. C. Application of audio-frequency magnetotelluric data to cover characterisation – validation against borehole petrophysics in the East Tennant region, Northern Australia. <i>Exploration Geophysics</i>, 1-20, DOI: 10.1080/08123985.2023.2246492

The Geoscience Australia (GA) Inorganic Geochemistry database (GEOCHEM) contains chemical analyses and analytical metadata from rocks and regolith materials. The majority of analysed samples are from mapping and sampling programs in Australia by GA and its predecessor organisations (BMR, AGSO), along with a considerable collection from the Australian Antarctic Territory. A small number of analyses exist from Papua New Guinea and offshore sampling programs. The data set is currently used for internal GA consumption and is served off an application within the GA portal. As an enhancement, this data would be altered in terms of its structure adding more information out of such analyses. In addition, the data would me made compliant following GGIC standards. The data would be published within internal GA as well as to external third parties, through OGC web services viz. WMS and WFS.

<div>As part of the Delamerian Margins NSW National Drilling Initiative campaign, seventeen stratigraphic boreholes were drilled between Broken Hill and Wentworth, in Western NSW. These holes were designed to test stratigraphic, structural, and mineral systems questions in the New South Wales portion of the Delamerian Margin. Drilling was conducted between March and June 2023 and was undertaken by Geoscience Australia in collaboration with MinEx CRC. This report outlines basic borehole targeting rationale, borehole metadata, and analyses performed immediately following drilling to accompany data available through the Geoscience Australia portal.</div><div><br></div><div>Geoscience Australia’s Exploring for the Future 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 net zero emissions, strong, sustainable 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.</div>

This OGC conformant web service delivers data from Geoscience Australia's Boreholes database (borehole header and directional survey data) and associated geological observations (lithostratigraphic data). The data includes records of boreholes drilled by Geoscience Australia and its predecessor organisations (BMR, AGSO), all boreholes drilled in Australian Commonwealth offshore marine jurisdictions, and a selection of onshore boreholes drilled by government and private entities. Where possible this service conforms to the GeoSciML v4.1 data transfer standard. Geoscience Australia is not a reporting or regulatory authority for borehole drilling. Borehole information in Geoscience Australia's Boreholes database is sourced from various regulatory authorities in the States, Northern Territory and Commonwealth governments for Geoscience Australia research purposes. Where Geoscience Australia is not the custodian of borehole data provided in this web service, the custodian agency provided with the data should be consulted as the authoritative source. The data dictionary for this web service is at <a href="https://d28rz98at9flks.cloudfront.net/144578/144578_00_3.pdf">https://d28rz98at9flks.cloudfront.net/144578/144578_00_3.pdf</a>. For information on borehole status definitions, refer to <a href="https://db-content.ga.gov.au/data_dictionary/Borehole_Status_vocabulary_2021.pdf">https://db-content.ga.gov.au/data_dictionary/Borehole_Status_vocabulary_2021.pdf</a>

<b>This record has been superseded by eCat 126310</b> <p>Geoscience Australia defines a borehole as the generalized term for any narrow shaft drilled in the ground, either vertically or horizontally, and includes Mineral Drillholes, Petroleum Wells and Water Bores along with a variety of others types, but does not include Costean, Trench or Pit. <p>For the purpose of a borehole as defined by GeoSciML Borehole, the dataset has been restricted to onshore and offshore Australian boreholes, and bores that have the potential to support geological investigations and assessment of a variety of resources.