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>

The EGGS database contains point depths to chronostratigraphic surfaces obtained from boreholes and four magnetic modelling methods. In regards to the depths obtained from inclined boreholes there are uncertainties on their measurement of the true vertical depths. These are currently being looked into and would be resolved in due course. Future development will include AEM, reflection seismic, MT and passive seismic. A Web Service will allow the public to download this data and will be accessed through the EFTF (Exploring for the Future) web portal.

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.

The Geoscience Australia Boreholes database (BOREHOLE) includes borehole header and directional survey data from: 1. boreholes drilled by Geoscience Australia and its predecessor organisations (BMR, AGSO), 2. all resource exploration boreholes drilled in Australian Commonwealth offshore marine jurisdictions, 3. a selection of Australian onshore mineral exploration, groundwater, geothermal and seismic boreholes, and 4. a small number of research-related boreholes outside of the Australian jurisdiction. Geoscience Australia is not a reporting or regulatory authority for borehole drilling. Borehole information in the Geoscience Australia 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 database, the custodian agency provided with the data should be consulted as the authoritative source.

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

<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.

<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>

<div>This dataset represents the second version of a compilation of borehole stratigraphic unit data on a national scale (Figure 1). It builds on the previous Australian Borehole Stratigraphic Units Compilation (ABSUC) Version 1.0 (Vizy &amp; Rollet, 2023a) with additional new or updated stratigraphic interpretation on key boreholes located in Figure 2. Its purpose is to consolidate and standardise publicly accessible information from boreholes, including those related to petroleum, stratigraphy, minerals, and water. This compilation encompasses data from states and territories, as well as less readily available borehole logs and interpretations of stratigraphy.</div><div>&nbsp;</div><div>This study was conducted as part of the National Groundwater Systems (NGS) Project within the Australian Government's Exploring for the Future (EFTF) program. 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. More information is available at http://www.ga.gov.au/eftf and https://www.eftf.ga.gov.au/national-groundwater-systems.</div><div>&nbsp;</div><div>As our understanding of Australian groundwater systems expands across states and territories, including legacy data from the 1970s and recent studies, it becomes evident that there is significant geological complexity and spatial variability in stratigraphic and hydrostratigraphic units nationwide. Recognising this complexity, there is a need to standardise diverse datasets, including borehole location and elevation, as well as variations in depth and nomenclature of stratigraphic picks. This standardisation aims to create a consistent, continent-wide stratigraphic framework for better understanding groundwater system for effective long-term water resource management and integrated resource assessments.</div><div>&nbsp;</div><div>This continental-scale compilation consolidates borehole data from 53 sources, refining 1,117,693 formation picks to 1,010,483 unique records from 171,396 boreholes across Australia. It provides a consistent framework for interpreting various datasets, enhancing 3D aquifer geometry and connectivity. Each data source's reliability is weighted, prioritising the most confident interpretations. Geological units conform to the Australian Stratigraphic Units Database (ASUD) for efficient updates. Regular updates are necessary to accommodate evolving information. Borehole surveys and dip measurements are excluded. As a result, stratigraphic picks are not adjusted for deviation, potentially impacting true vertical depth in deviated boreholes.</div><div>&nbsp;</div><div>This dataset provides:</div><div>ABSUC_v2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Australian stratigraphic unit compilation dataset (ABSUC)</div><div>ABSUC_v2_TOP&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;A subset of preferred top picks from the ABSUC_v2 dataset</div><div>ABSUC_v2_BASE&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;A subset of preferred base picks from the ABSUC_v2 dataset</div><div>ABSUC_BOREHOLE_v2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ABSUC Borehole collar dataset</div><div>ASUD_2023&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;A subset of the Australia Stratigraphic Units Database (ASUD)</div><div>&nbsp;</div><div>Utilising this uniform compilation of stratigraphic units, enhancements have been made to the geological and hydrogeological surfaces of the Great Artesian Basin, Lake Eyre Basin and Centralian Superbasin. This compilation is instrumental in mapping various regional groundwater systems and other resources throughout the continent. Furthermore, it offers a standardised approach to mapping regional geology, providing a consistent foundation for comprehensive resource impact assessments.</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. This package contains data generated in the field as part of stratigraphic drilling operations in the Delamerian region of the western New South Wales during 2023 funded through the Exploring for the Future program. A range of geological, geophysical and geochemical data are included, as well as associated borehole information such as core photographs. The data can be viewed and downloaded via the Geoscience Australia Portal - https://portal.ga.gov.au/. The data that is available is from several databases which are associated to this record. <i>These data are published with the permission of the CEO, Geoscience Australia. </i>

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.