The AusAEM Year 1 NT/QLD Airborne Electromagnetic Survey covers the Newcastle Waters and Alice Springs 1:1 Million map sheets in the Northern Territory, plus the Normanton and Cloncurry 1:1 Million map sheets in Queensland. The survey was flown at 20 kilometre line spacing and entails approximately 60,000 line kilometres of data in total. The data were acquired in 2017 and 2018 by CGG Aviation (Australia) Pty. Ltd. (CGG), under contract to Geoscience Australia, using the TEMPEST® airborne electromagnetic system. The data were also processed by CGG. This Tranche 1 data release package only contains approximately the first one third (19,500 line kilometres) of the survey data that were acquired between August 4 and October 7, 2017. The AusAEM Year 1 NT/QLD survey also included over 1,500 line kilometres of infill flying, that was funded by private exploration companies, in certain infill blocks within the survey area. These infill blocks and data are not part of this data release due to confidentiality agreements. The survey was commissioned by Geoscience Australia as part of the Exploring for the Future (EFTF) program. The EFTF program is led by Geoscience Australia (GA), in collaboration with the Geological Surveys of the Northern Territory, Queensland, South Australia and Western Australia, and is investigating the potential mineral, energy and groundwater resources in northern Australia and South Australia. The EFTF is a four-year $100.5 million investment by the Australian Government in driving the next generation of resource discoveries in northern Australia, boosting economic development across this region. This Data Release Package (Tranche 1, Phase 1) contains the final survey deliverables produced by the contractor CGG, including: (a) the operations and processing report, (b) final processed electromagnetic, magnetic and elevation point located line data, (c) final processed electromagnetic, magnetic and elevation grids, (d) conductivity estimates generated by the EM Flow® conductivity depth imaging algorithm, (e) graphical multiplots of line data and EM Flow® conductivity sections, (f) graphical stacked EM Flow® conductivity sections, (h) ESRI shapefiles containing the flight line locations. Future data release packages will contain data flown after October 7 2017 (Tranche 2, etc.) and further derived products (Phase 2, etc.).

To meet the increasing demand for natural resources globally, industry faces the challenge of exploring new frontier areas that lie deeper undercover. Here, we present an approach to, and initial results of, modelling the depth of four key chronostratigraphic packages that obscure or host mineral, energy and groundwater resources. Our models are underpinned by the compilation and integration of ~200 000 estimates of the depth of these interfaces. Estimates are derived from interpretations of newly acquired airborne electromagnetic and seismic reflection data, along with boreholes, surface and solid geology, and depth to magnetic source investigations. Our curated estimates are stored in a consistent subsurface data repository. We use interpolation and machine learning algorithms to predict the distribution of these four packages away from the control points. Specifically, we focus on modelling the distribution of the base of Cenozoic-, Mesozoic-, Paleozoic- and Neoproterozoic-age stratigraphic units across an area of ~1.5 million km2 spanning the Queensland and Northern Territory border. Our repeatable and updatable approach to mapping these surfaces, together with the underlying datasets and resulting models, provides a semi-national geometric framework for resource assessment and exploration. <b>Citation:</b> Bonnardot, M.-A., Wilford, J., Rollet, N., Moushall, B., Czarnota, K., Wong, S.C.T. and Nicoll, M.G., 2020. Mapping the cover in northern Australia: towards a unified national 3D geological model. 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.

<div> A key issue for explorers in Australia is the abundant sedimentary and regolith cover obscuring access to underlying potentially prospective rocks. &nbsp;Multilayered chronostratigraphic interpretation of regional broad line-spaced (~20&nbsp;km) airborne electromagnetic (AEM) conductivity sections have led to breakthroughs in Australia’s near-surface geoscience. &nbsp;A dedicated/systematic workflow has been developed to characterise the thickness of cover and the depth to basement rocks, by delineating contact geometries, and by capturing stratigraphic units, their ages and relationships. &nbsp;Results provide a fundamental geological framework, currently covering 27% of the Australian continent, or approximately 2,085,000&nbsp;km2. &nbsp;Delivery as precompetitive data in various non-proprietary formats and on various platforms ensures that these interpretations represent an enduring and meaningful contribution to academia, government and industry.&nbsp;The outputs support resource exploration, hazard mapping, environmental management, and uncertainty attribution.&nbsp;This work encourages exploration investment, can reduce exploration risks and costs, helps expand search area whilst aiding target identification, and allows users to make well-informed decisions. Presented herein are some key findings from interpretations in potentially prospective, yet in some cases, underexplored regions from around Australia.&nbsp;</div> This abstract was submitted & presented to the 8th International Airborne Electromagnetics Workshop (AEM2023) (https://www.aseg.org.au/news/aem-2023)

Exploring for the Future AusAEM Eastern Resources Corridor: 2021 Airborne Electromagnetic Survey: TEMPEST® airborne electromagnetic data and GALEI inversion conductivity estimates The accompanying data package, was released on 15 September August 2021 by Geoscience Australia (GA). The package contains AEM data from the AusAEM_20 East Resources Corridor survey, which was acquired across an area spanning from Bedourie in Queensland to Cape Jervis in South Australia, and from Tibooburra in New South Wales to Warrnambool in Victoria. The coverage is more than 600,000 square kilometres of south-eastern Australia. The regional survey was flown at a 20-kilometre nominal line spacing and entailed approximately 31,500 flight-line kilometres f geophysical data. The survey was flown in three phases, by Xcalibur Aviation (Australia) Pty. Ltd. (Xcalibur), formally CGG Aviation (Australia) Pty. Ltd. (CGG), under contract to Geoscience Australia, using the TEMPEST® airborne electromagnetic system. Xcalibur Aviation also processed the data. Geoscience Australia commissioned the Exploring for the Future AusAEM Eastern Resources Corridor survey as part of the Exploring for the Future (EFTF) program. The Exploring for the Future AusAEM program has been expanded with funding from the Geological Surveys of Western Australia and Queensland. Geoscience Australia acknowledges the valuable in-kind support from all Australian state and territory geological surveys in driving the new national AusAEM dataset. The program is designed to investigate the potential mineral, energy and groundwater resources of Australia driving the next generation of resource discoveries. GA managed the survey data acquisition, processing, contract, the quality control of the survey and generating two of the three inversion products included in the data package. The data release package comntains 1. A data release package summary PDF document. 2. The survey logistics and processing report and TEMPEST® system specification files 3. ESRI shape files for flight lines 4. Final processed point located line data in ASEG-GDF2 format 5. Conductivity estimates generated by Xcalibur, EMFlow conductivty-depth transform -point located line data output from the inversion in ASEG-GDF2 format -graphical (PDF) multiplot conductivity sections and profiles for each flight line -Grids generated from CGG's inversion conductivty-depth transform in ER Mapper® format (layer conductivities) 6. Conductivity estimates generated by Geoscience Australia's inversion -point located line data output from the inversion in ASEG-GDF2 format -graphical (PDF) multiplot conductivity sections and profiles for each flight line -GoCAD™ S-Grid 3D objects (suitable for various 3D packages)

<p>The AusAEM Year 1 NT/QLD Airborne Electromagnetic Survey covers the Newcastle Waters and Alice Springs 1:1 Million map sheets in the Northern Territory and the Normanton and Cloncurry 1:1 Million map sheets in Queensland. CGG Aviation (Australia) Pty. Ltd. flew the 67,700-line kilometre survey between 2017 and 2018 using the TEMPEST® airborne electromagnetic system. Flown at 20-kilometre line spacing, data were acquired and processed under contract to Geoscience Australia. <p>This data package supersedes and replaces two earlier releases: June 11, 2018, and December 2018 (eCatID 120948) with revised calibrations and processing. Along with the regionally spaced (20 km) flight lines, it now includes 1,500 line kilometres of infill flying that was funded by private exploration companies and not previously released in view of time-bounded confidentiality agreements. The survey was commissioned by Geoscience Australia as part of the Exploring for the Future (EFTF) program. The EFTF program is led by Geoscience Australia (GA), in collaboration with the Geological Surveys of the Northern Territory, Queensland, South Australia and Western Australia, and is investigating the potential mineral, energy and groundwater resources in northern Australia and South Australia. The EFTF is a four-year $100.5 million investment by the Australian Government in driving the next generation of resource discoveries in northern Australia, boosting economic development across this region. This Data Release (Phase 1) Package contains the final survey deliverables produced by the contractor CGG, including: <p>a) The operations and processing report. <p>b) Final processed electromagnetic, magnetic and elevation point located line data. <p>c) Final processed electromagnetic, magnetic and elevation grids. <p>d) Conductivity estimates generated by the EM Flow® conductivity depth-imaging algorithm. <p>e) Graphical multi-plots of line data and EM Flow® conductivity sections. <p>f) Graphical stacked EM Flow® conductivity sections. <p>g) ESRI shape-files containing the flight line locations. <p>An updated release package (Phase 2), which contains results from our in-house inversion of the EM data (from this Phase 1 release), which includes the regional and infill areas are downloadable from the link provided in the Downloads tab.

The discovery of strategically located salt structures, which meet the requirements for geological storage of hydrogen, is crucial to meeting Australia’s ambitions to become a major hydrogen producer, user and exporter. The use of the AusAEM airborne electromagnetic (AEM) survey’s conductivity sections, integrated with multidisciplinary geoscientific datasets, provides an excellent tool for investigating the near-surface effects of salt-related structures, and contributes to assessment of their potential for underground geological hydrogen storage. Currently known salt in the Canning Basin includes the Mallowa and Minjoo salt units. The Mallowa Salt is 600-800 m thick over an area of 150 × 200 km, where it lies within the depth range prospective for hydrogen storage (500-1800 m below surface), whereas the underlying Minjoo Salt is generally less than 100 m thick within its much smaller prospective depth zone. The modelled AEM sections penetrate to ~500 m from the surface, however, the salt rarely reaches this level. We therefore investigate the shallow stratigraphy of the AEM sections for evidence of the presence of underlying salt or for the influence of salt movement evident by disruption of near-surface electrically conductive horizons. These horizons occur in several stratigraphic units, mainly of Carboniferous to Cretaceous age. Only a few examples of localised folding/faulting have been noted in the shallow conductive stratigraphy that have potentially formed above isolated salt domes. Distinct zones of disruption within the shallow conductive stratigraphy generally occur along the margins of the present-day salt depocentre, resulting from dissolution and movement of salt during several stages. This study demonstrates the potential AEM has to assist in mapping salt-related structures, with implications for geological storage of hydrogen. In addition, this study produces a regional near-surface multilayered chronostratigraphic interpretation, which contributes to constructing a 3D national geological architecture, in support of environmental management, hazard mapping and resource exploration. <b>Citation: </b>Connors K. A., Wong S. C. T., Vilhena J. F. M., Rees S. W. & Feitz A. J., 2022. Canning Basin AusAEM interpretation: multilayered chronostratigraphic mapping and investigating hydrogen storage potential. In: Czarnota, K (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/146376

The AusAEM1 airborne electromagnetic survey extends across an area exceeding 1.1 million km2 over Queensland and the Northern Territory. Approximately 60,000 line kilometres of data were acquired at a nominal line spacing of 20 km (Ley-Cooper et al., 2020). To improve targeting and outcomes for mineral, energy and groundwater exploration, we conducted a regional interpretation of this dataset to characterise the subsurface geology of northern Australia. The interpretation includes the depth to chronostratigraphic surfaces, compilation of stratigraphic relationship information, and delineation of structural and electrically conductive features. In addition to help connecting correlative outcropping units separated by up to hundreds of kilometres, the results led to 3D mapping of palaeovalleys and prompted further investigation of electrical conductors and their relationship to structural features and mineralisation. Approximately 200,000 regional depth point measurements, each attributed with detailed geological information, are an important step towards a national geological framework, and offer a regional context for more detailed, smaller-scale AEM surveys. Refer to Wong et al., (2020) for more details on the AusAEM1 interpretation.

<div>This data package contains interpretations of airborne electromagnetic (AEM) conductivity sections in the Exploring for the Future (EFTF) program’s Eastern Resources Corridor (ERC) study area, in south eastern Australia. Conductivity sections from 3 AEM surveys were interpreted to provide a continuous interpretation across the study area – the EFTF AusAEM ERC (Ley-Cooper, 2021), the Frome Embayment TEMPEST (Costelloe et al., 2012) and the MinEx CRC Mundi (Brodie, 2021) AEM surveys. Selected lines from the Frome Embayment TEMPEST and MinEx CRC Mundi surveys were chosen for interpretation to align with the 20&nbsp;km line-spaced EFTF AusAEM ERC survey (Figure 1).</div><div>The aim of this study was to interpret the AEM conductivity sections to develop a regional understanding of the near-surface stratigraphy and structural architecture. To ensure that the interpretations took into account the local geological features, the AEM conductivity sections were integrated and interpreted with other geological and geophysical datasets, such as boreholes, potential fields, surface and basement geology maps, and seismic interpretations. This approach provides a near-surface fundamental regional geological framework to support more detailed investigations. </div><div>This study interpreted between the ground surface and 500&nbsp;m depth along almost 30,000 line kilometres of nominally 20&nbsp;km line-spaced AEM conductivity sections, across an area of approximately 550,000&nbsp;km2. These interpretations delineate the geo-electrical features that correspond to major chronostratigraphic boundaries, and capture detailed stratigraphic information associated with these boundaries. These interpretations produced approximately 170,000 depth estimate points or approximately 9,100 3D line segments, each attributed with high-quality geometric, stratigraphic, and ancillary data. The depth estimate points are formatted for compliance with Geoscience Australia’s (GA) Estimates of Geological and Geophysical Surfaces (EGGS) database, the national repository for standardised depth estimate points. </div><div>Results from these interpretations provided support to stratigraphic drillhole targeting, as part of the Delamerian Margins NSW National Drilling Initiative campaign, a collaboration between GA’s EFTF program, the MinEx CRC National Drilling Initiative and the Geological Survey of New South Wales. The interpretations have applications in a wide range of disciplines, such as mineral, energy and groundwater resource exploration, environmental management, subsurface mapping, tectonic evolution studies, and cover thickness, prospectivity, and economic modelling. It is anticipated that these interpretations will benefit government, industry and academia with interest in the geology of the ERC region.</div>

<div>A national compilation of airborne electromagnetic (AEM) conductivity–depth models from AusAEM (Ley-Cooper et al. 2020) survey line data and other surveys (see reference list in the attachments) has been used to train a conductivity model prediction for the 0-4 m and 30 m depth intervals. Over 460,000 training points/measurements were used in a 5 K-Fold training and validation split. A further 28,626 points/measurements were used to assess the out of sample performance (OOS; i.e. points not used in the model validation). Modelling of the conductivity values (i.e. measurements along the AEM survey lines) was performed using the gradient boosted (GB) tree algorithm. The GB model is a machine learning (ML) ensemble technique used for both regression and classification tasks (https://scikit-learn.org/stable/modules/generated/sklearn.ensemble.GradientBoostingRegressor.html). Samples along the flight-line were thinned to approximately one sample per 300 m. This avoided the situation where we could have more than one sample per pixel (i.e. features or covariates used in the model prediction have a cell or pixel size of 80 m) that could otherwise lead to over fitting. In addition, out of sample set used label clusters or groups to minimise overfitting. Here we use the median of the models as the conductivity prediction and the upper and lower percentiles (95th and 5th respectively) to measure the model uncertainty. Grids show conductivity (S/m) in log 10 units. The methodology used to generate these conductivity grids are overall similar to that described by Wilford, et al. 2022.</div><div>&nbsp;</div><div>Reported out-of-sample r-squares for the 0-4 m and 3 m depths are 0.76 and 0.74, respectively. The ML approach allows estimation of conductivity into areas where we do not have airborne electromagnetic survey coverage. Hence these model have a national extent. Where we do not have AEM survey coverage the model is finding relationships with the covariates and making informed estimates of conductivity in those areas. Where those relationships are not well understood (i.e. where we see a departure in the feature space characteristics from what the model can ‘see’) the model prediction is likely to be less certain. Differences in the features and their corresponding values ‘seen’ and used in the model versus the full feature space covering the entire continent are captured in the covariate shift map. High values in the shift model can indicate higher potential uncertainty or unreliability of the model prediction. Users therefore need to be mindful when interpreting this dataset, of the uncertainties shown by the 5th-95th percentiles, and high values in the covariate shift map.</div><div>&nbsp;</div><div>Datasets in this data package include:</div><div>&nbsp;</div><div>1. 0_4m_conductivity_prediction_median.tif</div><div>2. 0_4m_conductivity_lower_percentile_5th.tif</div><div>3. 0_4m_conductivity_upper_percentile_95th.tif</div><div>4. 30m_conductivity_prediction_median.tif</div><div>5.30m_conductivity_lower_percentile_5th.tif</div><div>6. 30m_conductivity_upper_percentile_95th.tif</div><div>7. National_conductivity_model_shift.tif</div><div>8. Full list of referenced AEM survey datasets used to train the model (word document)</div><div>9. Map showing the distribution of training and out-of-sample sites</div><div><br></div><div>All the Geotiffs (1-6) are in log (10) electrical conductivity siemens per metre (S/m).</div><div>&nbsp;</div><div>This work is part of Geoscience Australia’s Exploring for the Future program which 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><div><br></div><div><br></div><div><strong>Reference:</strong></div><div><br></div><div>Ley-Cooper, A. Y., Brodie, R.C., and Richardson, M. 2020. AusAEM: Australia’s airborne electromagnetic continental-scale acquisition program, Exploration Geophysics, 51:1, 193-202, DOI: 10.1080/08123985.2019.1694393</div><div><br></div><div>Wilford, J., LeyCooper, Y., Basak, S., Czarnota, K. 2022. High resolution conductivity mapping using regional AEM survey and machine learning. Geoscience Australia, Canberra. https://dx.doi.org/10.26186/146380</div>

The Exploring for the Future (EFTF) program is unmatched for the scale of geoscience data acquisition across northern Australia, covering 37 648 individual land parcels and 2.9 million km2. The scale of works has raised many new challenges for Geoscience Australia (GA) through the diverse range of field activities, and the numerous stakeholders from different social and cultural backgrounds, across multiple jurisdictions. Success of the program depended on the development and maintenance of a social licence to operate. This was broadly achieved for fieldwork activities through early engagement with stakeholders, including free, prior and informed consent. Here, we present two case studies of stakeholder engagement for facilitation of data collection: one focuses on broadscale, low-impact field activities associated with the AusAEM survey; and the other on Indigenous-focused engagement related to the Barkly Seismic Survey. Because of the complexity of project planning and managing such a large number of stakeholders, GA’s project governance team was expanded; it now includes a dedicated Land and Marine Access team and a commitment to adopt world-leading engagement practices. One practice is to consider impacts and benefits for all stakeholders—not just landholders—of field activities and data acquisition programs. This includes a plan for how the data are delivered back to the communities and stakeholders, and how information exchanges can be built into projects. The aim is for stakeholders to hold GA in the highest regard and understand the benefits to the Australian people, and ultimately their own communities, from the geoscientific data that GA produces. <b>Citation:</b> Mouthaan, R., Buchanan, S. and Sweeney, M, 2020. Land access and Indigenous engagement for Australian geoscience. 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.