<div>This package contains Airborne Electromagnetic (AEM) data from the regional survey flown over the Upper Darling Floodplain in New South Wales (NSW), Australia between March-July 2022. Approximately 25,000 line km of transient EM and magnetic data were acquired. Geoscience Australia (GA) commissioned the survey in collaboration with the New South Wales Department of Planning and Environment (NSW DPE) as part of the Australian Government’s Exploring for the Future (EFTF) program (https://www.ga.gov.au/eftf). The NSW DPE were funding contributors to the AEM data collection. GA managed all aspects of the acquisition, quality control and processing of the AEM data.</div>

<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)

<div>The interpretation of AusAEM airborne electromagnetic (AEM) survey conductivity sections in the Canning Basin region delineates the geo-electrical features that correspond to major chronostratigraphic boundaries, and captures detailed stratigraphic information associated with these boundaries. This interpretation forms part of an assessment of the underground hydrogen storage potential of salt features in the Canning Basin region based on integration and interpretation of AEM and other geological and geophysical datasets. A main aim of this work was to interpret the AEM to develop a regional understanding of the near-surface stratigraphy and structural geology. This regional geological framework was complimented by the identification and assessment of possible near-surface salt-related structures, as underground salt bodies have been identified as potential underground hydrogen storage sites. This study interpreted over 20,000 line kilometres of 20&nbsp;km nominally line-spaced AusAEM conductivity sections, covering an area approximately 450,000 km2 to a depth of approximately 500&nbsp;m in northwest Western Australia. These 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 interpretation produced approximately 110,000 depth estimate points or 4,000 3D line segments, each attributed with high-quality geometric, stratigraphic, and ancillary data. The depth estimate points are formatted for Geoscience Australia’s Estimates of Geological and Geophysical Surfaces database, the national repository for formatted depth estimate points. Despite these interpretations being collected to support exploration of salt features for hydrogen storage, they are also intended for use in a wide range of other disciplines, such as mineral, energy and groundwater resource exploration, environmental management, subsurface mapping, tectonic evolution studies, and cover thickness, prospectivity, and economic modelling. Therefore, these interpretations will benefit government, industry and academia interested in the geology of the Canning Basin region.</div>

<div>In Australia, wide-spread sedimentary basin and regolith cover presents a key challenge to explorers, environmental managers and decision-makers, as it obscures underlying rocks of interest. To address this, a national coverage of airborne electromagnetics (AEM) with a 20&nbsp;km line-spacing is being acquired. This survey is acquired as part of the Exploring for the Future program and in collaboration with state and territory geological surveys. This survey presents an opportunity for regional geological interpretations on the modelled AEM data, helping constrain the characteristics of the near-surface geology beneath the abundant cover, to a depth of up to ~500&nbsp;m.</div><div> The AEM conductivity sections were used to delineate key chronostratigraphic boundaries, e.g. the bases of geological eras, and provide a first-pass interpretation of the subsurface geology. The interpretation was conducted with a high level of data integration with boreholes, potential fields geophysics, seismic, surface geology maps and solid geology maps. This approach led to the construction of well-informed geological interpretations and provided a platform for ongoing quality assurance and quality control of the interpretations and supporting datasets. These interpretations are delivered across various platforms in multidimensional non-proprietary open formats, and have been formatted for direct upload to Geoscience Australia’s (GA) Estimates of Geological and Geophysical Surfaces (EGGS) database, the national repository of multidisciplinary subsurface depth estimates.</div><div> These interpretations have resulted in significant advancements in our understanding of Australia’s near-surface geoscience, by revealing valuable information about the thickness and composition of the extensive cover, as well as the composition, structure and distribution of underlying rocks. Current interpretation coverage is ~110,000 line kilometres of AEM conductivity sections, or an area &gt;2,000,000&nbsp;km2, similar to the area of Greenland or Saudi Arabia. This ongoing work has led to the production of almost 600,000 depth estimate points, each attributed with interpretation-specific metadata. Three-dimensional line work and over 300,000 points are currently available for visualisation, integration and download through the GA Portal, or for download through GA’s eCat electronic catalogue. </div><div> These interpretations demonstrate the benefits of acquiring broadly-spaced AEM surveys. Interpretations derived from these surveys are important in supporting regional environmental management, resource exploration, hazard mapping, and stratigraphic unit certainty quantification. Delivered as precompetitive data, these interpretations provide users in academia, government and industry with a multidisciplinary tool for a wide range of investigations, and as a basis for further geoscientific studies.</div> Abstract submitted and presented at 2023 Australian Earth Science Convention (AESC), Perth WA (https://2023.aegc.com.au/)

<div>In July 2022 an airborne electromagnetic (AEM) survey was flown over and around the proposed site of the National Radioactive Waste Management Facility near the township of Kimba in South Australia.&nbsp;The survey was commissioned by the Australian Radioactive Waste Agency, and was project managed by Geoscience Australia. The survey has Geoscience Australia airborne survey project number P5008.</div><div><br></div><div>The survey was flown by Skytem Australia Pty Ltd using its SkyTEM312Fast AEM system.&nbsp;The survey was conducted on east-west lines at 500 m spacing, with a smaller central focus area of 100 m spaced lines, acquiring a total of 2,545 line kilometres of data. Skytem Australia Pty Ltd also processed the data.</div><div><br></div><div>This data package includes the acquisition and processing report, the final processed AEM data and the results of the 1D laterally constrained inversion of the data to conductivity-depth estimates that was carried out by the contractor.</div>

<div>This document describes Geoscience Australia’s standard operating procedure for acquiring long-period magnetotelluric (MT) data using equipment supplied by LEMI LLC. It is current as at April 2024. Users should check periodically for updated versions.</div><div><br></div><div>The procedure is based on the use of the LEMI-424 magnetotelluric station, comprising:</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;LEMI-424 data logger</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;LEMI-039 3-component analog magnetometer and cable</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;LEMI-701 electrodes</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;GPS receiver</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;electric-line interface box</div><div><br></div><div>Geoscience Australia supplements this equipment with the addition of:</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a Pelican equipment box to hold and transport the equipment</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;an acrylic housing to protect the LEMI-039 magnetometer</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;four 50&nbsp;m electrode cables</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a brass earth stake and cable</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a 12&nbsp;V battery</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a solar panel</div><div><br></div>

<div>The Magnetotelluric (MT) Sites database contains the location of sites where magnetotelluric (MT) data have been acquired by surveys. These surveys have been undertaken by Geoscience Australia and its predecessor organisations and collaborative partners including, but not limited to, the Geological Survey of New South Wales, the Northern Territory Geological Survey, the Geological Survey of Queensland, the Geological Survey of South Australia, Mineral Resources Tasmania, the Geological Survey of Victoria and the Geological Survey of Western Australia and their parent government departments, AuScope, the University of Adelaide, Curtin University and University of Tasmania. Database development was completed as part of Exploring for the Future (EFTF) and the database will utilised for ongoing storage of site information from future MT acquisition projects beyond EFTF. Location, elevation, data acquisition date and instrument information are provided with each site. The MT Sites database is a subset of tables within the larger Geophysical Surveys and Datasets Database. </div><div><br></div><div>The resource is accessible via the Geoscience Australia Portal&nbsp;(https://portal.ga.gov.au/), use Magnetotelluric as your search term to find the relevant data.</div>

The Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) is a collaborative national survey that acquires long-period magnetotelluric (MT) data on a half-degree grid spacing across Australia. This national scale survey aims to map the electrical conductivity/resistivity structure in the crust and mantle beneath the Australian continent, which provides significant additional information about Australia’s geodynamic framework as well as valuable pre-competitive data for resource exploration. Geoscience Australia in collaboration with the Geological Survey of New South Wales (GSNSW) has completed AusLAMP data acquisition at 321 sites across the state of NSW. The data were acquired using LEMI-424 instruments and were processed using the Lemigraph software. The processed data in EDI format and report of field acquisition, data QA/QC, and data processing have been released in 2020 (https://pid.geoscience.gov.au/dataset/ga/132148). This data release contains acquired time series data at each site in two formats: 1. MTH5, a hierarchical data format. The open-source MTH5 Python package (https://github.com/kujaku11/mth5) was used to convert the recorded LEMI data into MTH5 format. 2. Text file (*.TXT). This is the original format recorded by the LEMI-424 data logger. We acknowledge the traditional landowners, private landholders and national park authorities within the survey region, without whose cooperation these data could not have been collected. <b>Data is available on request from clientservices@ga.gov.au - Quote eCat# 148544</b>

<div>Long-period magnetotelluric (MT) data from the Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP), collected as part of Geoscience Australia’s Exploring for the Future program with contributions from the Northern Territory Geological Survey and the Geological Survey of Queensland, provide important first-order information for resolving large-scale lithospheric architecture and identifying the broad footprint of mineral systems in northern Australia. Large-scale crust/mantle conductivity anomalies map pathways of palaeo-fluid migration which is an important element of several mineral systems. For example, the Carpentaria conductivity anomaly east of Mount Isa and the Croydon, Georgetown to Greenvale conductivity anomaly are highly conductive lithospheric-scale structures, and show spatial correlations with major suture zones and known mineral deposits. These results provide evidence that some mineralisation occurs at the gradient of or over highly conductive structures at lower crustal and lithospheric mantle depths, which may represent fertile source regions for mineral systems. These observations provide a powerful means of highlighting prospective greenfield areas for mineral exploration in under-explored and covered regions.</div><div><br></div><div>Higher resolution scale-reduction MT surveys refine the geometry of some conductive anomalies from AusLAMP data, and investigate whether these deep conductivity anomalies link to the near surface. These links may act as conduits for crustal/mantle scale fluid migration to the upper crust, where they could form mineral deposits. For example, data reveals a favourable crustal architecture linking the deep conductivity anomaly or fertile source regions to the upper crust in the Cloncurry region. In addition, high-frequency MT data help to characterise cover and assist with selecting targets for drilling and improve the understanding of basement geology.</div><div><br></div><div>These results demonstrate that integration of multi-scale MT surveys is an effective approach for mapping lithospheric-scale features and selecting prospective areas for mineral exploration in covered terranes with limited geological knowledge.</div><div><br></div><div>Some models in this presentation were produced on the National Computational Infrastructure, which is supported by the Australian government. Abstract presented to the Australian Institute of Geoscientists – ALS Friday Seminar Series: Geophysical and Geochemical Signatures of Queensland Mineral Deposits October 2023 (https://www.aig.org.au/events/aig-als-friday-seminar-series-geophysical-and-geochemical-signatures-of-qld-mineral-deposits/)

MinEx CRC Mundi Airborne Electromagnetic Survey, NSW, 2021: XCITE® AEM data and conductivity estimates The package contains processed data from the “MinEx CRC Mundi Airborne Electromagnetic Survey” that was flown over the Curnamona Orogen and overlying Eromanga and Lake Eyre basins, north of Broken Hill, in Western New South Wales. The 2,940 line regional survey was flown east-west at 2.5 km nominal line spacing in 2021 by New Resolution Geophysics Pty Ltd (NRG) using the XCITE® airborne electromagnetic system. The Geological Survey of New South Wales commissioned the survey as part of the MinEx Cooperative Research Centre’s (MinEx CRC) National Drilling Initiative (NDI), the world’s largest mineral exploration collaboration. It brings together industry, government, research organisations and universities to further our understanding of geology, mineral deposits and groundwater resources in areas where rocks aren’t exposed at earth’s surface. The Geological Survey of New South Wales is a major participant in the NDI program, committing $16 million to the program over 10 years. In NSW, the program focuses on five areas in the state’s central and far west, where metallic minerals potentially exist under a layer of younger barren geology. These areas are North Cobar, South Cobar, Broken Hill (Mundi), Forbes and Dubbo. Geoscience Australia is also a major participant in the NDI, committing $50 million Australia-wide over the ten years of the MinEx CRC. Geoscience Australia partly funded the survey by providing funds for an additional 940 line kilometres of data acquisition to broaden the geographical reach of the survey under the Exploring for the Future Darling-Curnamona-Delamerian Project. Additionally, Geoscience Australia provided in-kind support to the project by managing the survey data acquisition and processing, undertaking the quality control of the survey and generating one of the two inversions and associated derived products that are 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 XCITE® system specification files 3. ESRI shape files for the flight lines and boundary 4. KML (Google Earth) files of the flight lines 5. Final processed point located dB/dt electromagnetic, magnetic and elevation data - in ASEG-GDF2 format - in Geosoft GDB format 6. Final processed point located BField electromagnetic, magnetic and elevation data - in ASEG-GDF2 format - in Geosoft GDB format 7, Multiplots -graphical (PDF) multiplot profiles and estimated conductivity sections (NRG inversion) for each flight line 8. Conductivity estimates generated by NRG’s inversion -point located line data output from the inversion in ASEG-GDF2 format -point located line data output from the inversion in Geosoft GDB format -graphical (JPEG) multiplot conductivity sections and profiles for each line -georeferenced (PNG) conductivity sections (suitable for pseudo-3D display in a 2D GIS) -GoCAD™ S-Grid 3D objects (suitable for various 3D packages) -Curtain image conductivity sections (suitable 3D display in GA’s EarthSci) -grids generated from the NRG inversion in ER Mapper® format (layer conductivities, depth slices, elevation slices) -georeferenced TIFF images generated from the grids above with accompaning world files for georegerencing (layer conductivities, depth slices, elevation slices) -images generated from the grids above (layer conductivities, depth slices, elevation slices) 9. Conductivity estimates generated by Geoscience Australia's inversion -point located line data output from the inversion in ASEG-GDF2 format -graphical (JPEG) multiplot conductivity sections and profiles for each line -georeferenced (PNG) conductivity sections (suitable for pseudo-3D display in a 2D GIS) -GoCAD™ S-Grid 3D objects (suitable for various 3D packages) -Curtain image conductivity sections (suitable 3D display in GA’s EarthSci) -grids generated from the NRG inversion in ER Mapper® format (layer conductivities, depth slices, elevation slices) -georeferenced TIFF images generated from the grids above with accompaning world files for georegerencing (layer conductivities, depth slices, elevation slices) -images generated from the grids above (layer conductivities, depth slices, elevation slices) Directory structure ├── report ├── shapefiles ├── kml ├── line_data_dbdt ├── line_data_bfield ├── multiplots ├── contractor_inversion │   ├── multiplot_sections │   ├── earthsci │   │   └── Contractor-Inversion │   │   ├── jpeg │   │   ├── geometry │   │   └── MinEx_CRC_Mundi_AEM_Contractor-Inversion │   ├── georef_sections │   ├── gocad_sgrids │   ├── grids │   │   ├── layers │   │   ├── depth_slice │   │   └── elevation_slice │   ├── images │   │   ├── layers │   │   ├── layers_northwest_sunangle │   │   ├── depth_slice_northwest_sunangle │   │   ├── depth_slice │   │   ├── elevation_slice │   │   └── elevation_slice_northwest_sunangle │   ├── line_data │   │   ├── geosoft │   │   └── aseggdf2 │   └── georef_images │   ├── layers_northwest_sunangle │   ├── layers │   ├── depth_slice │   ├── depth_slice_northwest_sunangle │   ├── elevation_slice_northwest_sunangle │   └── elevation_slice ├── ga_inversion    ├── georef_sections    ├── gocad_sgrids    ├── grids    │   ├── depth_slice    │   ├── layers    │   └── elevation_slice    ├── images    │   ├── layers    │   ├── layers_northwest_sunangle    │   ├── depth_slice    │   ├── elevation_slice_northwest_sunangle    │   ├── elevation_slice    │   └── depth_slice_northwest_sunangle    ├── multiplot_sections    ├── line_data    ├── earthsci    │   └── GA-Inversion    │   ├── geometry    │   ├── jpeg    │   └── MinEx_CRC_Mundi_AEM_GA-Inversion    └── georef_images    ├── layers    ├── layers_northwest_sunangle    ├── depth_slice_northwest_sunangle    ├── depth_slice    ├── elevation_slice    └── elevation_slice_northwest_sunangle