<div>The Geoscience Australia magnetotellurics (MT) program collaborates with state and territory geological surveys, universities, and AuScope to acquire audio- (AMT), broadband- (BBMT), and long-period-MT (LPMT) data to help understand the electrical conductivity structure of the Australian continent.</div><div><br></div><div>This report collates the time-series and processed data, electrical conductivity models, and publications released for projects for which Geoscience Australia was the lead organisation, a collaborator, or an in-kind or financial supporter. For the most part, this report does not reference MT data, models or publications released by other parties for projects in which Geoscience Australia had no involvement. Please see Geoscience Australia’s AusLAMP, Exploring for the Future AusLAMP, and Regional Magnetotellurics webpages for more information.</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><strong>Output Type: </strong>Exploring for the Future Extended Abstract</div><div><br></div><div><strong>Short Abstract: </strong>The Australian Lithospheric Architecture Magnetotelluric project (AusLAMP) is a collaborative, national survey that aims to acquire long period magnetotelluric (MT) data at 0.5° spacing (~55 km) across the Australian continent. AusLAMP started in 2013 and is ~51% complete to date. Over the last decade, regional-scale conductivity/resistivity AusLAMP models have been produced following data acquisition campaigns, but a levelled national model has not emerged. Here we present the largest AusLAMP conductivity model incorporating 85% of data acquired to date. The model images the conductivity structure of the Australian lithosphere across most parts of central and eastern Australia, including Tasmania. The resolved resistivity structures broadly conform with identified major geological domains and crustal boundaries but also reveal significant variations within geological provinces, orogens and cratons. There are strong spatial associations between crustal/mantle conductors and copper and gold deposits and carbonatites, which provide further evidence that major lithospheric conductors control the distributions of a range of mineral systems. This new model is a powerful bottom-up approach to inform exploration, particularly in covered and under-explored regions.</div><div><br></div><div><strong>Citation: </strong>Duan J. & Huston D., 2024. AusLAMP - mapping lithospheric architecture and reducing exploration search space in central and eastern Australia. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts. Geoscience Australia, Canberra. https://doi.org/10.26186/149675</div>

<div> Airborne electromagnetic (AEM) data has been acquired at 20km line spacing across much of the Australian continent and conductivity models generated by inverting these data are freely available. Despite the wide line spacing these data are suitable for imaging the near surface and better understanding groundwater systems. Twenty-kilometre spaced AEM data acquired over the Cooper Creek floodplain using a fixed-wing towed system were inverted using deterministic and probabilistic methods. The Cooper Creek is an anabranching ephemeral river system in arid eastern central Australia. We integrated conductivity data with a range of surface and subsurface data to characterise the hydrogeology of the region and infer groundwater salinity from the shallow alluvial aquifer across a more than 14,000 km2 Cooper Creek floodplain. The conductivity data also revealed several examples of focused recharge through a river channel forming a freshwater lens within the more regional shallow saline groundwater system.</div><div>&nbsp;</div><div>This work demonstrates that regional AEM conductivity data can be a valuable tool for understanding groundwater processes at various scales with implications for how to responsibly manage water resources. This work is especially important in the Australian context where high quality borehole data is typically sparse, but high-quality geophysical and satellite data are often accessible.</div><div> </div> This presentation was given to the 8th International Airborne Electromagnetics Workshop (AEM2023) (https://www.aseg.org.au/news/aem-2023)

<div><strong>Yathong, Forbes, Dubbo, and Coonabarabran Airborne Electromagnetic Survey Blocks.</strong></div><div><br></div><div>Geoscience Australia (GA), in collaboration with the Geological Survey of New South Wales (GNSW), conducted an airborne electromagnetic (AEM) survey from April to June 2023. The survey spanned from the north-eastern end of the Yathong-Ivanhoe Trough and extended across the Forbes, Dubbo, and Coonabarabran regions of New South Wales.&nbsp;A total of 15, 090-line kilometres of new AEM and magnetic geophysical data were acquired. This survey was entirely funded by&nbsp;GSNSW and GA managed acquisition, quality control, processing, modelling, and inversion of the AEM data.</div><div><br></div><div>The survey was flown by Xcalibur Aviation (Australia) Pty Ltd using a 6.25 Hz HELITEM® AEM system. The survey blocks were flown at 2500-metre nominal line spacings, with variations down to 100 metres in the Coonabarabran block. It was flown following East-West line directions. Xcalibur also processed the acquired data. This data package includes the acquisition and processing report, the final processed AEM data, and the results of the contractor's conductivity-depth estimates. The data package also contains the results and derived products from a 1D inversion by Geoscience Australia with its own inversion software.</div><div><br></div><div>The survey will be incorporated and become part of the national AusAEM airborne electromagnetic acquisition program, which aims to provide geophysical information to support investigations of the regional geology and groundwater.</div><div><br></div><div><strong>The data release package contains:</strong></div><div><br></div><div>1. A data release package <strong>summary PDF document</strong></div><div>2. The <strong>survey logistics and processing report</strong> and HELITEM® system specification files</div><div>3. <strong>Final processed point located line data</strong> in ASEG-GDF2 format for the five areas</div><div> -final processed dB/dt electromagnetic, magnetic and elevation data</div><div> -final processed B field electromagnetic, magnetic and elevation data</div><div><strong> <em>Conductivity estimates generated by Xcalibur’s inversion&nbsp;</em></strong></div><div> -point located conductivity-depth line data output from the inversion in ASEG-GDF2 format</div><div> -graphical (PDF) multiplot conductivity stacks and section profiles for each flight line</div><div> -graphical (PNG) conductivity sections for each line</div><div> -grids generated from the Xcalibur’s inversion in ER Mapper® format (layer conductivities slices, DTM, X & Z component for each of the 25 channels, time constants, TMI)</div><div>4.<strong> ESRI shape and KML</strong> (Google Earth) files for the flight lines and boundary</div><div>5<strong>. Conductivity estimates generated by Geoscience Australia's inversion&nbsp;</strong></div><div> -point located line data output from the inversion in ASEG-GDF2 format</div><div> -graphical (pdf) multiplot conductivity sections for each line</div><div> -georeferenced (PNG) conductivity sections (suitable for pseudo-3D display in a 2D GIS)</div><div> -GoCAD™ S-Grid 3D objects (suitable for various 3D packages)</div><div> -Curtain image conductivity sections in log & liner colour stretch (suitable 3D display in GA’s EarthSci)</div><div><br></div><div><strong>Directory structure</strong></div><div>├── <strong>01_Report</strong></div><div>├── <strong>02_XCalibur_delivered</strong></div><div>│&nbsp;&nbsp; ├── * survey_block_Name</div><div>│ ├── cdi</div><div>│ │ ├── sections</div><div>│ │ └── stacks</div><div>│ ├── grids</div><div>│ │ ├── cnd</div><div>│ │ ├── dtm</div><div>│ │ ├── emxbf</div><div>│ │ ├── emxdb</div><div>│ │ ├── emxff</div><div>│ │ ├── emxzbf</div><div>│ │ ├── emzdb</div><div>│ │ ├── time_constant</div><div>│ │ └── tmi</div><div>│ ├── located_data</div><div>│ ├── maps</div><div>│ └── waveform</div><div>│&nbsp;&nbsp; </div><div>├── <strong>03_Shape&kml</strong></div><div>└── <strong>04_GA_Layer_Earth_inversion</strong></div><div> ├── * survey_block_Name</div><div> ├── GA_georef_sections</div><div> │ ├── linear-stretch</div><div> │ └── log-stretch</div><div> ├── GA_Inverted_conductivity_models</div><div> ├── GA_multiplots</div><div> └── GA_sgrids</div><div> </div> <b>Final Processed point located line data is available on request from clientservices@ga.gov.au - Quote eCat# 149118</b>

<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>

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

<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 a low emissions economy, strong 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>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. As part of the Exploring for the Future Program, Geoscience Australia has completed AusLAMP data acquisition at 32 sites across the southwest and southeast region of Western Australia. The data were acquired using LEMI-424 instruments and were processed using the LEMI robust remote referencing process code.&nbsp;</div><div><br></div><div>This data release contains acquired time series data and processed data at each site. The time series data are in original format (.txt) recorded by the data logger and in MTH5 hierarchical format. The open-source MTH5 Python package (https://github.com/kujaku11/mth5) was used to convert the recorded data into MTH5 format. The processed data are in Electrical Data Interchange (EDI) format.&nbsp;&nbsp;</div><div><br></div><div>We acknowledge the Geological Survey of Western Australia for assistance with field logistics and land access, traditional landowners, private landholders and national park authorities within the survey region, without whose cooperation these data could not have been collected.</div><div><br></div><div>Time series data is available on request from clientservices@ga.gov.au - Quote eCat#&nbsp;149416.</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>The dataset contained in this package and release consists of GA’s Layered-Earth-Inversion (GALEI, Brodie, 2016) conductivity-depth estimates from the AEM data, acquired over several areas of Western Australia, converted into SEG-Y format. The SEG-Y data standard was proposed by the Society of Exploration Geophysicists (SEG) standards committee (see Norris & Faichney 2002). Previously, the AEM data has been released as point located line data in conventional ascii format and is accessible through several of the following associated eCat records (<a href="https://pid.geoscience.gov.au/dataset/ga/146345">146345</a>, <a href="https://pid.geoscience.gov.au/dataset/ga/146042">146042</a>, <a href="https://pid.geoscience.gov.au/dataset/ga/144621">144621</a>, <a href="https://pid.geoscience.gov.au/dataset/ga/145265">145265</a> and <a href="https://pid.geoscience.gov.au/dataset/ga/147688">147688</a>). This SEG-Y data release is expected to benefit users who require the AEM modelled sections in SEG-Y format to assist in their interpretations, investigations and discovery of potential mineral, energy, and groundwater resources within Australia.&nbsp;</div>