<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 Australian wide airborne electromagnetic programme AusAEM stands as the largest survey of its kind aiming to cover the Australian continent at approximately 20 km line-spacing. It is transforming resource exploration, unveiling potential minerals and groundwater.&nbsp;</div><div><br></div><div>The open-access nature of AusAEM data and the modelling codes developed around it encourages collaboration between governments, industry, and academia, fostering a community focused on advancing geoscientific research and exploration.</div><div><br></div><div>Overall, the AusAEM program is an asset that can drive economic growth, support sustainable resource management, and enhance scientific understanding of Australia’s geological landscape.</div><div><br></div>

<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>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>

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>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><strong>Output Type: </strong>Exploring for the Future Extended Abstract</div><div><br></div><div><strong>Short Abstract: </strong>We have used new magnetotelluric data collected in the Curnamona Province and Delamerian Orogen to image electrical resistivity structures. Our resistivity model confirms crustal-scale conductive features mapped by AusLAMP models, i.e., the prominent Curnamona Province Conductor and the two Nackara Arc conductors, and resolves them in greater detail. The new model also reveals several apparently continuous arcuate conductors within the lower crust extending from the Eastern Nackara Arc Conductor to Broken Hill, and further into the Delamerian Orogen. In the west, these conductors coincide with the dominant structural grain of the Delamerian Orogen and are interpreted to represent ancient fluid pathways associated with major faults in the area. The eastern conductor diverts from the dominant structural grain in the Grasmere knee zone. The source of this conductor is enigmatic, although possibilities could include complex deformation as the Cambrian convergent margin was deformed in the Delamerian Orogeny, or younger events such as the emplacement of the late-Silurian Allambie Woolshed Granite. The conductive features provide new insights for understanding the geodynamic events and potential mineral systems associated with the transition from Proterozoic Australia in the west to the mostly Phanerozoic Tasmanides in the east. These conductivity anomalies may represent large-scale trans-crustal structures, which can place fundamental control on the spatial distribution and formation of mineral systems in the Curnamona Province and Delamerian Orogen.</div><div><br></div><div><strong>Citation: </strong>Jiang, W., Clark, A., Cheng, Y., Doublier, M., Hitchman, A. & Duan, J., 2024. Unveiling electrical resistivity structures along the undercover Delamerian Orogen, Southeast Australia. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://doi.org/10.26186/149232</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>

<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>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>