We present a 3‐D inversion of magnetotelluric data acquired along a 340‐km transect in Central Australia. The results are interpreted with a coincident deep crustal seismic reflection survey and magnetic inversion. The profile crosses three Paleoproterozoic to Mesoproterozoic basement provinces, the Davenport, Aileron, and Warumpi Provinces, which are overlain by remnants of the Neoproterozoic to Cambrian Centralian Surperbasin, the Georgina and Amadeus Basins, and the Irindina Province. The inversion shows conductors near the base of the Irindina Province that connect to moderately conductive pathways from 50‐km depth and to off‐profile conductors at shallower depths. The shallow conductors may reflect anisotropic resistivity and are interpreted as sulfide minerals in fractures and faults near the base of the Irindina Province. Beneath the Amadeus Basin, and in the Aileron Province, there are two conductors associated strong magnetic susceptibilities from inversions, suggesting they are caused by magnetic, conductive minerals such as magnetite or pyrrhotite. Beneath the Davenport Province, the inversion images a conductive layer from ∼15‐ to 40‐km depth that is associated with elevated magnetic susceptibility and high seismic reflectivity. The margins between the different basement provinces from previous seismic interpretations are evident in the resistivity model. The positioning and geometry of the southern margin of the crustal conductor beneath the Davenport Province supports the positioning of the south dipping Atuckera Fault as interpreted on the seismic data. Likewise, the interpreted north dipping margin between the Warumpi and Aileron Province is imaged as a transition from resistive to conductive crust, with a steeply north dipping geometry.

The Cloncurry Extension Magnetotelluric (MT) Survey is located north of the township of Cloncurry, in the Eastern Succession of the Mount Isa Province. The survey expands MT coverage to the north and west of the 2016 Cloncurry MT survey. The survey was funded out of the Queensland Government’s Strategic Resources Exploration Program, which aims to support discovery of mineral deposits in the Mount Isa Region. The survey area is predominantly covered by conductive sediments of the Carpentaria Basin. The cover thickness ranges from zero metres in the extreme south west of the survey, to over 345 meters in the north. Acquisition started in August 2019 and was completed in October 2020. The acquisition was managed under an collaborative framework agreement between the Geological Survey of Queensland and Geoscience Australia until April 2020, after which the GSQ took over management of the project. Zonge Engineering and Research Organization were responsible for field acquisition. Data were collected at 2 km station spacing on a regular grid with a target bandwidth of 0.0001 – 1000 s. Instruments were left recording for a minimum of 24 hours unless disturbed by animals. The low signal strength posed a significant impediment for acquiring data to 1000 s, even with the 24 hour deployments. Almost all sites have data to 100 s, with longer period data at numerous sites.

The Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) aims to collect long period magnetotelluric data on a half degree (~55 km) grid across the Australian continent. New data have recently been collected in New South Wales under a National Collaborative Framework agreement between Geoscience Australia and the Geological Survey of New South Wales. This data release contains a preferred resistivity model and associated inversion files for southeast Australia using data from AusLAMP Victoria (Duan & Kyi, 2018), far west NSW (Robertson et al. 2016) and from the rest of New South Wales up to August 2019 (Kyi et al 2020). The original work behind this model can be cited through the following paper which contains discussion on model development and its significance for tectonic evolution and metallogenic potential: Kirkby, A., Musgrave, R.J., Czarnota, K., Doublier, M.P., Duan, J., Cayley, R.A., Kyi, D., 2020. Lithospheric architecture of a Phanerozoic orogen from magnetotellurics: AusLAMP in the Tasmanides, southeast Australia. Tectonophysics, v. 793, 228560.

<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.</div><div><br></div><div>During February and March in 2023, Geoscience Australia undertook the Curnamona Cube Extension Magnetotelluric (MT) Survey in western New South Wales and eastern South Australia. The survey complements the University of Adelaide/AuScope Curnamona Cube MT survey by extending the coverage from the Curnamona Province into the Delamerian Orogen. Geoscience Australia contracted Quantec Geoscience Ltd. and its subcontractor Australian Geophysical Services to conduct the data acquisition and processing.&nbsp;Audio and broadband MT data was acquired at 99 sites on an approximately 12.5-25&nbsp;km grid with denser sites across known geological structures and along seismic lines acquired by Geoscience Australia in 2022 (L213 Darling-Curnamona-Delamerian (DCD) 2D Seismic Survey, eCAT # 147423). Instruments were set up to record five channels (three magnetic and two electric fields) for a minimum of 24 hours with a target bandwidth of 0.0001 – 1000 s. Processed data show good quality at a majority of the survey sites, except a few sites affected by environmental and cultural noise. The acquired data will be used to derive resistivity models, and to enhance the understanding of the geodynamics and mineral potential in the Curnamona Province and Delamerian Orogen.&nbsp;</div><div><br></div><div>This data release contains a field logistic report; processed data in EDI format containing spectra and site locations in shape file and .txt format. Time series data in ASCII format is available on request from clientservices@ga.gov.au - Quote eCAT#147904.</div><div><br></div><div>Geoscience Australia acknowledges the 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>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>

<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 AusLAMP-Victoria magnetotelluric survey was a collaborative project between the Geological Survey of Victoria and Geoscience Australia. Long period magnetotelluric data were acquired at 100 sites on a half degree grid spacing across Victoria in the south-east of Australia between December 2013 and September 2014. Some repeated sites were acquired in December 2017. Geoscience Australia managed the project and performed data acquisition, data processing, and data QA/QC. In this record, the field acquisition, data QA/QC, and data processing methodologies are discussed. A separate report will provide information on data analysis, data modelling/inversion, and data interpretation.

This OGC compliant service provides access to magnetotelluric data and associated products, which have been produced by Geoscience Australia’s Magnetotelluric Program. This program includes regional magnetotelluric projects and the Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP), a collaborative project between Geoscience Australia, the State and Northern Territory geological surveys, universities, and other research organisations. The data provided in this service comprise resistivity model depth sections and the locations of sites used in these studies.

<p>The Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) aims to collect long period magnetotelluric data on a half degree (~55 km) grid across the Australian continent. New datasets have been collected in Northern Australia, as part of Geoscience Australia’s Exploring for the Future (EFTF) program with in-kind contributions from the Northern Territory Geological Survey and the Queensland Geological Survey. <p>This release includes preliminary AusLAMP models in an under-explored region between Tennant Creek in the Northern Territory and Cloncurry in Queensland. Long period magnetotelluric data from 155 sites were used in this model. Magnetotelluric data acquisition in this region continues. The preliminary model results provide new insights to the lithospheric architecture and mineralisation in the region. There is a connection between conductive anomalies, large-scale lithospheric boundaries and the distribution of mineral deposits.

<div>The Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) is a collaborative national survey between federal government, state/territory governments and research organisations. The project aims to acquire long-period magnetotelluric (MT) data at half-degree spacing (~55&nbsp;km) across the Australian continent. AusLAMP started in 2013 and has completed about 1500 stations (~50% of total planned stations) to date. Over the last decade, regional-scale AusLAMP resistivity/conductivity models have been produced following data acquisition campaigns, but there is a strong demand for a single model. We produced a resistivity model from 1260 AusLAMP stations incorporating 85% of data acquired to date. The new AusLAMP resistivity model shows significant variations of resistivity at varying depths from a few kilometres to a couple of hundred kilometres in the crust and upper mantle. The model resolves the first-order resistivity structure of the Australian lithosphere across most parts of central and eastern Australia, including Tasmania. The resolved resistivity structures allow seamless interpretation across states and regions, broadly conform with identified major geological domains and crustal boundaries, and reveal significant variations within geological provinces, orogens and cratons. There are also 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 evidence aligns well with the conceptual model of mineral systems, that convecting mantle fluid and metal-rich magma can migrate into the crust through weak zones to form some ore deposits in the lithosphere. This new AusLAMP model demonstrates that long-period MT data are an important first-order reconnaissance dataset to resolve large-scale lithospheric architecture and provides a powerful tool with a bottom-up approach to highlight potential exploration areas, particularly in covered and under-explored regions. Presented at the 2024 Australian Society of Exploration Geophysicists (ASEG) Discover Symposium