Mineral deposits are the products of lithospheric-scale processes. Imaging the structure and composition of the lithosphere is therefore essential to better understand these systems, and to efficiently target mineral exploration. Seismic techniques have unique sensitivity to velocity variations in the lithosphere and mantle, and are therefore the primary means available for imaging these structures. Here, we present the first stage of Geoscience Australia's passive seismic imaging project (AusArray), developed in the Exploring for the Future program. This includes generation of compressional (P) and shear (S) body-wave tomographic imaging models. Our results, on a continental scale, are broadly consistent with a priori expectations for regional lithospheric structure and the results of previously published studies. However, we also demonstrate the ability to resolve detailed features of the Australian lithospheric mantle underneath the dense seismic deployments of AusArray. Contrasting P- and S-wave velocity trends within the Tennant Creek – Mount Isa region suggest that the lithospheric root may have undergone melt-related alteration. This complements other studies, which point towards high prospectivity for iron oxide–copper–gold mineralisation in the region. <b>Citation: </b>Haynes, M.W., Gorbatov, A., Hejrani, B., Hassan, R., Zhao, J., Zhang, F. and Reading, A.M., 2020. AusArray: imaging the lithospheric mantle using body-wave tomography. 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.

Lithospheric structure and composition have direct relevance for our understanding of mineral prospectivity. Aspects of the lithosphere can be imaged using geophysical inversion or analysed from exhumed samples at the surface of the Earth, but it is a challenge to ensure consistency between competing models and datasets. The LitMod platform provides a probabilistic inversion framework that uses geology as the fabric to unify multiple geophysical techniques and incorporates a priori geochemical information. Here, we present results from the first application of LitMod to the Australian continent. We demonstrate the ability to map important geophysical surfaces, and to differentiate between compositional (e.g. metasomatism) and thermal anomalies. We validate the posterior predictions from our inversion against independent studies, and this highlights the robustness of our results. Finally, we discuss recent technological advances in the implementation of LitMod3D_4INV, and how the model can be used to bring together multiple projects within the Exploring for the Future program to image the lithospheric mantle. The implications of this work extend beyond mineral prospectivity, and will ultimately inform our understanding of energy systems, groundwater and seismic hazard. <b>Citation:</b> Haynes, M.W., Fomin, I., Afonso, J.C., Gorbatov, A., Czarnota, K. and Salajegheh, F., 2020. Developing thermochemical models of Australia’s lithosphere. 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.

This service represents models of the structure and composition of the lithospheric mantle. The service currently delivers grids generated from modelling of the structure and composition of the lithospheric mantle at an Australian continental scale using the LitMod platform.

There is a growing recognition that lithospheric structure places first-order controls on the distribution of resources within the upper crust. While this structure is increasingly imaged using geophysical techniques, there is a paucity of geological constraints on its morphology and temporal evolution. Cenozoic intraplate volcanic rocks along Australia’s eastern seaboard provide a significant opportunity to constrain mantle conditions at the time of their emplacement and thereby benchmark geophysical constraints. This volcanic activity is subdivided into two types: age-progressive provinces generated by the passage of mantle plumes beneath the plate; and age-independent provinces, which may arise from edge-driven convection at a lithospheric step. In this study, we collected and analysed 78 igneous rock samples from both types of volcanoes across Queensland. We combined these analyses with previous studies to create and augment a comprehensive database of Australian Cenozoic volcanism. Geochemical modelling techniques were used to estimate mantle temperatures and lithospheric thicknesses beneath each province. Our results show that melting occurred at depths of 45–70 km across eastern Australia. Mantle temperatures are inferred to be ~50–100 °C higher beneath age-progressive provinces than beneath age-independent provinces. These results agree with geophysical observations used to aid resource assessments and indicate that upper mantle temperatures have varied over Cenozoic times. <b>Citation:</b> Ball, P.W., Czarnota, K., White, N.J. and Champion, D.C. 2020. Exploiting Cenozoic volcanic activity to quantify upper mantle structure beneath eastern Australia. 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.

Long-period magnetotelluric (MT) data allow geoscientists to investigate the link between mineralisation and lithospheric-scale features and processes. In particular, the highly conductive structures imaged by MT data appear to map the pathways of large-scale palaeo-fluid migration, the identification of which is an important element of several mineral system models. Given the importance of these data, governments and academia have united under the Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) to collect long-period MT data across the continent on a ~55 km-spaced grid. Here, we use AusLAMP data to demonstrate the MT method as a regional-scale tool to identify and select prospective areas for mineral exploration undercover. We focus on the region between Tennant Creek in the Northern Territory and east of Mount Isa in Queensland. Our results image major conductive structures up to 150 km deep in the lithosphere, such as the Carpentaria Conductivity Anomaly east of Mount Isa. This anomaly is a significant lithospheric-scale conductivity structure that shows spatial correlations with a major suture zone and known iron oxide–copper–gold deposits. Our results also identify similar features in several under-explored areas that are now considered to be prospective for mineral discovery. These observations provide a powerful means of selecting frontier regions for mineral exploration undercover.. <b>Citation:</b> Duan, J., Kyi, D., Jiang, W. and Costelloe, M., 2020. AusLAMP: imaging the Australian lithosphere for resource potential, an example from northern Australia. 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.

This service represents models of the structure and composition of the lithospheric mantle. The service currently delivers grids generated from modelling of the structure and composition of the lithospheric mantle at an Australian continental scale using the LitMod platform.

The Exploring for the Future program Virtual Roadshow was held on 7 July and 14-17 July 2020. The Minerals session of the roadshow was held on 14 July 2020 and consisted of the following presentations: Introduction - Richard Blewett Preamble - Karol Kzarnota Surface & Basins or Cover - Marie-Aude Bonnardot Crust - Kathryn Waltenberg Mantle - Marcus Haynes Zinc on the edge: New insights into sediment-hosted base metals mineral system - David Huston Scale reduction targeting for Iron-Oxide-Copper-Gold in Tennant Creek and Mt Isa - Anthony Schofield and Andrew Clark Economic Fairways and Wrap-up - Karol Czarnota

Water, energy and mineral resources are vital for Australia’s economic prosperity and sustainable development. However, continued supply of these resources cannot be taken for granted. It is widely accepted that the frontier of exploration now lies beneath the Earth’s surface, making characterisation of the subsurface a unifying challenge. Between 2016 and 2020, the $100.5 million Exploring for the Future program focused on addressing this challenge across northern Australia in order to better define resource potential and boost investment. The program applied a multiscale systems approach to resource assessment based on characterisation of the Australian plate from the surface down to its base, underpinned by methodological advances. The unprecedented scale and diversity of new data collected have resulted in many world-first achievements and breakthrough insights through integrated systems science. Through this multi-agency effort, new continental-scale datasets are emerging to further enhance Australia’s world-leading coverage. The program has identified prospective regions for a wide range of resources and pioneered approaches to exploration undercover that can be applied elsewhere. The outcomes so far include extensive tenement uptake for minerals and energy exploration in covered terranes, and development of informed land-management policy. Here, we summarise the key scientific achievements of the program by reviewing the main themes and interrelationships of 62 contributions, which together constitute the Exploring for the Future: extended abstracts volume. <b>Citation:</b> Czarnota, K., Roach, I.C., Abbott, S.T., Haynes, M.W., Kositcin, N., Ray, A. and Slatter, E., 2020. Exploring for the Future: advancing the search for groundwater, energy and mineral resources. 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.

This service represents models of the structure and composition of the lithospheric mantle. The service currently delivers grids generated from modelling of the structure and composition of the lithospheric mantle at an Australian continental scale using the LitMod platform.

This service represents models of the structure and composition of the lithospheric mantle. The service currently delivers grids generated from modelling of the structure and composition of the lithospheric mantle at an Australian continental scale using the LitMod platform.