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.

For more than half a century, seismic tomography has been used to map the volumetric structure of Earth’s interior, but only recent advances in computation have enabled the application of this technique at scale. Estimates of surface waves that travel between two seismic stations can be reconstructed from a stack of cross-correlations of continuous data recorded by seismometers. Here, we use data from the Exploring for the Future program AusArray deployment to extract this ambient noise signal of Rayleigh waves and use it to image mid- to upper-crustal structure between Tennant Creek and Mount Isa. Our aim was to establish a repeatable, semi-automatic workflow that can be extended to the entire Australian continent and beyond. Shear wave velocity models at 4, 6, 8 and 10 s periods are presented. A strong low-velocity anomaly (2.5 km/s) at a period of 4 s (~2–4 km depth) delineates the outline of the newly discovered, and prospective for hydrocarbons, Carrara Sub-basin. A near-vertical high-velocity anomaly (3.5 km/s) north of Mount Isa extends from the near surface down to ~12 km and merges with northeast-trending anomalies. These elongate features are likely to reflect compositional variations within the mid-crust associated with major structures inferred to be associated with base metal deposits. These outcomes demonstrate the utility of the ambient noise tomography method of imaging first-order features, which feed into resource potential assessments. <b>Citation: </b>Hejrani, B., Hassan, R., Gorbatov, A., Sambridge, M. Hawkins, R., Valentine, A., Czarnota, K. and Zhao, J., 2020. Ambient noise tomography of Australia: application to AusArray deployment. 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. <b>See eCat record <a href="https://dx.doi.org/10.26186/148676">#148676</a> for the updated version of the model package.</b>

SHRIMP U-Pb zircon and monazite geochronology of magmatic, metamorphic and sedimentary rocks sampled from an undercover region informally referred to as ‘East Tennant’, located approximately 200 km east of Tennant Creek, has redefined our knowledge of the geology of this region. These results establish strong temporal links with rocks in the Au-Cu-Bi mineralised Tennant Creek region (Warramunga Province) and the Paleoproterozoic Murphy Province, approximately 270 km to the northeast. Detrital zircon U-Pb analyses of two metasedimentary samples show maximum depositional ages of ca. 1875 Ma and detrital zircon age spectra similar to Warramunga Formation metasedimentary rocks in the Warramunga Province. Additionally, three extrusive rocks and an intermediate intrusive rock have magmatic crystallisation ages of 1858–1849 Ma, synchronous with magmatism in the Warramunga Province associated with the 1860–1845 Ma Tennant Event. Monazite U-Pb analyses of two samples of metapelites from the East Tennant region and Murphy Province record metamorphism at ca. 1845 Ma, which is also synchronous with magmatism associated with the Tennant Event. These new results suggest that the undercover East Tennant region could represent an extension of the Warramunga Province and therefore be prospective for Au-Cu-Bi mineralisation. <b>Citation:</b> Cross, A.J., Clark, A.D., Schofield, A. and Kositcin, N., 2020. New SHRIMP U-Pb zircon and monazite geochronology of the East Tennant region: a possible undercover extension of the Warramunga Province, Tennant Creek. 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.

Geological maps are one of the most important datasets used in resource exploration and management. Despite increasing demand for subsurface resources such as minerals, groundwater and energy, maps of the inferred subsurface geology of Australia and other continents have been limited to small regions or jurisdictions. Here, we present the first seamless semi-continental chronostratigraphic solid geology dataset of the North Australian Craton. This dataset comprises five time slices of stratigraphic units: Cenozoic, Mesozoic, Paleozoic, Neoproterozoic and pre-Neoproterozoic. Interpretation of covered units is based on available data: surface geology and solid geology maps, magnetic intensity and gravity images, drilling logs, reflection seismic profiles and airborne electromagnetic soundings. In total, 2008 units have been mapped, all linked to the Australian Stratigraphic Units Database. So far, these maps have led to a refinement of sedimentary basin and tectonic province outlines, lessened the risks of mineral exploration through Australia’s extensive superficial cover, disclosed geological units known to host resources elsewhere, and highlighted undercover regions with poor geological constraints. <b>Citation:</b> Stewart, A.J., Liu, S.F., Bonnardot, M.-A., Highet, L.M., Woods, M., Brown, C., Czarnota, K. and Connors, K., 2020. Seamless chronostratigraphic solid geology of the North Australian Craton. 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.

Crustal architecture places first-order controls on the distribution of mineral and energy resources. However, despite its importance, it is poorly constrained over much of northern Australia. Here, we present a full crustal interpretation of deep seismic reflection profile 18GA-KB1 that extends over 872 km from the Eo- to Mesoarchean Pilbara Craton to the Paleoproterozoic Aileron Province, transecting a range of stratigraphic and tectonic basement units, some of which are completely concealed by younger rocks. The seismic profile provides the first coherent image through this relatively poorly understood part of Australian geology and yields major new insights about the crustal architecture, geometry and definition of the different geological and seismic provinces and their boundaries. Key findings include the following: (1) The Pilbara Craton shows a three-component horizontal crustal layering, where the granite– greenstone East Pilbara Terrane is largely confined to the upper crust. (2) The Pilbara Craton has an extensive reworked margin, the Warrawagine Seismic Province, that thins towards the east, and underlies the western and central Rudall Province. (3) At the largest scale, the Rudall Province shows an approximately funnel-shaped geometry, with limited differences in seismic character between the various terranes. (4) The western Kidson Sub-basin is underlain by rocks of the Neoproterozoic Yeneena Basin and Rudall Province. (5) The central and eastern part of the Kidson Sub-basin rests on the coherent, relatively poorly structured Punmu Seismic Province, which is truncated by the steep, crustal-scale Lasseter Shear Zone, that marks the boundary to the Aileron Province to the east. <b>Citation:</b> Doublier, M.P., Johnson, S.P., Gessner, K., Howard, H., Chopping, R., Smithies, R.H., Martin, D.McB.,Kelsey, D.E., Haines, P.w., Hickman, A., Czarnota, K., Southby, C., Champion, D.C., Huston, D.L., Calvert, A.J., Kohanpour, F., Moro, P., Costelloe, R., Fomin, T. and Kennett, B.L.N., 2020. Basement architecture from the Pilbara Craton to the Aileron Province: new insights from deep seismic reflection line 18GA-KB1. 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.

Constraints on the morphology of the Moho are essential to establish reliable models of the subsurface and infer the evolution of the Australian crust. Reliable information on crustal thickness variations is important for thermal modelling and structural mapping, for both energy and mineral system studies. Here, we combine information from both passive seismic deployments and full-crustal reflection seismic profiling to produce a new representation of the character of the Moho in northern Australia. Data coverage has been dramatically improved by investments, under the Exploring for the Future program, in new deployments of passive seismic instrumentation and expansion of the network of reflection seismic profiles in the South Nicholson and Barkly regions. Using a new approach to combining results from different classes of seismic analysis, different spatial sampling associated with the various types of data have been taken into account. The resulting Moho surface reveals small-scale features not seen in previous models. New data reveal that some Moho discontinuities are clearly associated with known structures such as the Willowra Suture. Similar ~100 km wavelength undulations are visible in areas under cover that may indicate the presence of unknown major structures. Significant base metal mineral deposits appear to be localised along the edges of thicker crustal block. <b>Citation:</b> Gorbatov, A., Medlin, A., Kennett, B.L.N., Doublier, M.P., Czarnota, K., Fomin, T. and Henson, P., 2020. Moho variations in 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.

Metamorphic rocks provide a semi-continuous record of the thermal and barometric history of the crust, which is particularly useful in constraining paleo-crustal architectures, tectonic models and thereby mineral exploration. Given this importance, regional metamorphic studies in Australia have flourished during the past 30 years. However, the national metamorphic map of Australia has not been updated in more than 37 years. Here, we provide a snapshot of a national synthesis of all available quantitative metamorphic data, metamorphic chronology and metamorphic map patterns, integrated with stratigraphic, magmatic and kinematic datasets. Forty-eight orogenic cycles have been identified, spanning from the Paleoarchean to the Miocene, and most of permissible pressure (P) and temperature (T) space, indicating a wide variety of tectonic settings. This compilation provides a basis for establishing best-estimate working models for the metamorphic evolution of all orogenic systems, provinces and terranes. These insights are important in advancing the understanding of mineral systems in Australia.. <b>Citation:</b> Goscombe, B., Czarnota, K. Blewett, R.S. Skirrow, R.G. Everard, J.L. and Lawson, C., 2020. Metamorphic evolution of 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.

The Houtman Sub-basin geophysical modelling study is an integrated geological and geophysical interpretation of the GA-349 seismic survey. The key aims for the study were to improve the understanding of the crustal architecture of the Houtman Sub-basin and the distribution and thickness of magmatic rocks. The Houtman Sub-basin is a largely unexplored offshore depocentre in the northern Perth Basin on the western margin of Australia. It formed during two separate rifting episodes (Early- to Mid-Permian, Early Jurassic to Early Cretaceous) and may contain up to 19 km of sediment. The northern Houtman Sub-basin contains extensive breakup-related sill and dyke complexes, related to both the adjacent volcanic province of the Wallaby Plateau and the Wallaby Zenith Transform Margin (WZTM). New 2D seismic reflection data obtained in 2014/15 (GA-349) is being used to re-assess the petroleum prospectivity of this frontier basin to underpin the possible future release of exploration acreage. A full understanding of petroleum prospectivity requires a clear picture of sediment thickness, the nature of basement, and the distribution of magmatic rocks, all of which influence the maturation of hydrocarbons and ultimately prospectivity. Geoscience Australia seismic survey (GA-310) and marine sampling survey (GA-2476) conducted in 2008 and 2009 acquired a total of about 26,000 km of new gravity and magnetic data. This new gravity and magnetic data has been integrated and levelled with existing data, both offshore and onshore, to produce unified gravity and magnetic datasets for use in constraining regional tectonics, basin structure and petroleum prospectivity. The purpose of this study is to use potential field modelling to: a) validate seismic interpretation of crustal structure (in depth), including Moho depth and depth to top crystalline basement; b) model density variations within the sedimentary section; c) model density and magnetic susceptibility variations within basement with an interpretation of basement composition (if possible) and; d) investigate the depth, extent and thickness of intrabasinal magmatic rocks identified on seismic data.

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

In recent years there has been a considerable expansion of deployments of portable seismic stations across Australia, which have been analysed by receiver function or autocorrelation methods to extract estimates of Moho depth. An ongoing program of full-crustal reflection profiles has now provided more than 25,000 km of reflection transects that have been interpreted for Moho structure. The Moho dataset is further augmented by extensive marine reflection results. These new data sources have been combined with earlier refraction and receiver function results to provide full continental coverage, though some desert areas remain with limited sampling. The dense sampling of the Moho indicates the presence of rapid changes in Moho depth and so the Moho surface has been constructed using an approach that allows different weighting and spatial influence depending on the nature of the estimate. The inclusion of Moho results from gravity inversion with low weighting helps to resolve the continent-ocean transition and to provide additional control in the least sampled zones. The refined distribution indicates the presence of widespread smaller-scale variations in Moho structure. Strong lateral contrasts in crustal thickness remain, but some have become more subdued with improved sampling of critical areas. The main differences from earlier results lie in previously poorly sampled regions around the Lake Eyre Basin, where additional passive seismic results indicate somewhat thicker crust though still witha strong contrast in crustal thickness to the cratonic zone to the west. Appeared in Geophysical Journal International, January 2023