<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>

Geoscience Australia has undertaken a regional seismic mapping study of the offshore Otway Basin extending across the explored inner basin to the frontier deep-water region. Seismic interpretation covers over 18,000 line-km of new and reprocessed data acquired in the 2020 Otway Basin seismic program, over 40,000 line-km of legacy 2D seismic data and GA’s new 2023 Otway 3D post-stack Mega Merge seismic dataset. This work provides a new perspective on regional structural architecture and basin evolution and has important implications for hydrocarbon prospectivity of this region. This seminar was two short talks centring on the Otway Basin. <u>Post-stack 3D merging to fast-track regional interpretation - offshore Otway Basin case study, presented by Merrie-Ellen Gunning</u> This case study was to produce a regularised and seamless 3D dataset of the highest possible quality, for the offshore Otway Basin, within two-months. The input migrated volumes varied by data extent, migration methodology, angle range and grid orientation. Fourteen input volumes totalling 8,092 km2 were post-stack merged and processed to produce a continuous and consistent volume, enabling more efficient and effective interpretation of the region. The surveys were regularised onto a common grid, optimised for structural trend, prior to survey matching. A mis-tie analysis algorithm, applied over a time window optimised for interpretation of key events, was used to derive corrections for timing, phase and amplitude, using a reference. This was followed by time-variant spectral and amplitude matching to improve continuity between volumes. Additional enhancements including noise removal and lateral amplitude scaling were also applied. The final merged volume offers significant uplift over the inputs, providing better imaging of structure and events and dramatically improving the efficiency and quality of interpretation. This enables rapid reconnaissance of the area by explorers. <u>Structural architecture of the offshore Otway Basin presented by Chris Nicholson</u> We present new basin-scale isochore maps that show the distribution of the Cretaceous depocentres. Maps for the Lower Cretaceous Crayfish and Eumeralla supersequences, together with those recently published for the Upper Cretaceous Shipwreck and Sherbrook Supersequences, completes the set of isochore maps for the main tectonostratigraphic basin intervals. Mapping of basement involved faults has revealed structural fabrics that have influenced depocentre development. The tectonostratigraphic development of depocentres and maps of deep crustal units delineate crustal thinning trends related to late Cretaceous extension phases. This work highlights the need to review and update structural elements. For example, the boundary between the Otway and Sorell basins is now geologically constrained. The refinements to the tectonostratigraphic evolution of the Otway Basin presented here have important implications for the distribution and potential maturity of petroleum systems, especially with regard to heat flow associated with crustal extension.

<div>As a planet without plate tectonics, Mars has a fundamentally different setting to Earth, and yet we observe many familiar structural features at the surface. Mars is also home to the largest volcanoes in the Solar System, which are the spectacular surface expressions of an enormous, long-lived magmatic system underlying the region known as Tharsis. The many surface structures in the Tharsis region are an important record of the geologic and volcanic history of Mars. They can provide insight into the timing and nature of volcanic systems, which is important to investigations of past climate and potential habitability. This talk will explore how volcanism has driven formation of the structures we see on the surface of Mars and how this can help us answer important questions about the evolution of the red planet. The work presented is based on Dr Claire Orlov's PhD research conducted at the University of Leeds, UK. </div>

Geoscience Australia is increasingly looking to quantify the impact and value of the scientific work that it undertakes. Quantifying impact helps to demonstrate the return on investment from expenditure of government funds in applying geoscience to Australia's most important challenges. Recent analysis has quantified the economic and social benefits arising from precompetitive geoscience under Exploring for the Future, an Australian Government program led by Geoscience Australia that is dedicated to exploring Australia's resource potential and boosting investment. This analysis used the Impact Pathway approach to collect data and information that provides evidence of project and program impacts. The analysis demonstrates that Exploring for the Future is likely to return hundreds of dollars to the Australian economy for every dollar spent on the program. Additional modelling using REMPLAN online analytical tools helps to quantify economic and employment benefits in regional Australia. These approaches to impact assessment are also being adopted across Geoscience Australia in areas ranging from satellite Earth observation to earthquake and tsunami hazard and risk.

For National Reconciliation Week, Geoscience Australia staff will present the progress of the organisation's first Innovate Reconciliation Action Plan as well as examples of engagement and collaboration with First Nations Australians.

Geoscience Australia's value to the nation, outlined in our overarching Strategy 2028, is through our science. However, the way that we apply our science to support a strong economy, resilient society and sustainable environment cannot be taken for granted. Our new Science Strategy 2028, to be launched by Geoscience Australia's Chief Scientist, Dr Steve Hill, during this event, will support Strategy 2028 in our mission to be the nation's trusted advisor on the geology and geography of Australia. It will provide strategic direction for developing and delivering the science that underpins our core business. Dr Hill will outline how our guiding Science Principles apply to our way of working -- not just the way in which we work as an organisation, but also in the way that we work with our partners in using science to create benefits for all Australians.

Exploring for the Future (EFTF) is a multiyear (2016–2024) initiative of the Australian Government, conducted by Geoscience Australia. This program aims to improve Australia’s desirability for industry investment in resource exploration of frontier regions across Australia. This paper will focus on the science impacts from the EFTF program in northern Australia derived from the acquisition and interpretation of seismic surveys, the drilling of the NDI Carrara 1 and also complementary scientific analysis and interpretation to determine the resource potential of the region. This work was undertaken in collaboration with the Northern Territory Geological Survey, the Queensland Geological Survey, AuScope and the MinEx CRC. These new data link the highly prospective resource rich areas of the McArthur Basin and Mt Isa Province via a continuous seismic traverse across central northern Australia. The Exploring for the Future program aims to further de-risk exploration within greenfield regions and position northern Australia for future exploration investment. [Carr] The Sherbrook Supersequence is the youngest of four Cretaceous supersequences in the Otway Basin and was deposited during a phase of crustal extension. This presentation shows how a basin-scale gross depositional environment (GDE) map for the Sherbrook SS was constructed, the significance of the map for the Austral 3 petroleum system, and why GDE mapping is important for pre-competitive basin studies at Geoscience Australia. [Abbott]

Finding new mineral deposits has never been an easy job. Increasing demand for a range of commodities, and depletion of existing deposits through mining, means that new frontiers need to be opened up for mineral exploration. These will largely be in regions where prospective basement rocks are concealed under cover. However, identification of these new frontiers is not a simple task, and exploration is challenging in areas where little is known about the geological context. This talk will outline how new datasets give us fresh eyes with which to view the mineral prospectivity of covered parts of Australia, and how integration of these data at a range of scales provides the framework in which to explore and discover new mineral provinces.

• Vertical datums are a foundational piece of the positioning puzzle that allows us make sense of height measurements - they make it possible to align height data by defining where all heights are zero. But when the vertical datum is unreliable, we lose perspective on which direction is down and this can cause strange things to happen. Water can appear to flow in the wrong direction or pool in unexpected places. • The Australian Height Datum (AHD) is the current, official, vertical datum in use in Australia. At 50 years old this year, it has stood the test of time well. But, it has a number of bumps and wrinkles (errors and distortions), relies on degrading physical infrastructure and was never intended to be used with modern positioning technology like GPS. The Australian Vertical Working Surface is a shiny new alternative vertical datum that doesn’t depend on any physical infrastructure, is free from the errors in the AHD and is designed to be directly compatible with GPS technology in the first instance.

Studies of three global sediment-hosted zinc provinces (Mt Isa, Australia; Northern Cordillera, Canada/USA; Irish Midlands, Ireland) indicate that deposits in all three provinces are associated with gradients in many geological parameters. These include lead isotopes, the depth of the lithosphere-asthenosphere boundary, upward-continued gravity and magnetotellurics data. These gradients are interpreted to mark major cratonic boundaries, or edges, that control the distribution of these deposits in space and in time. Studies of the Mt Isa Province indicate that regional alteration has caused extensive loss of zinc, copper and cobalt, potentially providing more than sufficient metal for the known deposits. Moreover, in some cases, metal loss corresponds to changes in rock properties, possibly enabling regional mapping of zones of metal loss using geophysical data.