The Officer Basin in South Australia and Western Australia is the focus of a regional stratigraphic study being undertaken by the Exploring for the Future (EFTF) program, an Australian Government initiative dedicated to increasing investment in resource exploration in Australia. This data release provides data from new digital photography, X-ray Computerised Tomography (XCT) scanning, unconfined compressive strength (UCS) and tensile strength, laboratory ultrasonic testing, and gas porosity and permeability experiments for 41 samples from five legacy stratigraphic and petroleum exploration boreholes drilled within the Officer Basin. Additional low permeability tests were undertaken on select samples that were identified as being ultra-tight (permeability <1 µD). These samples were analysed at CSIRO Geomechanics and Geophysics Laboratory in Perth during April to June 2021.

This study was commissioned by Geoscience Australia (GA) to produce a report on seal capacity of select samples from wells in the Officer Basin of Western Australia and South Australia. Plugs were taken from the Giles-1, Yowalga-3, Vines-1 and Birksgate-1 wells and analysed via mercury injection capillary pressure testing. Results demonstrate that the analysed samples are capable of sealing very large columns of both methane and carbon dioxide.

<div>Geoscience Australia’s Exploring for the Future (EFTF) 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>This record contains geological notes on layered geology interpretation of twenty-nine 1:250 000 Sheet areas in eastern Queensland. The geology maps generated as part of this work were not released as a separate product but incorporated into the national layered geology product of Sanchez et al. (2024). There are five layers interpreted; pre-Neoproterozoic, Neoproterozoic, Paleozoic, Mesozoic and Cenozoic. Preparation of these layers involved figuratively peeling off successively older rocks and identifying and outlining the rocks thereby revealed. The notes provide comments on the rocks comprising each layer, and explain how the identity of the revealed rocks was arrived at where this is not obvious. The Cenozoic time slice was extracted from the 1:1 000 000 scale outcrop geology (Raymond et al., 2012) after removing the surficial deposits and without further interpretation.&nbsp;</div>

Brumbys 1 was an appraisal well drilled and cored through Brumbys Fault at the CO2CRC Otway International Test Centre in 2018. The Otway Project is located in South West Victoria, on private farming property approximately 35 km southeast of Warrnambool and approximately 10 km northwest of the town of Peterborough. Total measured depth was 126.6 m (80 degrees). Sonic drilling enabled excellent core recovery and the borehole was completed as a groundwater monitoring well. Brumbys 1 cores through the upper Hesse Clay, Port Campbell Limestone and extends into the Gellibrand Marl. This dataset compiles the extensive analysis undertaken on the core. Analysis includes: Core log; Foram Analysis; Paleodepth; % Carbonate (CaCO3); X-Ray Fluorescence Spectrometry (XRF); Inductively Coupled Plasma Mass Spectrometry (ICP-MS); X-Ray Diffraction (XRD); Grain Size; Density; Surface Area Analysis (SAA); Gamma. Samples were taken at approximately 1-2 m intervals.

<div>Geoscience Australia’s Exploring for the Future (EFTF) 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.&nbsp;</div><div><br></div><div>The Layered Geology of Australia 1:1 000 000 scale dataset (2024 edition) is a seamless national coverage of Australia’s surface and subsurface geology.&nbsp;Geology concealed under younger cover units are mapped by effectively removing the overlying stratigraphy (Liu et al., 2015). This dataset is a layered product and comprises five chronostratigraphic time slices: Cenozoic, Mesozoic, Paleozoic, Neoproterozoic, and Pre-Neoproterozoic. As an example, the Mesozoic time slice (or layer) shows Mesozoic age geology that would be present if all Cenozoic units were removed. The Pre-Neoproterozoic time slice shows what would be visible if all Neoproterozoic, Paleozoic, Mesozoic, and Cenozoic units were removed. In general, a top down approach has been taken so that only the uppermost units for each era are shown. However, in areas of relative geological complexity and where that detail was available in the source data, some units may show overlap. In these instances, the units are ordered from oldest (base) to youngest (top). The Cenozoic time slice layer for the national dataset was extracted from Raymond et al., 2012. Surface Geology of Australia, 1:1 000 000 scale, 2012 edition. Geoscience Australia, Canberra, and retains the data schema of that dataset. For that layer’s metadata, refer to https://dx.doi.org/10.26186/74855.</div><div><br></div><div>Geological units are represented as polygon and line geometries and are attributed with information regarding stratigraphic nomenclature and hierarchy, age, and lithology. All stratigraphic information populated in the dataset is derived from the Australian Stratigraphic Units Database. The dataset also contains a layer for structural features such as faults and shears.</div>

During 2021–2024 Geoscience Australia conducted regional seismic mapping across the offshore Otway Basin that extended into the frontier deep-water region. This work was part of a broader pre-competitive study undertaken in support of petroleum exploration. Seismic horizons and faults were interpreted on three regional data sets, including: over 18 000 line-km of new and reprocessed data compiled for the 2020 offshore Otway Basin seismic program; over 40 000 line-km of legacy 2D seismic data; and the Otway 3D Megamerge dataset. This digital dataset (publication date 9 September 2024) updates and replaces a previously released dataset (publication date 16 May 2022). This updated dataset includes 8 surface grids and 11 isochron grids generated from the following seismic horizons (in ascending stratigraphic order); MOHO (Mohorovičić discontinuity), TLLCC (top laminated lower continental crust), Base (base Crayfish Supersequence), EC2 (base Eumeralla Supersequence), LC1 (base Shipwreck Supersequence), LC1.2 (base LC1.2 Sequence), LC2 (base Sherbrook Supersequence), and T1 (base Wangerrip Supersequence). Fault polygons created for all surfaces (except for MOHO, TLLCC, and LC1.2) are also included in the dataset. Maps generated from the dataset depict deep-water Cretaceous depocentres, and trends in crustal thinning and rifting during the Cretaceous. This revised dataset has underpinned updates to regional structural elements, including a revision of the boundary between the Otway and Sorell basins.

<div>The recent Musgrave Palaeovalley Project set out to map the extent and characterise the palaeovalley architecture of several of these Cenozoic features that overlie the Musgrave Province in central Australia. To effectively model the palaeovalley architecture of these features we collected approximately 20 000 line km of new Airborne Electromagnetics (AEM) and combined it with an array of existing AEM datasets, including AusAEM and high resolution mineral exploration surveys. These older surveys were reprocessed and reinverted to produce a consistent and reliable interpretation throughout. Utilising surface geology and lithology logs to constrain this data set, we mapped the interface between Cenozoic sediments and underlying pre-Cenozoic rocks, producing a continuous three-dimensional model of this boundary throughout the study area.</div><div><br></div><div>Our three-dimensional model enhances the understanding of the West Musgrave palaeovalley system, redefining palaeovalley extents, revealing previously unmapped palaeovalleys and identifying areas with significant accumulations of Cenozoic sediments. This methodology was also extremely useful for investigating palaeovalley geometry, revealing southerly flowpaths consistent with regional expectations but also highlighting areas of palaeovalley deformation where neo tectonic forces have acted to alter historical flow regimes. This deformation is likely to cause groundwater compartmentalisation, mounding or connect different aquifer units. Presented at the 2024 Australian Society of Exploration Geophysicists (ASEG) Discover Symposium

As part of Geoscience Australia's Exploring for the Future program, the East Tennant region, which is centred on the Barkly Roadhouse in the Northern Territory, was identified as having favourable geological and geophysical indicators of mineral systems potential. Potentially prospective stratigraphy in the East Tennant region is completely concealed beneath Mesoproterozoic to Quaternary cover sequences. Prior to 2020 basement rocks in the East Tennant region were only known from a handful of legacy boreholes, supported by geophysical interpretation. In order to test geophysical interpretations and obtain additional samples of basement rocks for detailed analysis, a stratigraphic drilling campaign was undertaken in the East Tennant region as part of the MinEx CRC’s National Drilling Initiative. Ten stratigraphic boreholes were drilled through the cover sequences and into basement for a total of nearly 4000 m, including over 1500 m of diamond cored basement rocks to be used for scientific purposes. Inorganic geochemical samples from East Tennant National Drilling Initiative boreholes were taken to characterise cover and basement rocks intersected during drilling. Two sampling approaches were implemented based on the rocks intersected: 1) Borehole NDIBK04 contained localised sulphide mineralisation and elevated concentrations of several economically-significant elements in portable X-ray fluorescence data. In order to understand the geochemical variability and distribution of elements important for mineral system characterisation, the entire basement interval was sampled at nominal one metre intervals. This spacing was reduced to between 0.5 and 0.25 m from 237 m to 263 m to better understand a more intense zone of mineralisation, and 2) Samples from boreholes NDIBK01, NDIBK02, NDIBK03, NDIBK05, NDIBK06, NDIBK07, NDIBK08, NDIBK09 and NDIBK10 were selected to capture lithological and geochemical variability to establish bulk rock geochemical compositions for further interpretation. Attempts were made to sample representative, lithologically consistent intervals. A total of 402 samples were selected for analysis. Sample preparation was completed at Geoscience Australia and Bureau Veritas, with all analyses performed by Bureau Veritas in Perth. All samples were submitted for X-ray fluorescence (XRF), laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), FeO determination, and loss on ignition (LOI). Samples from borehole NDIBK04 also underwent total combustion C and S, and Pb collection fire assay by ICP-MS for determination of Au, Pt and Pd concentrations. This data release presents inorganic geochemistry data acquired on rock samples from the ten East Tennant National Drilling Initiative boreholes.

<div>The groundwater and surface water systems associated with the Upper Darling River Floodplain (UDF) in arid northwest New South Wales form part of the Murray-Darling Basin drainage system, which hosts 40% of Australia’s agricultural production. Increasing water use demands and a changing regional climate are affecting hydrological systems, and consequently impacting the quality and quantity of water availability to communities, industries and the environment.</div><div>As part of the Australian Government’s Exploring for the Future program, the UDF project is working in collaboration with State partners to collect and integrate new data and information with existing hydrogeological knowledge. The goal is to provide analyses and products that assist water managers to increase water security in the region, with a focus on groundwater resources. </div><div>As part of this project we are assessing the occurrence of, and geological controls on, potable water resources within the Darling Alluvium (DA), which comprises unconsolidated sediments (<140 m thick) associated with the modern and paleo-Darling River. The DA’s relationship to the underlying Eromanga, Surat (Great Artesian Basin) and Murray basins is also important, particularly in the context of potential groundwater sources or sinks, and connection between low and high quality groundwater resources. At least one major fault system is known to influence groundwater flow paths and control groundwater-surface water interaction.</div><div>Data collection across the project area has commenced, with an airborne electromagnetic (AEM) survey already complete, and new geophysical, hydrochemical and hydrodynamic data being acquired. Preliminary interpretation of the new AEM data in conjunction with existing geological and hydrogeological information has already revealed the major paths and geometries of the paleo-Darling River, given important insights into fault controls on groundwater flow paths, and shown variation in the thickness, distribution and character of the DA, which has direct implications for groundwater–surface water connectivity.</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 increasing demand for mineral, energy and groundwater resources to support sustainable development and achieve net zero carbon targets in the face of climate change necessitates a deeper understanding of Earth’s resources and geological processes. Traditional 2D geological maps, while valuable for synthesizing and communicating geoscientific information, are limited in depicting the full extent and depth of geological units, which is crucial for effective resource exploration and management. Here, we present the Layered Geological Map of Australia (LGMA) dataset, the world’s first layered geological model at the continental scale. It integrates diverse geological, geochemical and geophysical datasets to create a comprehensive, machine-readable 3D geological framework spanning Australia's surface and subsurface. The dataset contains approximately 185,000 polygons representing the extent of around 7,600 geological units grouped into five chronostratigraphic layers corresponding to major Era boundaries (Cenozoic, Mesozoic, Paleozoic, Neoproterozoic and pre-Neoproterozoic). Standardised and consistent chrono-lithostratigraphy for each geological unit were captured through the Australian Stratigraphic Units Database (ASUD) and linked to the layered geology map to provide an attribute-rich dataset that can be queried and visualised in Geographic Information System (GIS) software or 3D modelling packages. The LGMA represents a significant advancement in Australian geoscience towards a 3D geological model of Australia, offering a foundational resource for academia, government, and industry alike.&nbsp;</div><div><br></div><div><strong>Citation: </strong>Sanchez, G., Liu, S., Steward, A.J., Bonnardot, M.A., Beyer, E.E., Czarnota, K., Highet, L.M., Woods, M., Brown, C.E., Clark, A., Connors, K., Wong, S. &amp; Cloutier, J., 2024. First continental layered geological map of Australia. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://doi.org/10.26186/149391</div>