Geoscience Australia, in collaboration with state governments, will be carrying out airborne electromagnetic (AEM) surveys in eastern South Australia and western NSW and Victoria during 2022. The Australian Government’s Exploring for the Future program, led by Geoscience Australia, is committed to supporting a strong economy, resilient society and sustainable environment for the benefit of Australians. At its heart, the program is about contributing to a sustainable, long-term future for Australia through an improved understanding of the nation’s mineral, energy and groundwater resource potential <p>

This report contains new whole-rock and isotope geochemical data, associated sample metadata, an assessment of the data’s quality assurance, for 742 samples collected in and around the Curnamona and Delamerian provinces, across numerous drillcore sampling campaigns through 2021-23. The data can be downloaded via the Geoscience Australia EFTF portal (https://portal.ga.gov.au/persona/eftf) or in the files attached with this record (http://pid.geoscience.gov.au/dataset/ga/148651). Geochemical sampling in the Curnamona region straddles both South Australia and New South Wales. The objective of sampling was to obtain representative coverage (both stratigraphically and spatially) to support developing regional geochemical baselines (in conjunction with existing geochemistry). Thus, this sampling included both the Curnamona Province and the overlying basins (Eromanga Basin, Lake Eyre Basin). Whole-rock geochemistry is reported for 562 samples, with a subset of 13 samples analysed for Pb and Sr isotopes, and another subset of 36 samples analysed by thin section petrography (all presented herein). Geochemical sampling in the Delamerian region has focussed on available legacy drill core in South Australia, New South Wales and Victoria. The objective of sampling was to (systematically) constrain the geochemical character of magmatic rocks across the mainland extent of the Delamerian Orogen, as well as younger volcanics within the Delamerian Orogen and/or overlying cover. This geochemical sampling was conducted in conjunction with geochronology, mineral systems sampling and stratigraphic drilling (all components of the DCD project) to reinterpret the timing, character and fertility of the Delamerian Orogen. Whole-rock geochemistry is reported for 180 samples. Version 2.0 (published 28 November 2023) has added whole rock geochemistry for 22 new samples in the Delamerian region. The data products and report have been updated accordingly.

The Upper Darling Floodplain AEM Survey is part of the Exploring for the Future Program. This scientific research is being carried out to obtain data that will enhance understanding of the groundwater resources of the upper Darling River region. This information will support future water resource management decision-making in the region.

<div>Lithospheric and crustal architecture — the framework of major tectonic blocks, terranes and their boundaries — represents a fundamental first-order control on major geological systems, including the location of world-class mineral camps. Traditionally, lithospheric and crustal architecture are constrained using predominantly geophysical methods. However, Champion and Cassidy (2007) pioneered the use of regional Sm–Nd isotopic data from felsic igneous rocks to produce isotopic contour maps of the Yilgarn Craton, demonstrating the effectiveness of ‘isotopic mapping’, and the potential to map ‘time-constrained’ crustal architecture. Mole et al. (2013) demonstrated the association between lithospheric architecture and mineral systems, highlighting the potential of isotopic mapping as a greenfield area selection tool. Additional work, using Lu-Hf isotopes (Mole et al., 2014), demonstrated that the technique could constrain a range of temporal events via ‘time-slice mapping’, explaining how Ni-Cu-PGE mineralized komatiite systems migrated with the evolving lithospheric boundary of the Yilgarn Craton from 2.9 to 2.7 Ga. Similar studies have since been conducted in West Africa (Parra-Avila et al., 2018), Tibet (Hou et al., 2015), and Canada (Bjorkman, 2017; Mole et al., 2021; 2022). This work continues in Geoscience Australia’s $225 million Exploring for the Future program (2016-present). Isotopic mapping, which forms an integral part of a combined geology-geophysics-geochemistry approach, is currently being applied across southeast Australia, covering the eastern Gawler Craton, Delamerian Orogen, and western Lachlan Orogen, encompassing more than 3 Gyrs of Earth history with demonstrable potential for large mineral systems.</div><div> <b>Reference(s):</b></div><div> Bjorkman, K.E., 2017. 4D crust-mantle evolution of the Western Superior Craton: Implications for Archean granite-greenstone petrogenesis and geodynamics. University of Western Australia, PhD Thesis, 134 pp.</div><div> Champion, D.C. and Cassidy, K.F., 2007. An overview of the Yilgarn Craton and its crustal evolution. In: F.P. Bierlein and C.M. Knox-Robinson (Editors), Proceedings of Geoconferences (WA) Inc. Kalgoorlie '07 Conference. Geoscience Australia Record 2007/14, Kalgoorlie, Western Australia, pp. 8-13.</div><div> Hou, Z., Duan, L., Lu, Y., Zheng, Y., Zhu, D., Yang, Z., Yang, Z., Wang, B., Pei, Y., Zhao, Z. and McCuaig, T.C., 2015. Lithospheric architecture of the Lhasa terrane and its control on ore deposits in the Himalayan-Tibetan orogen. Economic Geology, 110(6): 1541-1575.</div><div> Mole, D.R., Fiorentini, M.L., Cassidy, K.F., Kirkland, C.L., Thebaud, N., McCuaig, T.C., Doublier, M.P., Duuring, P., Romano, S.S., Maas, R., Belousova, E.A., Barnes, S.J. and Miller, J., 2013. Crustal evolution, intra-cratonic architecture and the metallogeny of an Archaean craton. Geological Society, London, Special Publications, 393: pp. 23-80.</div><div> Mole, D.R., Fiorentini, M.L., Thebaud, N., Cassidy, K.F., McCuaig, T.C., Kirkland, C.L., Romano, S.S., Doublier, M.P., Belousova, E.A., Barnes, S.J. and Miller, J., 2014. Archean komatiite volcanism controlled by the evolution of early continents. Proceedings of the National Academy of Sciences, 111(28): 10083-10088.</div><div> Mole, D.R., Thurston, P.C., Marsh, J.H., Stern, R.A., Ayer, J.A., Martin, L.A.J. and Lu, Y., 2021. The formation of Neoarchean continental crust in the south-east Superior Craton by two distinct geodynamic processes. Precambrian Research, 356: 106104.</div><div> Mole, D.R., Frieman, B.M., Thurston, P.C., Marsh, J.H., Jørgensen, T.R.C., Stern, R.A., Martin, L.A.J., Lu, Y.J. and Gibson, H.L., 2022. Crustal architecture of the south-east Superior Craton and controls on mineral systems. Ore Geology Reviews, 148: 105017.</div><div> Parra-Avila, L.A., Belousova, E., Fiorentini, M.L., Eglinger, A., Block, S. and Miller, J., 2018. Zircon Hf and O-isotope constraints on the evolution of the Paleoproterozoic Baoulé-Mossi domain of the southern West African Craton. Precambrian Research, 306: 174-188.</div><div> This Abstract was submitted/presented to the Target 2023 Conference 28 July (https://6ias.org/target2023/)

<div>Near-surface magnetizations are ubiquitous across many areas of Australia and complicate reliable estimation of depth to deeper magnetizations. We have selected four test areas in which we use equivalent source dipoles to represent and quantify the near-surface magnetizations. We present a synthetic modelling study that demonstrates that field variations from the near-surface magnetizations substantially degrade estimation of depth to a magnetization 500 metres below the modelled sensor elevation and that these problems persist even for anomalies with significantly higher amplitudes. However, preferential attenuation of the fields from near surface magnetizations by upward continuation proved quite effective in improving estimation of depth to those magnetizations.</div> This Abstract was submitted/presented at the 2023 Australasian Exploration Geoscience Conference (AEGC) 13-18 March (https://2023.aegc.com.au/)

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. The Darling-Curnamona-Delamerian (DCD) 2D reflection seismic survey was acquired during May to August 2022 in the Delamerian Orogen, the Murray-Darling basin, the Curnamona Province, and the upper Darling River floodplain regions in South Australia, Victoria and New South Wales. This project is a collaboration between Geoscience Australia (GA), the Geological Survey of South Australia (GSSA), the Geological Survey of Victoria (GSV) and the Geological Survey of New South Wales (GSNSW) and was funded by the Australian Government’s Exploring for the Future (EFTF) program. The overall objective of the EFTF Darling-Curnamona-Delamerian project is to improve the understanding of mineral and groundwater resources of the Curnamona Province and Delamerian Orogen and overlying basin systems through acquisition and interpretation of new pre-competitive geoscience data sets. The total length of acquisition was 1256 km distributed over five deep crustal 2D reflection seismic lines 22GA-DL1 (446 km), 22GA-DL2 (249 km), 22GA-CD1 (287 km), 22GA-CD2 (178 km), 22GA-CD3 (39.5 km) to image deep crustal structures, and a high-resolution 2D reflection seismic line 22GA-UDF (56 km) to explore groundwater resources. The DL lines provide coverage of fundamental geophysical data over the Flinders Range, the Delamerian Province and the Murray-Darling basin region in eastern South Australia and Victoria. The CD lines extend through the Curnamona Province and into the Darling Basin. The UDF line will assist with refining the hydrogeological model, understanding groundwater dynamics, and locating areas better suited to groundwater bores for better quality groundwater in the upper Darling River floodplain area. The data processing was performed by a contractor under the supervision of Geoscience Australia. The five deep crustal lines (22GA-DL1,DL2,CD1,CD2,CD3) were processed with record lengths of 20 and 8 seconds, while the shallow high-resolution line (22GA-UDF) was processed at a 4 second length. This processing yielded DMO Stack, Post-Stack Time Migration, and Pre-Stack Time Migration products. <strong>Raw shot gathers and processed gathers for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 147423</strong>

As part of the program, the Darling-Curnamona-Delamerian project is investigating the groundwater potential of the upper Darling River floodplain, as well as the mineral and groundwater potential of parts of eastern South Australia, western New South Wales, western Victoria and western Tasmania. Communities, industries and the environment in the upper Darling River region have been impacted by recent droughts. During periods of low flow in the Darling River, groundwater has the potential to be an alternative water source for towns, agriculture and mining. The aim of the Upper Darling River Floodplain Groundwater study is to identify and better understand groundwater supplies beneath the floodplain and its surrounds. When combined with innovative water storage options, these groundwater resources could provide enhanced drought security and promote regional development. The study area covers ~31,000 km2 and includes a 450 km stretch of the Darling River floodplain from Wilcannia upstream to Bourke and Brewarrina.

The National Geochemical Survey of Australia (<a href="http://www.ga.gov.au/ngsa" title="NGSA website" target="_blank">NGSA</a>) is Australia’s only internally consistent, continental-scale <a href="http://dx.doi.org/10.11636/Record.2011.020" title="NGSA geochemical atlas and dataset" target="_blank">geochemical atlas and dataset</a>. The present dataset contains additional mineralogical data obtained on NGSA samples selected from the Darling-Curnamona-Delamerian (<a href="https://www.ga.gov.au/eftf/projects/darling-curnamona-delamerian" title="DCD website" target="_blank">DCD</a>) region of southeastern Australia for the first partial data release of the Heavy Mineral Map of Australia (HMMA) project. The HMMA, a collaborative project between Geoscience Australia and Curtin University underpinned by a pilot project establishing its feasibility, is part of the Australian Government-funded Exploring for the Future (<a href="https://www.ga.gov.au/eftf" title="EFTF website" target="_blank">EFTF</a>) program. The selected 223 NGSA sediment samples fall within the DCD polygon plus an approximately one-degree buffer. The samples were taken on average from 60 to 80 cm depth in floodplain landforms, dried and sieved to a 75-430 µm grainsize fraction, and the contained heavy minerals (HMs; i.e., those with a specific gravity >2.9 g/cm³) were separated by dense fluids and mounted on cylindrical epoxy mounts. After polishing and carbon-coating, the mounts were subjected to automated mineralogical analysis on a TESCAN® Integrated Mineral Analyzer (TIMA). Using scanning electron microscopy and backscatter electron imaging integrated with energy dispersive X-ray analysis, the TIMA identified over 140 different HMs in the DCD area. The dataset, consisting of over 29 million individual mineral grains identified, was quality controlled and validated by an expert team. The data released here can be visualised, explored and downloaded using an online, bespoke mineral network analysis tool (<a href="https://geoscienceaustralia.shinyapps.io/mna4hm/" title="MNA website" target="_blank">MNA</a>) built on a cloud-based platform. Accompanying this report are a data file of TIMA results and a mineralogy vocabulary file. When completed in 2023, it is hoped the HMMA project will positively impact mineral exploration and prospectivity modelling around Australia, as well as have other applications in earth and environmental sciences.

<div>This report presents the findings of a study conducted in the upper Darling River floodplain, aimed at improving optical and interferometric synthetic aperture radar (InSAR) remote sensing products for groundwater dependant vegetation (GDV) characterisation. The research was part of the Upper Darling Floodplain (UDF) groundwater study, funded by the Exploring for the Future program.</div><div>This work tests the suitability of two novel remote sensing methods for characterising ecosystems with a range of likely groundwater dependence: combined wetness and greenness indices derived from Landsat products available through Geoscience Australia’s Digital Earth Australia platform, and an InSAR derived index of vegetation structure (known as SARGDE), which has been so far tested only in northern Australia. In addition, the relationship between the Normalised Difference Vegetation Index (NDVI), a remotely sensed proxy for vegetation condition, and water availability from surface water flows, rainfall, and groundwater was tested for sites with a range of low to high likely groundwater dependence.&nbsp;</div><div>The key findings of this work, and potential implications, are:</div><div>• A multiple lines of evidence approach, drawing on persistence of wetness/greenness and vegetation structure, and correlation between inferred vegetation condition and groundwater levels, gives high confidence in the groundwater dependence of parts of the floodplain, particularly within the riparian zone. These indices require calibration with ground condition data to be applied in different regions, but a combined index could provide a high confidence measure of groundwater dependence.</div><div>• Combined greenness and wetness, SARGDE, and the relationship between NDVI and groundwater levels all showed areas classified as ‘moderate’ likelihood of groundwater dependence having signatures comparable to areas classified as high likelihood. This could address a shortcoming of the groundwater dependence classification methodology, which, when groundwater level information is missing, classifies some vegetation types as moderate.</div><div>• A combined index taking into account both greenness and wetness was able to better delineate vegetation types with a range of groundwater dependence previously not achievable using remote sensing products.&nbsp;</div><div>This work has provided improved methodology for applying remote sensing products to groundwater dependent vegetation characterisation in the study area. The methods are likely to be applicable to other regions with groundwater dependent vegetation. The results add to the evidence that it is necessary to better integrate surface and groundwater resources in water sharing plans at a basin scale. Further work is required to quantify the frequency and magnitude of flow events required to replenish alluvial groundwater sufficiently to maintain existing groundwater dependent ecosystems.&nbsp;&nbsp;</div><div><br></div><div><br></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 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>