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>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>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>

Short abstract: The Delamerian Orogen is spatially and temporally extensive, covering five states in central and eastern Australia. The orogen records the transition from Proterozoic Australia to the Phanerozoic Tasmanides, starting with rifting of the Rodinian supercontinent and transition to a passive margin from ca. 830 to 530 Ma, then developing as a convergent eastern Gondwanan margin from ca. 530 Ma that was terminated by the mid-to-late Cambrian Delamerian Orogeny. The orogen was later impacted by younger geodynamic events, particularly in the Ordovician-Silurian-Devonian. Due to the paucity of exposure, in particular in its central segment, and the complex cover sequences, significant parts of the Delamerian Orogen remain poorly documented. The orogen is also underexplored for resources despite demonstrated potential for magmatic-hydrothermal and other mineral systems. As part of the Exploring for the Future program, the Darling-Curnamona-Delamerian project is working to improve geodynamic framework and mineral systems knowledge through a range of activities including; analysis of legacy drill core, new stratigraphic drilling and major geophysical data acquisition campaigns (airborne electromagnetic, deep crustal seismic reflection, magnetotelluric). Significant first results reveal the existence of a corridor of Siluro-Devonian igneous rocks flanked by Cambrian igneous rocks within the Loch Lilly-Kars Belt, possibly related to an episode of rifting or extension, with potential for rift-related and magmatic-hydrothermal mineral systems of that age. <b>Citation:</b> Gilmore P.J., Roach I.C., Doublier M.P., Mole D.R., Cheng Y., Clark A.D. & Pitt L., 2023. From The Delamerian Orogen: exposing an undercover arc. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/148679

Communities and ecosystems along the Darling River face critical water shortages and water quality issues including high salinity and algal blooms due to a reliance on declining surface water flows, which are impacted by extraction and drought, exacerbated by increases in temperature driven by climate change. The Darling River, characterised by highly variable flows, is the primary water source for the region and our understanding of the spatial extent and character of lower salinity groundwater within the surrounding Darling Alluvium, which could provide an alternative water source, is limited. Scientific understanding of the highly variable groundwater-surface water system dynamics of the Darling River is also an integral part of the evidence base required to manage the water resources of the wider Murray-Darling Basin, which has experienced critical water shortages for domestic and agricultural consumptive use and serious ecological decline due to reduced flows. Other relevant groundwater systems in the study area include aquifers of the underlying Eromanga and Surat Basins in the north, aquifers of the Murray Basin in the south, and fractured rock aquifers of the Darling Basin in the south-central area. Understanding of connectivity between these systems and the groundwater systems within the Darling Alluvium, and surface water of the Darling River, is also limited. Here we present the findings of a desktop analysis combining previous research with new analysis on water level, hydrochemistry, and Airborne Electromagnetic depth sections. This integration suggests that basement geometry and hydrostratigraphy within the Darling Alluvium are key structural controls on surface-groundwater connectivity, and the occurrence of a saline groundwater system within the lower part of the alluvium which impacts the quality of surface water and shallow alluvial groundwater resources. Further data acquisition and integrated analysis are planned to test these relationships as part of the Upper Darling Floodplain project. <b>Citation:</b> Buckerfield S., McPherson A., Tan K. P., Kilgour P. & Buchanan S., 2022. From Upper Darling Floodplain groundwater resource assessment. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/146847

Australia remains underexplored or unexplored, boasting discovery potential in the mineral, groundwater, and energy resources hidden beneath the surface. These “greenfield” areas are key to Australia’s future prosperity and sustainability. Led by Geoscience Australia, Australia’s national government geoscience organisation, the Exploring for the Future program was a groundbreaking mission to map Australia’s mineral, energy, and groundwater systems in unparalleled scale and detail. The program has advanced our understanding of Australia’s untapped potential. Over the course of 8 years, the Exploring for the Future program provided a significant expansion of public, precompetitive geoscience data and information, equipping decision-makers with the knowledge and tools to tackle urgent challenges related to Australia’s resource prosperity, energy security, and groundwater supply.