From 1 - 10 / 46
  • <div>This study is part of the Mineral Potential Assessment (MPA) module of Geoscience Australia's Darling-Curnamona-Delamerian (DCD) project, a deep-dive project within the Exploring for the Future Program (EFTF) 2020-2024. An objective of the DCD project is to further the understanding of the geological architecture of the Delamerian Orogen into a cohesive framework enable a regional mineral potential assessment of this under-explored and mostly under cover Orogen. The MPA module is one of eight modules under the umbrella of the DCD project. To facilitate assessment of the mineral potential of the project area, the mineral potential assessment study has 3 key scientific objectives: (1) Defining the characteristics of the mineral systems / prospects. (2)&nbsp;&nbsp;Evaluating the temporal framework of the formation of mineral systems / prospects; and (3) Understanding the regional magma fertility. This study delivers Objective 1, i.e., outlining the principle geological and metallogenic characteristics of reported mineral prospects in the project area.&nbsp;</div><div><br></div><div>Legacy drill cores best demonstrating metallogenic features of different mineral system types at key prospects across the project area were selected for viewing and sampling following review of historical exploration reports and assay results. Four sets of data are included in the appendices of this report: (1)&nbsp;&nbsp;HyLogger spectral images of 20 drill holes of 8 prospects in New South Wales. (2)&nbsp;&nbsp;143 high-resolution scan files of legacy drill core samples across the project area. (3)&nbsp;&nbsp;16 microscopic images of thin sections for 4 prospects of the Loch Lilly-Kars Belt, New South Wales. (4)&nbsp;&nbsp;53 Backscattered Electron (BSE) images and 53 Advanced Mineral Identification and Characterization System (AMICS) high-resolution mineral maps of 53 samples from 18 prospects across the whole Delamerian Margin.&nbsp;</div><div><br></div><div>Metallogenic characteristics of samples from four different mineral deposit types were studied, along deposits of uncertain affiliation (referred here as undefined systems), including (1) Porphyry-epithermal mineral systems. (2)&nbsp;&nbsp;Volcanic hosted massive sulfide (VHMS) mineral systems. (3)&nbsp;&nbsp;Orogenic gold mineral systems. (4)&nbsp;&nbsp;Mafic-ultramafic Cu-Ni-PGE mineral systems. (5)&nbsp;&nbsp;Metallogenetically undefined systems. Detailed metallogenic characteristics of the samples from 22 key prospects in Delamerian Orogen are documented in this report.&nbsp;&nbsp;</div><div><br></div><div>This is the first systemic study on the essential metallogenic characteristics of the mineral systems in Delamerian. The characterisations outlined in this report are foundational for understanding the regional metallogenesis and assessing the potential of multiple types of mineral systems in the Delamerian Belt, which should be useful in both academic and the mineral exploration sector.</div><div><br></div><div>The high-resolution BSE and AMICS mineral maps are available at Geoscience Australia. Please reach out to the senior author of this GA Record, Dr. Yanbo Cheng (Yanbo.cheng@ga.gov.au). </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>

  • 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

  • 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>

  • <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/)

  • This service delivers grids for the depth below ground level of base of Cenozoic, Mesozoic, Paleozoic and Neoproterozoic surfaces in the Darling-Curnamona-Delamerian (DCD) region. The surfaces are a product of a layered cover model characterising depth and thickness of key stratigraphic sequences. The model was generated using Loop 3D (https://loop3d.org), an open-source 3D probabilistic geological and geophysical modelling platform, using a selection of depth estimates from AEM interpretation, stratigraphic boreholes and interpretation of depth of magnetisation as inputs.

  • <div>The Curnamona Province and overlying basins (herein referred to as the Broken Hill region) contain many discrete groundwater systems. These include sedimentary aquifers of the Lake Eyre Basin, Eromanga Basin, Darling Basin and Arrowie Basin, as well as fractured rock aquifers of the Adelaide Superbasin and Curnamona Province. However, there is little known about the hydrogeology or hydrogeochemistry of these aquifers in the Broken Hill region. Given the semi-arid climate in this region, understanding these groundwater systems can better support sustainable use of the groundwater for agriculture, mining and potable water supplies.</div><div>&nbsp;</div><div>Aquifer attribution provides a fundamental starting point for any hydrogeological study. We will present recently released hydrogeochemical data for the Broken Hill region, and our subsequent process for assessing and attributing hydrostratigraphy to the samples. </div><div>The Broken Hill Groundwater Geochemistry dataset (BHGG) was recently released in its entirety (Caritat et al. 2022 http://dx.doi.org/10.11636/Record.2022.020). It contains a compilation of archival CRC LEME hydrochemistry data that was collected as part of several projects from 1999 to 2005. This high-quality dataset contains 275 groundwater samples and includes a comprehensive suite of majors, minors, trace elements and stable isotopes (δ34S, δ18O, δ2H, δ13C, 87Sr/86Sr, 208/207/206Pb/204Pb). </div><div> At the time of collection, some key bore metadata (e.g. bore depths, screen and aquifer information) were missing from the original data compilations and these metadata are crucial for any hydrogeological analysis and interpretation. Therefore, as part of the new BHGG data release we have developed a robust and consistent approach to add bore information and aquifer attribution, value-adding to the original BHGG chemical and isotopic data. This workflow utilises a combination of State databases, reports, field notes, drillhole compilations and geological maps, but still relied on local hydrological expertise to make decisions when encountering incomplete or conflicting information (which is reflected by a confidence rating on the attribution). </div><div> The resulting BHGG product has supported re-assessment of the key hydrogeological and geochemical knowledge gaps in each groundwater system. An overview of knowledge gaps and the new sampling program being undertaken will be included in the presentation. &nbsp;</div><div><br></div>This Abstract was submitted/presented to the 2022 Australasian Groundwater Conference 21-23 November (https://agc2022.com.au/)

  • <div>The Darling-Curnamona-Delamerian (DCD) project focused on the covered portion of the Delamerian orogen, situated in the south-eastern mainland states of Australia.&nbsp;The aims of the project were to develop a greater understanding of the geodynamic history of the Delamerian Orogen, characterise known magmatic-hydrothermal mineral systems, and assess mineral potential for a suite of minerals including copper (Cu), gold (Au), and nickel (Ni), and critical minerals like platinum-group elements (PGEs) and rare-earth elements (REEs). </div><div>Here, we collate whole rock geochemistry data from new and legacy samples of mafic to intermediate magmatic rocks of the Loch Lilly-Kars Belt in order to determine the likely source of these magmas and constrain the prevailing tectonic setting during their emplacement. We apply multi-elemental diagrams and various elemental discrimination diagrams to characterise various groups of magmatic rocks in these belts, taking into account their geographic affinity and new geochronological data (e.g. Mole et al., 2023; Mole et al., 2024). The geochemical characteristics of these groups and the implications for the tectonic setting into which they were emplaced are discussed. Comparisons are made with potentially similar magmatic rocks of the&nbsp;Koonenberry Belt and Grampians-Stavely Zone. Results from this study have significant implications for the tectonic setting in which the Loch Lilly-Kars Belt developed, and hence also the mineral potential of the Belt. </div><div> </div>

  • <div><strong>Output Type: </strong>Exploring for the Future Extended Abstract</div><div><br></div><div><strong>Short Abstract: </strong>Communities and ecosystems along the Darling-Baaka River have been impacted by critical water shortages and water quality issues including high salinity, algal blooms, and fish kills due to declining surface water flows. The river is characterised by naturally highly variable flows and is the primary water source for the region, but extraction and a meteorological drying trend associated with climate change have caused declines in discharge of 53–73% since the advent of post-settlement agriculture and industry. Understanding of the spatial extent, quality, and useability of lower salinity groundwater within the surrounding Darling Alluvium, which could provide an alternative and potentially more sustainable water source, was previously limited. Here we present the findings of an integrated study combining modelled ground and airborne geophysical data, groundwater and surface water levels, hydrochemistry, lithology, and remote sensing data to delineate groundwater systems and understand the geological and hydrological controls on their occurrence. The resolution and breadth of datasets acquired and collated permit mapping of the key factors controlling occurrence and quality of groundwater aquifers, namely basement topography and hydrostratigraphy, groundwater-surface water dynamics, and inter-aquifer connectivity. On this basis the study area can be sub-divided into regions with distinctive aquifer distribution and quality, recharge mechanisms, and pressure gradients between aquifers. We also showed that the groundwater levels in the unconfined aquifer have declined, an expected outcome of the decline in discharge in the Darling-Baaka River which forms the primary recharge mechanism for the alluvial aquifers. These outputs have direct implications for key management questions including location and quantity of potentially useable groundwater, risk of saline groundwater up-coning or discharging to the river, and likelihood of groundwater extraction impacting river flows and groundwater dependent ecosystems.&nbsp;</div><div><br></div><div><strong>Citation: </strong>Buckerfield, S., McPherson, A., Tan, K.P., Walsh, C., Buchanan, S., Kilgour, P., Suckow, A., Raiber, M., Symington, N. & Pincus, J., 2024. Groundwater systems of the Upper Darling-Baaka River Floodplain. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts. Geoscience Australia, Canberra. https://doi.org/10.26186/149718</div>

  • <div>Defining and characterising groundwater aquifers usually depends on the availability of data necessary to represent its spatial extent and hydrogeological properties, such as lithological information and aquifer pump test data.&nbsp;In regions where such data is of limited availability and/or variable quality, the characterisation of aquifers for the purposes of water resource assessment and management can be problematic.&nbsp;The Upper Darling River Floodplain region of western New South Wales, Australia, is an area where communities, natural ecosystems and cultural values are dependent on both surface and groundwater resources.&nbsp;Owing to a relative paucity of detailed geological and hydrogeological data across the region we apply two non-invasive geophysical techniques—airborne electromagnetics and surface magnetic resonance—to assist in mapping and characterising the regional alluvial aquifer system.&nbsp;The combination of these techniques in conjunction with limited groundwater quality data helps define an approximate extent for the low salinity alluvial aquifer in a key part of the Darling River valley system and provides insights into the relative water content and its variation within the aquifer materials.&nbsp;This work demonstrates the utility of these key geophysical data in developing a preliminary understanding of aquifer geometry and heterogeneity, thereby helping to prioritise targets for follow-up hydrogeological investigation. Presented at the 2024 Australian Society of Exploration Geophysicists (ASEG) Discover Symposium