Geoscience Australia’s regional assessments and basin inventories are investigating Australia’s groundwater systems to improve knowledge of the nation’s groundwater potential under the Exploring for the Future (EFTF) Program and Geoscience Australia’s Strategy 2028. Where applicable, integrated basin analysis workflows are being used to build geological architecture advancing our understanding of hydrostratigraphic units and tie them to a nationally consistent chronostratigraphic framework. Here we focus on the Great Artesian Basin (GAB) and overlying Lake Eyre Basin (LEB), where groundwater is vital for pastoral, agricultural and extractive industries, community water supplies, as well as supporting indigenous cultural values and sustaining a range of groundwater dependent ecosystems such as springs and vegetation communities. Geoscience Australia continued to revise the chronostratigraphic framework and hydrostratigraphy for the GAB infilling key data and knowledge gaps from previous compilations. In collaboration with Commonwealth and State government agencies, we compiled and standardised thousands of boreholes, stratigraphic picks, 2D seismic and airborne electromagnetic data across the GAB. We undertook a detailed stratigraphic review on hundreds of key boreholes with geophysical logs to construct consistent regional transects across the GAB and LEB, using geological time constraints from hundreds of boreholes with existing and newly interpreted biostratigraphic data. We infilled the stratigraphic correlations along key transects across Queensland, New South Wales, South Australia and Northern Territory borders to refine nomenclature and stratigraphic relationships between the Surat, Eromanga and Carpentaria basins, improving chronostratigraphic understanding within the Jurassic to Cretaceous units. We extended the GAB geological framework to the overlying LEB to better resolve the Cenozoic stratigraphy and potential hydrogeological connectivity. New data and information fill gaps and refine the previous 3D hydrogeological model of the entire GAB and LEB. The new 3D geological and hydrostratigraphic model provides a framework to integrate additional hydrogeological and rock property data. It assists in refining hydraulic relationships between aquifers within the GAB and provides a basis for developing more detailed hydrogeological system conceptualisations. This is a step towards the future goal of quantifying hydraulic linkages with underlying basins, and overlying Cenozoic aquifers to underpin more robust understanding of the hydrogeological systems within the GAB. This approach can be extended to other regional hydrogeological systems. This Abstract was submitted/presented at the 2023 Australasian Exploration Geoscience Conference (AEGC) 13-18 March (https://2023.aegc.com.au/)

This web service provides access to geological, hydrogeological and hydrochemical digital datasets that have been published by Geoscience Australia for the Great Artesian Basin (GAB).

This web service provides access to geological, hydrogeological and hydrochemical digital datasets that have been published by Geoscience Australia for the Great Artesian Basin (GAB).

<div>This Geoscience Australia Record reports on Interferometric Synthetic Aperture Radar (InSAR) processing over the Great Artesian Basin (GAB) to support an improved understanding of the groundwater system and water balance across the region. InSAR is a geodetic technique that can identify ground surface movement from satellite data at a regional scale and is therefore a valuable and widely used technique for measuring patterns in surface movement over time; including the movement of fluids (i.e. water or gas) beneath the surface.</div><div><br></div><div>This Record is the one of two Geoscience Australia Records that describe ground surface movement monitoring Geoscience Australia have undertaken in the GAB in recent years. Namely;</div><div>1.&nbsp;&nbsp;&nbsp;&nbsp;Ground surface movement in the northern Surat Basin derived from campaign GPS measurements. (Garthwaite et al., 2022).</div><div>2.&nbsp;&nbsp;&nbsp;&nbsp;InSAR processing over the Great Artesian Basin and analysis over the western Eromanga Basin and northern Surat Basin (this Record).</div><div><br></div><div>We have produced ground surface motion data products, which cover about 90% of the GAB for the period of time between January 2016 and August 2020. The data products were created using Sentinel-1 Synthetic Aperture Radar (SAR) data and an InSAR processing workflow designed for large spatial scale processing. The large spatial scale InSAR processing workflow includes using GAMMA software to (i) pre-process SAR images to align the pixels, (ii) generate interferograms and short temporal baseline surface displacement maps and PyRate software to (iii) combine these outputs in an inversion to form pixel-wise time series ground surface displacement data and fit ground surface velocities to the displacement data. The raw SAR data and these subsequent data products of the workflow are partitioned into overlapping frames; the final stage of the large scale processing workflow is to combine the partitioned data into a single map using a mosaicking algorithm. The results of this processing chain demonstrate the feasibility of developing a regional scale ground surface movement reconnaissance tool (i.e. subsidence and uplift). </div><div><br></div><div>We provide a summary of the processing chain and data products and a focused assessment for two case study areas in the western Eromanga Basin (South Australia) and northern Surat Basin (Queensland). Over these case study areas we examine the relationship between the InSAR derived ground surface movement and available groundwater level data. We also assess how land use types may influence the InSAR derived ground surface motion data by comparing the InSAR data to the “land types” over the region which we classify using a machine learning algorithm with Sentinel-2 optical imagery data. </div><div><br></div><div>From our analysis we observe little ground surface motion over the western Eromanga Basin. The surface movement rate over the entire area is estimated to be mostly within ±10 mm/yr. Groundwater level time series data from well monitoring sites in the area did not appear to have any significant trends either. However, large and broad scale ground surface motion (both uplift and subsidence) was observed in the InSAR processing results over the northern Surat Basin. A 75 km x 150 km scale uplift signal, with rates of up to 20 mm/yr, was located over an area we classified as cultivated land, where InSAR signals are likely to be influenced by near-surface cultivation activities (such as irrigation) rather than subsurface groundwater level changes. Furthermore, two approximately 75km x 75 km areas were identified which had subsidence signals of up to -20 mm/yr. Over the same area, groundwater level time series data show long-term negative trends in the water head level. For a more direct comparison between the InSAR results and the well data, we fitted a first order poroelastic model to transform the InSAR derived ground surface motion rates into modelled pore-pressure decline/groundwater drawdown rates. We compared the model to the groundwater time series data in the Walloon Coal Measures, Surat Basin, and found good agreement, which indicates that the observed subsidence signals could be attributable to pore-pressure decline due to the falling water head level.</div><div><br></div><div>We finally provide some preliminary analysis comparing our InSAR results to the results from an Office of Groundwater Impact Assessment (OGIA) InSAR study and a Geoscience Australia GPS land movement study to assist in validating the Geoscience Australia InSAR results. Overall, the comparisons are encouraging, showing a high correlation against the OGIA InSAR results and GPS results. Further work, is required to further validate our results and reduce uncertainty in our analysis process.</div>

The document summarises new seismic interpretation metadata for two key horizons from Base Jurassic to mid-Cretaceous strata across the western and central Eromanga Basin, and the underlying Top pre-Permian unconformity. New seismic interpretations were completed during a collaborative study between the National Groundwater Systems (NGS) and Australian Future Energy Resources (AFER) projects. The NGS and AFER projects are part of Exploring for the Future (EFTF)—an eight year, $225 million Australian Government funded geoscience data and precompetitive information acquisition program 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 will help support a strong economy, resilient society and sustainable environment for the benefit of all Australians. The EFTF program is supporting Australia’s transition to a low emissions economy, industry and agriculture sectors, as well as economic opportunities and social benefits for Australia’s regional and remote communities. Further details are available at http://www.ga.gov.au/eftf. The seismic interpretations build on previous work undertaken as part of the ‘Assessing the Status of Groundwater in the Great Artesian Basin’ (GAB) Project, commissioned by the Australian Government through the National Water Infrastructure Fund – Expansion (Norton & Rollet, 2022; Vizy & Rollet, 2022; Rollet et al., 2022; Rollet et al., in press.), the NGS Project (Norton & Rollet, 2023; Rollet et al., 2023; Vizy & Rollet, 2023) and the AFER Project (Bradshaw et al., 2022 and in press, Bernecker et al., 2022, Iwanec et al., 2023; Iwanec et al., in press). The recent iteration of revisions to the GAB geological and hydrogeological surfaces (Vizy & Rollet, 2022) provides a framework to interpret various data sets consistently (e.g., boreholes, airborne electromagnetic, seismic data) and in a 3D domain, to improve our understanding of the aquifer geometry, and the lateral variation and connectivity in hydrostratigraphic units across the GAB (Rollet et al., 2022). Vizy and Rollet (2022) highlighted some areas with low confidence in the interpretation of the GAB where further data acquisition or interpretation may reduce uncertainty in the mapping. One of these areas was in the western and central Eromanga Basin. New seismic interpretations are being used in the western Eromanga, Pedirka and Simpson basins to produce time structure and isochore maps in support of play-based energy resource assessment under the AFER Project, as well as to update the geometry of key aquifers and aquitards and the GAB 3D model for future groundwater management under the NGS Project. These new seismic interpretations fill in some data and knowledge gaps necessary to update the geometry and depth of key geological and hydrogeological surfaces defined in a chronostratigraphic framework (Hannaford et al., 2022; Bradshaw et al., 2022 and in press; Hannaford & Rollet, 2023). The seismic interpretations are based on a compilation of newly reprocessed seismic data (Geoscience Australia, 2022), as part of the EFTF program, and legacy seismic surveys from various vintages brought together in a common project with matching parameters (tying, balancing, datum correcting, etc.). This dataset has contributed to a consolidated national data coverage to further delineate groundwater and energy systems, in common data standards and to be used further in integrated workflows of mineral, energy and groundwater assessment. The datasets associated with the product provides value added seismic interpretation in the form of seismic horizon point data for two horizons that will be used to improve correlation to existing studies in the region. The product also provides users with an efficient means to rapidly access a list of core data used from numerous sources in a consistent and cleaned format, all in a single package. The following datasets are provided with this product: 1) Seismic interpretation in a digital format (Appendix A), in two-way-time, on key horizons with publically accessible information, including seismic interpretation on newly reprocessed data: Top Cadna-owie; Base Jurassic; Top pre-Permian; 2) List of surveys compiled and standardised for a consistent interpretation across the study area (Appendix B). 3) Isochore points between Top Cadna-owie and Base Jurassic (CC10-LU00) surfaces (Appendix C). 4) Geographical layer for the seismic lines compiled across Queensland, South Australia and the Northern Territory (Appendix D). These new interpretations will be used to refine the GAB geological and hydrogeological surfaces in this region and to support play-based energy resource assessments in the western Eromanga, Pedirka and Simpson basins.

This report presents a stratigraphic review of some key boreholes across the Jurassic-Cretaceous Eromanga, Surat and Carpentaria basins that form the groundwater Great Artesian Basin (GAB), as well as across the overlying Cenozoic Lake Eyre Basin (LEB), completed during the National Groundwater Systems (NGS) Project. The NGS Project is part of Exploring for the Future (EFTF)—an eight year, $225 million Australian Government funded geoscience data and information acquisition program focused on better understanding the potential mineral, energy and groundwater resources across Australia. The study presented here builds on previous work (Norton & Rollet, 2022a) undertaken as part of the ‘Assessing the Status of Groundwater in the Great Artesian Basin’ Project, commissioned by the Australian Government through the National Water Infrastructure Fund – Expansion. Although not intended to be a major re-interpretation of existing data, this stratigraphy review updates stratigraphic picks where necessary to obtain a consistent interpretation across the study area, based on the refined geological and hydrostratigraphical framework developed through this project. Problems and inconsistencies in the input data or current interpretations have been highlighted to suggest where further studies or investigations may be useful. This study includes Phase 2 of the National Groundwater Systems Project, which was undertaken by Catherine Jane Norton in collaboration with Geoscience Australia; and compiled, processed and correlated a variety of borehole log data to review the stratigraphy and improve the understanding of distribution and characteristics of Jurassic and Cretaceous sediments across the Eromanga and Surat basins and overlying LEB. To complement the previous 322 key boreholes compiled in Phase 1 (Norton & Rollet, 2022) additional stratigraphic correlations have been made between geological units of similar age (constrained using palynological data) from 706 key boreholes along 35 regional transects across the GAB and from 406 key boreholes along 20 regional transects across the central LEB. Also included in this study is Phase 3 in-fill work of four additional transects, extending the study further south in New South Wales, to tie in to the Cenozoic of the Murray Basin. This later phase 3 of the project also included a review and quality control of approximately 2,572 central LEB boreholes, and the addition of 278 boreholes in the GAB in southern Queensland and New South Wales. Phase 3 also expanded on the results used for mapping regional sand/shale ratios that began in the previous phase (Evans et al., 2020; Norton & Rollet, 2022a). Normalised Gamma Ray (GR) calculations have now been made for 1,778 LEB boreholes and 676 GAB boreholes spanning the entire sequence from the surface, through the Cenozoic and down to the base Jurassic unconformity. The previous phase, mentioned above, concentrated on either just the LEB or the GAB intervals from Cadna-owie Formation to base Jurassic. An additional 17 transects in the LEB and 27 transects in the GAB were created to visualise the lithological variation. The distribution of generalised sand/shale ratios are used to estimate the thickness of sand and shale in different formations, with implications for formation porosity and the hydraulic properties of aquifers and aquitards. This study fills data gaps identified in the previous study (Norton & Rollet, 2022) and refines the regional distribution of lithological heterogeneity in each hydrogeological unit, contributing to an improved understanding of connectivity within and between aquifers. The datasets compiled and examined in this study are in Appendix A. Attempts were made to standardise lithostratigraphic units, which are currently described using varying nomenclature, to produce a single chronostratigraphic chart across the entirety of the GAB and LEB basins. The main stratigraphic correlation infill in the GAB and LEB regions focused on: • The transition between the Eromanga and Surat basins in New South Wales and the tie-in to existing transects in Queensland and South Australia, • The Eromanga Basin in South Australia and Queensland and the tie-in to Phase 1 transects, • The central Eromanga Basin and Frome Embayment areas, extending the GAB units to the overlying Lake Eyre Basin stratigraphy to better assess potential connectivity between these basins, • The transition between the Lake Eyre and Murray Basins in the Upper Darling Floodplain (UDF) area in New South Wales and the tie-in to Phase 1 transects in New South Wales. This report and associated data package provide a data compilation on 706 and 278 key boreholes in the Surat and Eromanga basins respectively, to assist in updating the geological framework for the GAB and LEB. Recommendations are provided for further studies to continue refining the understanding of the stratigraphy in the Great Artesian and Lake Eyre basins.

The National Groundwater Systems (NGS) project, is part of the Australian Government’s Exploring for the Future (EFTF) program, led by Geoscience Australia (https://www.eftf.ga.gov.au/national-groundwater-systems), to improve understanding of Australia’s groundwater resources to better support responsible groundwater management and secure groundwater resources into the future. The project is developing new national data coverages .to further delineate groundwater systems and improve data standards and workflows of groundwater assessment. While our conceptual understanding of the hydrogeology of the Great Artesian Basin (GAB, Figure 1) continues to grow, in many parts of the Eromanga, Surat and Carpentaria basins that form the GAB we are still reliant on legacy data and knowledge from the 1970s of variable quality. Additional information provided by recent studies in various parts of the GAB highlights the level of architectural complexity and spatial variability in stratigraphic and hydrostratigraphic units across the basin. We now recognise the need to standardise these regional studies to map such geological complexity in a consistent, basin-wide hydrostratigraphic framework that can support effective long-term management of GAB water resources. The recent iteration of revision of GAB geological and hydrogeological surfaces (Vizy & Rollet, 2022) provides a framework to interpret various data sets consistently (e.g., boreholes, airborne electromagnetic, seismic data) and in a 3D domain, to improve the aquifer geometry, and the lateral variation and connectivity in hydrostratigraphic units across the GAB (Rollet et al., 2022). Vizy and Rollet (2022) highlighted some areas with low confidence in the interpretation of the GAB where further data acquisition or interpretation may reduce uncertainty in the mapping. One of these areas was in the Carpentaria Basin, particularly the transition from the offshore to onshore across the Gulf of Carpentaria. This data compilation provides open file SEGY, cultural data and value added seismic interpretation in the form of seismic horizons and grids for two key surfaces, these enable improved correlation to existing studies. This data also aim to provide users an efficient mean to rapidly access core data from numerous sources in a consistent and cleaned format, all in a single package. This dataset provides: 1) Seismic data compilation in a digital format with publically accessible information, including scanned seismic sections converted to SEGY format where digital data was not available; 2) Base Mesozoic and Near Base Cenozoic seismic interpretation in two-way-time; 3) Depth converted regional surfaces for the Base Mesozoic and Near Base Cenozoic unconformities generated using additional constraints such as AEM interpretation and borehole constraints previously compiled in Vizy & Rollet (2022). This new interpretation will be used to refine the GAB geological and hydrogeological surfaces in this region.

This data package provides seismic interpretations that have been generated in support of the energy resource assessments under the Australia’s Future Energy Resources (AFER) project. Explanatory notes are also included. The AFER project is part of Geoscience Australia’s Exploring for the Future (EFTF) Program—an eight year, $225 million Australian Government funded geoscience data and precompetitive information acquisition program 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, Geoscience Australia is building a national picture of Australia’s geology and resource potential. This will help support a strong economy, resilient society and sustainable environment for the benefit of all Australians. The EFTF program is supporting Australia’s transition to a low emissions economy, industry and agriculture sectors, as well as economic opportunities and social benefits for Australia’s regional and remote communities. Further details are available at http://www.ga.gov.au/eftf. The seismic interpretations build on the recently published interpretations by Szczepaniak et al. (2023) by providing updated interpretations in the AFER Project area for the Top Cadna-owie (CC10) and Top Pre-Permian (ZU) horizons, as well as interpretations for 13 other horizons that define the tops of play intervals being assessed for their energy resource potential (Figure 1). Seismic interpretations for the AFER Project are constrained by play interval tops picked on well logs that have been tied to the seismic profiles using time-depth data from well completion reports. The Pedirka and Western Eromanga basins are underexplored and contain relatively sparse seismic and petroleum well data. The AFER Project has interpreted play interval tops in 41 wells, 12 seismic horizons (Top Cadna-owie and underlying horizons) on 238 seismic lines (9,340 line kilometres), and all 15 horizons on 77 recently reprocessed seismic lines (3,370 line kilometres; Figure 2). Note that it has only been possible to interpret the Top Mackunda-Winton, Top Toolebuc-Allaru and Top Wallumbilla horizons on the reprocessed seismic lines as these are the only data that provide sufficient resolution in the shallow stratigraphic section to confidently interpret seismic horizons above the Top Cadna-owie seismic marker. The seismic interpretations are provided as point data files for 15 horizons, and have been used to constrain the zero edges for gross-depositional environment maps in Bradshaw et al. (2023) and to produce depth-structure and isochore maps for each of the 14 play intervals in Iwanec et al. (2023). The data package includes the following datasets: 1) Seismic interpretation point file data in two-way-time for up to 15 horizons using newly reprocessed seismic data and a selection of publicly available seismic lines (Appendix A). 2) Geographical layers for the seismic lines used to interpret the top Cadna-owie and underlying horizons (Cadnaowie_to_TopPrePermian_Interpretation.shp), and the set of reprocessed lines used to interpret all 15 seismic horizons (All_Horizons_Interpretation.shp; Appendix B). These seismic interpretations are being used to support the AFER Project’s play-based energy resource assessments in the Pedirka and Western Eromanga basins.

<b>This data package is superseded by a second iteration presenting updates on 3D geological and hydrogeological surfaces across eastern Australia that can be accessed through </b><a href="https://dx.doi.org/10.26186/148552">https://dx.doi.org/10.26186/148552</a> The Australian Government, through the National Water Infrastructure Fund – Expansion, commissioned Geoscience Australia to undertake the project ‘Assessing the Status of Groundwater in the Great Artesian Basin’ (GAB). The project commenced in July 2019 and will finish in June 2022, with an aim to develop and evaluate new tools and techniques to assess the status of GAB groundwater systems in support of responsible management of basin water resources. While our hydrogeological conceptual understanding of the GAB continues to grow, in many places we are still reliant on legacy data and knowledge from the 1970s. Additional information provided by recent studies in various parts of the GAB highlights the level of complexity and spatial variability in hydrostratigraphic units across the basin. We now recognise the need to link these regional studies to map such geological complexity in a consistent, basin-wide hydrostratigraphic framework that can support effective long-term management of GAB water resources. Geological unit markers have been compiled and geological surfaces associated with lithostratigraphic units have been correlated across the GAB to update and refine the associated hydrogeological surfaces. Recent studies in the Surat Basin in Queensland and the Eromanga Basin in South Australia are integrated with investigations from other regions within the GAB. These bodies of work present an opportunity to link regional studies and develop a revised, internally consistent geological framework to map geological complexity across the GAB. Legacy borehole data from various sources, seismic and airborne electromagnetic (AEM) data were compiled, then combined and analysed in a common 3D domain. Correlation of interpreted geological units and stratigraphic markers from these various data sets are classified using a consistent nomenclature. This nomenclature uses geological unit subdivisions applied in the Surat Cumulative Management Area (OGIA (Office of Groundwater Impact Assessment), 2019) to correlate time equivalent regional hydrogeological units. Herein we provide an update of the surface extents and thicknesses for key hydrogeological units, reconciling geology across borders and providing the basis for a consistent hydrogeological framework at a basin-wide scale. The new surfaces can be used for facilitating an integrated basin systems assessment to improve our understanding of potential impacts from exploitation of sub-surface resources (e.g., extractive industries, agriculture and injection of large volumes of CO2 into the sub-surface) in the GAB and providing a basis for more robust water balance estimates. This report is associated with a data package including (Appendix A – Supplementary material): • Nineteen geological and hydrogeological surfaces from the Base Permo-Carboniferous, Top Permian, Base Jurassic, Base Cenozoic to the surface (Table 2.1), • Twenty-one geological and hydrogeological unit thickness maps from the top crystalline basement to the surface (Figure 3.7 to Figure 3.27), • The formation picks and constraining data points (i.e., from boreholes, seismic, AEM and outcrops) compiled and used for gridding each surface (Table 3.8).

This report presents the results of an assessment of geoscience data and tools applied in the eastern Eromanga Basin to improve the hydrogeological conceptualisations. The assessment is one component of the Australian Government funded project ‘Assessing the Status of Groundwater in the Great Artesian Basin’. The results demonstrate that the application of existing and new geoscientific data and technologies has the potential to further improve our understanding of the Great Artesian Basin (GAB) hydrogeological system thus supporting the responsible management of basin water resources. Hydrogeological synthesis using airborne electromagnetic data, in conjunction with hydro- and chrono-stratigraphic data and well geological information, are effective at mapping the three dimensional distribution of the aquifers and aquitards. The results lead to an improved understanding of groundwater intake bed geometry, potential connectivity between aquifers, possible structural controls on groundwater flow paths, and plausible source of groundwater discharging as springs. In the southern part of the study area, the dominantly shale-rich Evergreen Formation is electrically conductive, but is locally resistive in places due to sand-rich facies. These areas allow hydraulic connectivity between the overlying and underlying Hutton and Precipice sandstone aquifers. Anticlinal folds and juxtaposed strata are observed on AEM traverses along the strike of the aquifer units, and includes the Hutton, Adori and Cadna-owie – Hooray sandstones. Abrupt folding and juxtaposed strata were interpreted as fault zones. Both structural features have the potential of controlling groundwater flow directions or groundwater storage compartmentalisation. The northern limits of Precipice Sandstone and Evergreen Formation are at Blackall and south of Barcaldine towns respectively. This zone also coincides with the southern edge of the east-west trending sub-surface Barcaldine Ridge where the basal Jurassic sequence abut against. On and north of the Barcaldine Ridge, the Cadna-owie – Hooray, Adori and Hutton sandstones are present. Mapping using AEM conductivity sections affirm that the Hutton Sandstone is the major aquifer in the northern part of the study area. The Poolowanna Formation, an age equivalent to the Evergreen Formation and Precipice Sandstone, is laterally extensive towards the northern part of the study area. This formation crops-out west of Lake Buchanan in the Great Dividing Range, but forms sub-crops elsewhere along the groundwater recharge areas. Numerous groundwater springs and spring clusters are present along the east and west of the outcropping sandstone hills in the Great Dividing Range. In the northern parts of the study area, source of groundwater for the springs are mainly derived from the Hutton Sandstone aquifers through either gravity-feed or lateral groundwater flow process. Polygonal faults mainly occur on conductive and fined-grained sedimentary units of the Rolling Downs Group. There is lack of observable evidence from AEM conductivity sections on the presence of polygonal faults to suggest preferential groundwater flows along these potential hydraulic conduits. Further investigation using ground based methods are needed to establish the presence of the faults and their hydraulic properties.