<div>This was the last of five presentations held on 31 July 2023 as part of the National Groundwater Systems Workshop. Towards developing a 3D hydrogeological framework for Australia: A common chronostratigraphic framework for aquifers&nbsp;</div><div><br></div>

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/)

<div>As part of the Exploring for the Future (EFTF) programme, the groundwater team undertook an in-depth investigation into characterising surface water -- groundwater interaction in the Cooper Creek floodplain using airborne electromagnetics (AEM). This work is to be released as part of the Lake Eyre Basin detailed inventory and as an EFTF extended abstract. As part of Geoscience Australia's commitment to transparent science, the scientific workflows that underpinned a large component of this investigation are to be released as a jupyter notebook. This notebook contains python code, figures and explanatory text that the reader can use to understand how the AEM data were processed, visualised, integrated with other data and interpreted.</div>

This was the third of five presentations held on 31 July 2023 as part of the National Groundwater Systems Workshop - WaMSTeC: Water Monitoring and Standardisation Technical Committee National Industry Guidelines for hydrometric monitoring WaMSTeC GUIDELINE REVISIONS UPDATE FOR GROUNDWATER COMPONENTS: GROUNDWATER SUBCOMMITTEE

This was the first of five presentations held on 31 July 2023 as part of the National Groundwater Systems Workshop - A clear and consistent inventory of knowledge about Australia’s major hydrogeological provinces.

The Exploring for the Future program Showcase 2023 was held on 15-17 August 2023. Day 1 - 15th August talks included: Resourcing net zero – Dr Andrew Heap Our Geoscience Journey – Dr Karol Czarnota You can access the recording of the talks from YouTube here: <a href="https://youtu.be/uWMZBg4IK3g">2023 Showcase Day 1</a>

<div>This dataset presents results of a first iteration of a 3D geological model across the Georgina Basin, Beetaloo Sub-basin of the greater McArthur Basin and South Nicholson Basin (Figure 1), completed as part of Geoscience Australia’s Exploring for the Future Program National Groundwater Systems (NGS) Project. These basins are located in a poorly exposed area between the prospective Mt Isa Province in western Queensland, the Warramunga Province in the Northern Territory, and the southern McArthur Basin to the north. These surrounding regions host major base metal or gold deposits, contain units prospective for energy resources, and hold significant groundwater resources. The Georgina Basin has the greatest potential for groundwater.</div><div>&nbsp;</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. More information is available at http://www.ga.gov.au/eftf and https://www.eftf.ga.gov.au/national-groundwater-systems.</div><div>&nbsp;</div><div>This model builds on the work undertaken in regional projects across energy, minerals and groundwater aspects in a collection of data and interpretation completed from the first and second phases of the EFTF program. The geological and geophysical knowledge gathered for energy and minerals projects is used to refine understanding of groundwater systems in the region.</div><div>&nbsp;</div><div>In this study, we integrated interpretation of a subset of new regional-scale data, which include ~1,900 km of deep seismic reflection data and 60,000 line kilometres of AusAEM1 airborne electromagnetic survey, supplemented with stratigraphic interpretation from new drill holes undertaken as part of the National Drilling Initiative and review of legacy borehole information (Figure 2). A consistent chronostratigraphic framework (Figure 3) is used to collate the information in a 3D model allowing visualisation of stacked Cenozoic Karumba Basin, Mesozoic Carpentaria Basin, Neoproterozoic to Paleozoic Georgina Basin, Mesoproterozoic Roper Superbasin (including South Nicholson Basin and Beetaloo Sub-basin of the southern McArthur Basin), Paleoproterozoic Isa, Calvert and Leichhardt superbasins (including the pre-Mesoproterozoic stratigraphy of the southern McArthur Basin) and their potential connectivity. The 3D geological model (Figure 4) is used to inform the basin architecture that underpins groundwater conceptual models in the region, constrain aquifer attribution and groundwater flow divides. This interpretation refines a semi-continental geological framework, as input to national coverage databases and informs decision-making for exploration, groundwater resource management and resource impact assessments.</div><div><br></div><div>This metadata document is associated with a data package including:</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Nine surfaces (Table 1): 1-Digital elevation Model (Whiteway, 2009), 2-Base Cenozoic, 3-Base Mesozoic, 4-Base Neoproterozoic, 5-Base Roper Superbasin, 6-Base Isa Superbasin, 7-Base Calvert Superbasin, 8-Base Leichhardt Superbasin and 9-Basement.</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Eight isochores (Table 4): 1-Cenozoic sediments (Karumba Basin), 2-Mesozoic sediments (Carpentaria and Eromanga basins), 3-Paleozoic and Neoproterozoic sediments (Georgina Basin), 4-Mesoproterozoic sediments (Roper Superbasin including South Nicholson Basin and Beetaloo Sub-basin), 5-Paleoproterozoic Isa Superbasin, 6-Paleoproterozoic Calvert Superbasin, 7-Paleoproterozoic Leichhardt Superbasin and 8-Undifferentiated Paleoproterozoic above basement.</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Five confidence maps (Table 5) on the following stratigraphic surfaces: 1-Base Cenozoic sediments, 2-Base Mesozoic, 3-Base Neoproterozoic, 4-Base Roper Superbasin and 5-Combination of Base Isa Superbasin/Base Calvert Superbasin/Base Leichhardt Superbasin/Basement.</div><div>·&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Three section examples (Figure 4) with associated locations.</div><div>Two videos showing section profiles through the model in E-W and N-S orientation.</div>

<div> Airborne electromagnetic (AEM) data has been acquired at 20km line spacing across much of the Australian continent and conductivity models generated by inverting these data are freely available. Despite the wide line spacing these data are suitable for imaging the near surface and better understanding groundwater systems. Twenty-kilometre spaced AEM data acquired over the Cooper Creek floodplain using a fixed-wing towed system were inverted using deterministic and probabilistic methods. The Cooper Creek is an anabranching ephemeral river system in arid eastern central Australia. We integrated conductivity data with a range of surface and subsurface data to characterise the hydrogeology of the region and infer groundwater salinity from the shallow alluvial aquifer across a more than 14,000 km2 Cooper Creek floodplain. The conductivity data also revealed several examples of focused recharge through a river channel forming a freshwater lens within the more regional shallow saline groundwater system.</div><div>&nbsp;</div><div>This work demonstrates that regional AEM conductivity data can be a valuable tool for understanding groundwater processes at various scales with implications for how to responsibly manage water resources. This work is especially important in the Australian context where high quality borehole data is typically sparse, but high-quality geophysical and satellite data are often accessible.</div><div> </div> This presentation was given to the 8th International Airborne Electromagnetics Workshop (AEM2023) (https://www.aseg.org.au/news/aem-2023)

<div>The Lake Eyre surface water catchment covers around 1,200,000 km2 of central Australia, about one-sixth of the entire continent. It is one of the largest endorheic river basins in the world and contains iconic arid streams such as the Diamantina, Finke and Georgina rivers, and Cooper Creek. The Lake Eyre region supports diverse native fauna and flora, including nationally significant groundwater-dependent ecosystems such as springs and wetlands which are important cultural sites for Aboriginal Australians.</div><div><br></div><div>Much of the Lake Eyre catchment is underlain by the geological Lake Eyre Basin (LEB). The LEB includes major sedimentary depocentres such as the Tirari and Callabonna sub-basins which have been active sites of deposition throughout the Cenozoic. The stratigraphy of the LEB is dominated by the Eyre, Namba and Etadunna formations, as well as overlying Pliocene to Quaternary sediments.</div><div><br></div><div>The National Groundwater Systems Project, part of Geoscience Australia's Exploring for the Future Program (https://www.eftf.ga.gov.au/), is transforming our understanding of the nation's major aquifer systems. With an initial focus on the Lake Eyre Basin, we have applied an integrated geoscience systems approach to model the basin's regional stratigraphy and geological architecture. This analysis has significantly improved understanding of the extent and thickness of the main stratigraphic units, leading to new insights into the conceptualisation of aquifer systems in the LEB.</div><div><br></div><div>Developing the new understanding of the LEB involved compilation and standardisation of data acquired from thousands of petroleum, minerals and groundwater bores. This enabled consistent stratigraphic analysis of the major geological surfaces across all state and territory boundaries. In places, the new borehole dataset was integrated with biostratigraphic and petrophysical data, as well as airborne electromagnetic (AEM) data acquired through AusAEM (https://www.eftf.ga.gov.au/ausaem). The analysis and integration of diverse geoscience datasets helped to better constrain the key stratigraphic horizons and improved our overall confidence in the geological interpretations.</div><div><br></div><div>The new geological modelling of the LEB has highlighted the diverse sedimentary history of the basin and provided insights into the influence of geological structures on modern groundwater flow systems. Our work has refined the margins of the key depocentres of the Callabonna and Tirari sub-basins, and shown that their sediment sequences are up to 400 m thick. We have also revised maximum thickness estimates for the main units of the Eyre Formation (185 m), Namba Formation (265 m) and Etadunna Formation (180 m).</div><div><br></div><div>The geometry, distribution and thickness of sediments in the LEB is influenced by geological structures. Many structural features at or near surface are related to deeper structures that can be traced into the underlying Eromanga and Cooper basins. The occurrence of neotectonic features, coupled with insights from geomorphological studies, implies that structural deformation continues to influence the evolution of the basin. Structures also affect the hydrogeology of the LEB, particularly by compartmentalising groundwater flow systems in some areas. For example, the shallow groundwater system of the Cooper Creek floodplain is likely segregated from groundwater in the nearby Callabonna Sub-basin due to structural highs in the underlying Eromanga Basin.</div><div> Abstract submitted and presented at the 2023 Australian Earth Science Convention (AESC), Perth WA (https://2023.aegc.com.au/)

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.