Authors / CoAuthors
Evans, T. | Lewis, S. | Symington, N. | Hansen, J. | Norton, C.J. | Hannaford, C. | Halas, L.
Abstract
<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/)
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document
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147778
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Keywords
- ( Project )
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- National Groundwater Systems
- ( Project )
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- EFTF – Exploring for the Future
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- Lake Eyre Basin
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- Cenozoic
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- groundwater connectivity
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- Namba Formation
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- Eyre Formation
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- Etadunna Formation
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- Callabonna Sub-basin
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- Cooper Creek
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- hydrogeology
- theme.ANZRC Fields of Research.rdf
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- Groundwater hydrologyStratigraphy (incl. biostratigraphysequence stratigraphy and basin analysis)Structural geology and tectonics
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- Published_External
Publication Date
2023-09-19T22:51:22
Creation Date
2023-03-11T07:00:00
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Purpose
This is a short abstract written for submission to the Australian Earth Sciences Convention (AESC) 2023. This conference will be held in Perth, 27 to 30 June 2023. The abstract is being submitted to be considered for an oral presentation as part of the conference technical program. The abstract discusses work undertaken on the hydrogeology and groundwater systems of the Lake Eyre Basin as part of the National Groundwater Systems Project under the Exploring for the Future (EFTF) Program.
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Australian Earth Science Convention (AESC) 27-30 July 2023 Perth WA
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<div>This short conference abstract has been written based on the broader body of analytical and interpretive work undertaken for the Lake Eyre Basin detailed groundwater inventory under the National Groundwater Systems (NGS) Project, Exploring for the Future (EFTF) Program. The main findings of this inventory will be published as a future GA Record, expected around mid-2023. The purpose of the abstract is to obtain an oral presentation as part of the AESC 2023 program in order to promote broader knowledge and understanding of the outputs from the Lake Eyre Basin study. </div>
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