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  • The Great Artesian Basin (GAB) covers one fifth of Australia and is the largest groundwater ‘basin’ on the continent. Groundwater from the GAB is a vital resource for pastoral, agricultural and extractive industries, underpinning at least $12.8 billion in economic activity annually, as well as providing town water supplies and supporting environmental and cultural values. The Australian Government, through the National Water Infrastructure Development Fund – Expansion, commissioned Geoscience Australia to undertake the project ‘Assessing the Status of Groundwater in the Great Artesian Basin’. A key deliverable of this project is a water balance (for 2019) encompassing the main aquifers of the GAB. To facilitate this outcome, a range of tools and techniques to assist in the development of improved hydrogeological conceptualisations of the GAB have been developed and assessed. This report presents the results of investigations from a pilot study area in the northern Surat Basin, Queensland, with components of the work extending into the wider GAB. The results demonstrate that the application of existing and new geoscientific data and technologies has the potential to further improve our understanding of the GAB hydrogeological system thus supporting the responsible management of basin water resources. Groundwater recharge potential within the GAB intake beds has been investigated using techniques that consider variations in physical and environmental characteristics. Empirical modelling assessing deep drainage as a recharge proxy suggests that, with isolated exceptions, diffuse recharge potential is generally low across most of the study area. The spatial variability in recharge potential can assist in the interpretation and/or interpolation of estimates derived from other techniques, such as chloride mass balance. The results of machine learning modelling suggest that further work is needed to better constrain uncertainty in input and training datasets, and in the development of robust translations of outputs to hydrogeologically meaningful products. The chloride mass balance (CMB) method remains the most appropriate tool for estimating long-term mean gross recharge to GAB aquifers in the northern Surat Basin. New upscaling methods provide significant improvements for mapping regional scale groundwater recharge rates and quantifying uncertainties associated with these estimates. Application of multiple techniques to the assessment of groundwater flow and recharge processes is necessary to complement CMB recharge estimates, and reduce associated uncertainty. Analysis of groundwater environmental tracers are recommended for constraining CMB recharge rates. Integrated geological assessments using airborne electromagnetic data in conjunction with other geophysical and geological data (e.g., reflection seismic, wells) are effective at characterising aquifer architecture to better understand geometry, flow pathways and structural controls relevant to recharge and connectivity at local to regional scales. Significant effort has gone into updating the regional geological framework at the whole-of-GAB scale, combining legacy and new data with recent knowledge to revise the hydrogeological conceptualisation of the GAB. This assists in constraining interpretations of regional depositional architecture and lithological heterogeneity within hydrogeological units, particularly those properties that influence groundwater storage and flux. Assessment of lateral and vertical heterogeneity of hydraulic properties within and between aquifers and aquitards in the northern Surat Basin has refined our understanding of potential groundwater connectivity and compartmentalisation. This study provides an improved hydrogeological framework to support revised water balance estimates for the GAB, and insights into potential recharge variability that may impact those input components. Targeted examples from the northern Surat Basin demonstrate the application of the techniques and tools employed, including methods to reduce uncertainty. The outcomes of this work underpin a revised hydrogeological conceptualisation for the GAB, a standardised basis for establishing future investigations, and a framework for more informed water management decision-making.

  • The Australian Capital Territory Geochemical Urban Mapping (ACTGUM) project, a collaboration between the National Centre for Forensic Studies at the University of Canberra, Geoscience Australia (GA) and the Australian Federal Police, aims to enable high-quality research investigating the provenancing of topsoil in a law enforcement/intelligence context. Although many geochemical soil surveys already exist, these are typically developed primarily for exploration and related earth sciences, limiting their use for forensic applications that have specific, and often differing requirements (e.g. sampling density, sampling medium and depth, and data treatment). An important part of the project is the development of a high quality, internally consistent, geochemical dataset of topsoil, covering a model area of interest at a relatively high sampling density. Initiated in 2017, a soil geochemical survey has been completed, covering the urban and surrounding suburban areas of Canberra, Australian Capital Territory (ACT), in inland southeastern Australia. At present, a total of 823 topsoil samples (including field replicate samples at 65 sites) have been collected from 686 sites, including 6 resampled sites, which together cover over 650 km2 at the average sample density of 1 site per 1 km2. Samples were collected from urban and suburban public parks, nature reserves, roadside verges, nature strips, and private agricultural land. Obvious areas of anthropogenically introduced, modified or contaminated soils were avoided. At each site, a 1 – 2 kg composite of five subsamples taken from the corners and centre of a 1m x 1m area at a depth interval of 0 – 5 cm was collected, after removal of surface vegetation. All composite samples were subsequently air dried, homogenised and split into two halves. One half was set aside for archiving. The remainder was dry sieved to <75 μm, consistent with existing geochemical surveys in Australia, including the GA National Geochemical Survey of Australia and GA Northern Australian Geochemical Survey. Any excess sample/fraction was kept for potential future use. All subsequent analytical protocols were applied to the <75 μm fraction, and those performed at the GA inorganic laboratory include: (1) X-ray fluorescence (XRF) analysis of fused beads and loss on ignition (LOI) (total geochemistry); and (2) Inductively coupled plasma – mass spectrometry (ICP-MS) analysis of total digestions of fused bead fragments (total geochemistry). Additional and complimentary measurements have been completed elsewhere, including magnetic susceptibility, ICP-MS analysis of aqua regia digests, Munsell soil colour, and X-ray diffraction (XRD) analysis. These measurements have been discussed elsewhere and/or will be published separately. In the present project manual, we describe the: (1) The synopsis underpinning the broader project and determination of sampling sites; and (2) Detailed protocols for sample collection, preparation and analysis of total element content. Release and interpretation of the project dataset, quality assessments and geochemical maps will be published separately.

  • This South Australian Gulf and Yorke Cenozoic Basins dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The South Australian Gulf and Yorke Cenozoic basins consist of eleven separate basins with similar sediments. These relatively small to moderate-sized basins overlies older rocks from the Permian, Cambrian, or Precambrian periods and are often bounded by north-trending faults or basement highs. The largest basins, Torrens, Pirie, and Saint Vincent, share boundaries. The Torrens and Pirie basins are fault-bounded structural depressions linked to the Torrens Hinge Zone, while the Saint Vincent basin is a fault-bounded intra-cratonic graben. Smaller isolated basins include Carribie and Para Wurlie near the Yorke Peninsula, and Willochra and Walloway in the southern Flinders Ranges. The Barossa Basin, Hindmarsh Tiers, Myponga, and Meadows basins are in the Adelaide region. These basins resulted from tectonic movements during the Eocene Australian-Antarctic separation, with many forming in the late Oligocene. Sediment deposition occurred during the Oligocene to Holocene, with various environments influenced by marine transgressions and regressions. The well-studied Saint Vincent Basin contains diverse sediments deposited in fluvial, alluvial, deltaic, swamp, marine, littoral, beach, and colluvial settings, with over 30 major shoreline migrations. Eocene deposition formed fluvio-deltaic lignite and sand deposits, before transitioning to deeper marine settings. The Oligocene and Miocene saw limestone, calcarenite, and clay deposition, overlain by Pliocene marine sands and limestones. The uppermost sequences include interbedded Pliocene to Pleistocene limestone, sand, gravel, and clay, as well as Pleistocene clay with minor sand lenses, and Holocene to modern coastal deposits. The sediment thickness varies from less than 50 m to approximately 600 m, with the Saint Vincent Basin having the most substantial infill. Some basins were previously connected to the Saint Vincent Basin's marine depositional systems but later separated due to tectonic movements.

  • This Central Australian Cenozoic Basins dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. Cenozoic basins are an important source of readily accessible groundwater within the arid deserts of central Australia. This province represents a collection of six notable Cenozoic basins within the region, including the Ti Tree, Waite, Hale, Mount Wedge, Lake Lewis and Alice Farm basins. Many local communities in this region (such as Papunya, Ti Tree and Ali Curung) rely upon groundwater stored within Cenozoic basin aquifers for their water security. The basins typically contain up to several hundred metres of saturated sediments that can include relatively thick intervals of hydraulically conductive sands, silts and minor gravels. It is noted that the potential groundwater storage volumes in the Cenozoic basins are much greater than the annual amount of runoff and recharge that occurs in central Australia, making them prospective targets for groundwater development. Groundwater quality and yields are variable, although relatively good quality groundwater can be obtained at suitable yields in many areas for community water supplies, stock and domestic use and irrigated horticulture operations, for example, in the Ti Tree Basin. However, not all of the Cenozoic basins have the potential to supply good quality groundwater resources for community and horticultural supplies. With the exception of several small sub-regions, most of the Waite Basin has very little potential to supply good quality groundwater for agricultural use. This is mainly due to limited aquifer development, low yielding bores and elevated groundwater salinity (commonly >2000 mg/L Total Dissolved Solids). However, bores have been successfully installed for smaller-scale pastoral stock and domestic supplies and small communities or outstations in the Waite Basin.

  • This Western Australian Fractured Rock Province dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The geological evolution of Australia can be summarised as a west-to-east growth pattern, resulting from the assembly and disintegration of several supercontinents since the Archean era. The oldest rocks are found in Western Australia, specifically within the Western Australia fractured rock province, which consists of two crustal elements: the West Australian Element and the Pinjarra Element. The Yilgarn and Pilbara cratons in the West Australian Element host the oldest rocks in continental Australia, featuring high-grade gneiss belts, granite-greenstone belts, and significant gold and iron ore deposits. The Yilgarn Craton is older in the west and can be divided into several terranes, with the eastern regions hosting world-class gold deposits. The Pilbara Craton, on the other hand, consists of granitoid-greenstone terrain and is rich in banded iron formations, leading to the world's richest iron ore deposits in the Hamersley Basin. The Gascoyne Province forms the medium- to high-grade metamorphic core of the orogeny in the West Australian Element. The Albany-Fraser Orogen and Paterson Orogen joined the West Australian Element with the South Australian and North Australian Elements, respectively, and are characterised by metamorphosed rocks of various facies. The Pinjarra Orogen, situated to the west of the Yilgarn-Pilbara block, contains granulite and amphibolite facies orthogneisses. In the Phanerozoic era, sedimentary cover occurred in various large and smaller basins in Western Australia. The West Australian Element, along with the adjoining orogens, is treated as the West Australian fractured rock province, primarily reliant on weathered and fractured zones for groundwater storage due to low permeability. These cratons and orogens have been exposed since the Precambrian or Late Palaeozoic era, experiencing substantial weathering and river valley development. Modern palaeovalleys are mainly infilled with Cenozoic sediments, while arid conditions have reduced active watercourses, leading to an abundance of Aeolian sand cover. Many of these palaeovalleys are no longer active as rivers but can still be identified topographically. Overall, the geological history of Australia reveals a complex and diverse landscape, with Western Australia playing a significant role in hosting some of the continent's oldest rocks and valuable mineral deposits.

  • This Wiso Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The Wiso Basin, a large intra-cratonic basin in the central Northern Territory, covers about 140,000 square kilometres and is part of the Centralian Superbasin. It is bounded by the Tennant and Tanami regions to the east and west, while a thrust fault separates it from the Arunta Region to the south. The basin adjoins the Georgina Basin in the southeast and joins the Daly and Georgina basins beneath the Cretaceous strata of the Carpentaria Basin in the north. The basin contains a relatively flat, undeformed succession of strata that gently dip towards the main depo-centre, the Lander Trough. About 80% of the basin consists of shallow middle Cambrian strata, while the remaining portion is within the Lander Trough, containing a diverse succession of Cambrian, Ordovician, and Devonian units. The depositional history and stratigraphy reveal that early Cambrian saw widespread basaltic volcanism, with the Antrim Plateau Volcanics forming the base layer and aquitard of the Wiso Basin. The middle Cambrian deposits include the Montejinni Limestone, the oldest sedimentary unit, followed by the Hooker Creek Formation and the Lothari Hills Sandstone. The uppermost Cambrian unit is the Point Wakefield beds. The Ordovician deposits consist of the Hansen River beds, primarily composed of fossiliferous sandstone and siltstone deposited in shallow marine environments. The Devonian unit capping the basin is the Lake Surprise Sandstone, found in the Lander Trough area, formed in shallow marine, shoreline, and fluvial environments during the Alice Springs Orogeny. Three main hypotheses have been proposed for the formation of the Lander Trough: a large crustal downwarp before thrusting of Paleoproterozoic rocks, the formation of a half-graben by faulting along the southern boundary, or the formation of two en-echelon synclines by vertical block movement. While the majority of the Wiso Basin consists of shallow middle Cambrian rocks, the Lander Trough presents a more varied stratigraphic sequence, holding potential for Neoproterozoic and early Cambrian rocks. However, further drilling is needed to verify this. The presence of similar units in neighbouring basins provides valuable insight into the basin's geological history and development.

  • This Money Shoal Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The Money Shoal Basin is a large passive margin basin in northern Australia, mainly located in the offshore Arafura Sea. Its sedimentary succession spans from the Mesozoic to the Cenozoic era, reaching a maximum thickness of 4,500 m in the northwest but thinner, less than 500 m, in central and eastern areas. The basin overlays the Neoproterozoic to Permian Arafura Basin and older Proterozoic rocks of the Pine Creek Orogen and McArthur Basin. It is bounded by the Bonaparte Basin to the west and the Carpentaria Basin to the east. The southern margin of the basin occurs onshore and is an erosional feature, although scattered remnant outliers of Money Shoal Basin rocks occur in isolated areas to the south and south-east of Darwin. The northern parts remain less explored, situated beyond Australia's maritime border with Indonesia. The basin's Mesozoic sediments were deposited during passive margin subsidence, and consequently remain relatively undeformed. Compressional tectonics were later initiated during the Cenozoic collision between the Indo-Australian plate and Southeast Asia, causing minor structural disruptions along the northwest margin of the Australian plate. Most of the sediments in the basin were deposited in shallow to marginal marine environments, with minor evidence for short-lived episodes of deltaic and fluvial deposition in some areas. The sedimentary packages in the offshore basin are divided into four groups: Troughton Group equivalent, Flamingo Group equivalent, Bathurst Island Group, and Woodbine Group equivalent. Onshore, the stratigraphic succession is limited to the Plover Formation equivalent, Bathurst Island Group, and the Eocene Van Diemen Sandstone. The Troughton Group extends from the Bonaparte Basin into western parts of the Money Shoal Basin, and chiefly consists of sandstone. The Flamingo Group, identified offshore, is considered equivalent to its Bonaparte Basin counterpart, characterized by sandstone and mudstone deposits, suggesting fluvial and deltaic settings. The Bathurst Island Group dominates onshore, composed mainly of fine-grained claystone, marl, and siltstone. The Woodbine Group is the uppermost unit, and is equivalent to the Woodbine Group of the Bonaparte Basin, consisting of Cenozoic deposits, primarily sandstone and claystone, indicating shallow marine and deltaic environments.

  • This Port Phillip-Westernport Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The Port Phillip and Westernport basins are small, shallow sedimentary basins located in south-central Victoria, formed during the Late Cretaceous rifting of Australia and Antarctica. They share similar stratigraphy with nearby basins. The Port Phillip Basin is bounded by the Selwyn and Rowsley Faults to the east and west, while the Heath Hill Fault marks the eastern boundary of the Westernport Basin. Both basins have pre-Cenozoic basement rocks comprising folded and faulted Paleozoic metasedimentary rocks and granites from the Lachlan Fold Belt. The Port Phillip Basin's stratigraphy includes Maastrichtian to Cenozoic sedimentary units with intercalated volcanic rocks. The main depocentres are the Sorrento Graben, Ballan Graben/Lal Lal Trough, and Parwan Trough. Notable formations are the Yaloak and Werribee formations, with coal-bearing strata and marine sediments. The Westernport Basin has coastal sediments and volcanic deposits from Paleocene to Holocene. It experienced marine transgressions and regressions due to sea-level fluctuations. Fault movements in the late Pliocene and early Pleistocene formed a fault-bounded depression centered on the Koo Wee Rup Plain. The main units are the Childers Formation, Older Volcanics, Yallock Formation, Sherwood Marl, and Baxter Sandstone. Both basins have Quaternary sediments, including Pleistocene eolian sand sequences, Holocene alluvial and paludal clays, and fluvial sediments in valleys and palaeovalleys. The Port Phillip Basin contains distinct phases of terrestrial and marine deposition, while the Westernport Basin has Eocene volcanism and marine sediments. These basins are important geological features in the region, with various formations representing millions of years of geological history.

  • This Murray Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The Murray Basin, a significant sedimentary basin in Australia, displays varying sediment thickness across its expanse, with the thickest layers concentrated in its central regions. The basin's geological evolution is characterised by distinct depositional phases. During the Paleocene to Eocene Renmark Group phase, sedimentary deposits encompass fluvial sands at the base, transitioning into paralic carbonaceous clay and lignite layers. These sediments indicate the shift from riverine to shallow marine environments, dating back to the Paleocene and Eocene periods. The Oligocene to Middle Miocene period encompasses the Ettrick Formation and Murray Group Limestone. The former includes marl, and the latter displays glauconitic grey-green marl and bryozoal limestone, revealing prevailing marine conditions during the Oligocene to Middle Miocene. In the Late Miocene to Early Pliocene Bookpurnong Formation, marine shelly dark grey clay and silt, previously known as the Bookpurnong Beds, coexist with Pliocene fluvial to marginal marine quartz sands (Loxton Sands), marking the transition back to terrestrial and nearshore marine settings. During the Late Pliocene to Pleistocene, the Blanchetown Clay, a substantial unit within Lake Bungunnia, signifies lacustrine phases. Overlying ferricretes in the central/eastern basin and the Norwest Bend Formation's oyster coquinas in the western region, the clay exhibits variable coloration and laminations. Lastly, the Pleistocene to Holocene phase witnesses river-induced reworking and erosion of underlying sediments, giving rise to the Shepparton and Coonambidgal formations. In the western Murray Basin, Cenozoic sedimentary rocks are relatively thin, typically measuring under 200-300 meters. The Renmark Trough area presents a maximum thickness of 600 meters.

  • This Ngalia Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The Ngalia Basin is an elongate, east-trending basin over 500 km long and 90 km wide. It occurs mostly in the Northern Territory, with limited occurrence in Western Australia. The Ngalia Basin is an intra-cratonic sedimentary basin in a structural downwarp formed by a faulted asymmetrical syncline. The basin began to form about 850 Ma, and contains a Neoproterozoic to Carboniferous sedimentary succession. Sedimentation ceased in response to the 450 to 300 Ma Alice Springs Orogeny. The maximum stratigraphic thickness of the Ngalia Basin is about 5000 m. The basin contains mainly arenaceous sedimentary rocks, with lesser fine-grained rock types and some carbonates. Fining upwards sedimentary cycles are commonly preserved and capped by calcite-cemented fine-grained sandstone and siltstone. Tectonic events disrupted deposition during basin evolution and led to at least ten unconformities. There are many disconformable contacts, with angular unconformities common in areas with abundant faulting. The upper-most arkosic sandstone formations in the Ngalia Basin are the Mount Eclipse Sandstone and the Kerridy Sandstone. These units have an aggregate thickness of several hundreds of metres and are the main aquifers within the Ngalia Basin sequence. There is some interstitial porosity, especially in the Mount Eclipse Sandstone, although joints and fissures associated with faulting provide significant secondary permeability. These aquifers provide good supplies of potable to brackish groundwater, and supply the community borefield at Yuendumu. The Ngalia Basin is almost entirely concealed by Cenozoic cover, including Palaeogene-Neogene palaeovalley, lake and alluvial fan sediment systems and Quaternary aeolian sands. Shallow aquifers with brackish to potable water occur in many palaeovalleys sediments overlying the basin.