<div>Reliable water availability is critical to supporting communities and industries such as mining, agriculture and tourism. In remote and arid areas such as in the Officer – Musgrave region of central Australia, groundwater is the only viable source of water for human and environmental use. Groundwater systems in remote regions such as the Musgrave Province are poorly understood due to sparse geoscientific data and few detailed scientific investigations. The Musgrave palaeovalley module will improve palaeovalley groundwater system understanding in the Musgrave Province and adjacent basins to identify potential water sources for communities in the region. This report summarises the state of knowledge for the region on the landscape, population, water use, geology and groundwater systems. An analysis of the current and potential future water needs under different development scenarios captures information on how water is used in an area covering three jurisdictions and several potentially competing land uses.</div><div>The Musgrave Palaeovalley study area is generally flat, low-lying desert country. The Musgrave, Petermann, Mann and Warburton ranges in the centre of the area are a significant change in elevation and surface materials, comprising rocky hills, slopes and mountains with up to 800&nbsp;m of relief above the sand plains. Vegetation is generally bare or sparse, with isolated pockets of grassy or woody shrub lands. Soils are typically Tenosols, Rudosols and Kandosols.</div><div><br></div><div>There are four main hydrogeological systems in the study area. These are the fractured and basement rocks, local Quaternary sediments regional sedimentary basins and palaeovalley aquifers. These systems are likely to be hydraulically connected. Within palaeovalleys, three main hydrostratigraphic units occur. The upper Garford Formation is a sandy unconfined aquifer with a clay rich base (lower Garford Formation) which acts as a partial aquitard where present. The Pidinga Formation represents a coarser sandy or gravelly channel base, which is partly confined by the lower Garford Formation aquitard. The aquifers are likely to be hydraulically connected on a regional scale. Further to the west, equivalent units are identified and named in palaeovalley systems on the Yilgarn Craton. </div><div><br></div><div>Groundwater is recharged by episodic, high-intensity rainfall events and mostly discharges via evapotranspiration. Recharge is higher around the ranges, and lower over the flatter sand plains. Palaeovalley aquifers likely receive some groundwater inflow from underlying basin systems and fractured rock systems. Regional groundwater movement is topographically controlled, moving from the ranges towards surrounding areas of lower elevation. In some palaeovalleys groundwater discharges at playa lakes. Water table gradients are very low. More groundwater isotope and tracer data is required to understand potential connectivity between basin, fractured rock and palaeovalley systems.</div><div>Groundwater quality is brackish to saline, although pockets of fresher groundwater occur close to recharge areas and within the deeper and coarse-grained Garford Formation. Groundwater resources generally require treatment prior to use Most groundwater in the region is suitable for stock use. </div><div><br></div><div>Existing palaeovalley mapping is restricted to inferring extents based on landscape position and mapped surface materials. Utilising higher resolution digital elevation models and more recently acquired remotely sensed data will refine mapped palaeovalley extents. Improving the modelling of the distribution and depth of palaeovalleys in greater detail across the region is best aided through interpretation of airborne electromagnetic (AEM) data.</div><div>Based on the successes of integrating AEM with other geoscientific data in South Australia, we have acquired 25,109 line km of new AEM across the WA and NT parts of our study area. We will integrate this data with reprocessed and inverted publicly available AEM data, existing borehole information, existing and newly acquired hydrochemical data, and new surface magnetic resonance data to model the three dimensional distribution of palaeovalleys in the study area. We will use these models and data as the basis for conceptualising the hydrogeology of the palaeovalley systems, and provide information back to local communities and decision-makers to inform water management decisions. The data will also provide valuable precompetitive information for future economic development in the region.</div><div><br></div>

Groundwater is an essential part of Darwin’s water supply mix, and is sourced from Howard East Borefield (HEB) and McMinns Borefield in the Koolpinyah Dolostone Aquifer (KDA), east of Darwin. Previous work suggested that electrical conductivity anomalies observed in airborne electromagnetic (AEM) data within 8 km of HEB may be caused by saline groundwater within the KDA that is separated from HEB by geological features that effectively compartmentalise the aquifer. Nevertheless, concerns grew that increased groundwater use may result in migration of saline groundwater towards HEB, which could compromise the groundwater resource. We collected hydrochemistry, including isotopes, time-series groundwater salinity and AEM data to better understand the complexities of the KDA. These data are presented here, along with a hydrodynamic analysis undertaken by the Northern Territory Department of Environment and Natural Resources, which shows that drawdown is occurring more rapidly from the NE of HEB and that dykes ~8 km NE of HEB act as barriers to groundwater flow. We show that groundwater sampled on the NE side of these dykes has a seawater composition. We use new AEM data to map the elevation of the top of unweathered dyke material and to characterise AEM conductors proximal to HEB. Our mapping reveals that the top of the unweathered portion of these dykes is commonly below sea level. We also show that AEM conductors proximal to HEB are more likely mineralised clays than saline groundwater within the aquifer. Drilling is required to confirm these results. Our findings contribute to building a robust conceptual understanding of the KDA and will inform future modelling of the groundwater system. <b>Citation:</b> Haiblen, A.M., Symington, N.J., Woltmann, M.J., Ray, A., Gow, L.J., Leplastrier, A. and McGrath, E.S.B., 2020. A multifaceted approach to investigating hydrogeological complexities in the Koolpinyah Dolostone Aquifer, Howard East, Northern Territory. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

This Maryborough-Nambour 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 Maryborough Basin is a half-graben intracratonic sag basin mainly filled with Early Cretaceous rocks, overlain by up to 100 m of Cenozoic sediments. It adjoins the older Nambour Basin to the south, comprising Triassic to Jurassic rocks. The boundary between the basins has shifted due to changes in sedimentary unit classifications, with the Cretaceous units now restricted to the Maryborough Basin and Jurassic and older units assigned to the Nambour Basin. Both basins are bounded to the west and unconformably overlies older Permian and Triassic rocks in the Gympie Province and Wandilla Province of the New England Orogen. In the south of the Nambour Basin, it partly overlaps with the Triassic Ipswich Basin. The Nambour Basin in the south is primarily composed of the Nambour Formation, with interbedded conglomerate, sandstone, siltstone, shale, and minor coal. Overlying this is the Landsborough Sandstone, a unit with continental, fluviatile sediments and a thickness of up to 450 m. In the north, the Duckinwilla Group contains the Myrtle Creek Sandstone and the Tiaro Coal Measures, which were formerly considered part of the Maryborough Basin but are now associated with the northern Nambour Basin. In contrast, the Maryborough Basin consists of three main Cretaceous units and an upper Cenozoic unit. The Grahams Creek Formation is the deepest, featuring terrestrial volcanic rocks, volcaniclastic sedimentary rocks, and minor pyroclastic rocks. The overlying Maryborough Formation was deposited in a continental environment with subsequent marine incursion and includes mudstone, siltstone, minor sandstone, limestone, conglomerate, and tuff. The upper Cretaceous unit is the Burrum Coal Measures, comprising interbedded sedimentary rocks deposited in fluvial to deltaic environments. The uppermost unit, the Eocene to Miocene Elliott Formation, includes sandstone, siltstone, conglomerate, and shale deposited in fluvial to deltaic environments. Cenozoic sediments overlying the Elliott Formation consist of Quaternary alluvium, coastal deposits, and sand islands like Fraser Island, influenced by eustatic sea level variations. Volcanic deposits and freshwater sediments also occur in some areas. Adjacent basins, such as the Clarence-Moreton Basin and Capricorn Basin, have stratigraphic correlations with the Maryborough Basin. The Oxley Basin lies to the south, overlying the Ipswich Basin. In summary, the Maryborough Basin and the older Nambour Basin exhibit distinct geological characteristics, with varying rock formations, ages, and sedimentary features, contributing to the diverse landscape of the region.

This Officer 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 Officer Basin is one of Australia's largest intra-cratonic sedimentary basins, spanning approximately 525,000 square kilometres. It contains a thick sedimentary sequence, ranging up to 10,000 m in depth, composed of rocks from the Neoproterozoic to Late Devonian periods. The basin features diverse depositional environments, including marine and non-marine siliclastic and carbonate units, evaporites, and minor volcanic deposits. The Neoproterozoic succession exhibits a range of depositional settings, including pro-delta to shelf, fluvial to shallow marine, lagoonal, glacial, and aeolian systems. The Cambrian to Ordovician sequence reveals evidence of fluvial, shallow marine, aeolian, sabkha to playa, and lacustrine settings. Volcanic rocks occur sporadically within the sequence, like the Cambrian Table Hill Volcanics in WA and the Neoproterozoic Cadlareena Volcanics in SA. The Officer Basin is considered a remnant of the larger Centralian Superbasin that formed during the Neoproterozoic, covering a vast region in central Australia. The Centralian Superbasin formed as a sag basin during the Tonian, accumulating fluvial, marine, and evaporitic sediments, followed by Neoproterozoic glacial deposits. The long-lasting Petermann Orogeny affected the earlier depositional systems, with extensive uplift along the northern margin of the basin leading to deposition of widespread fluvial and marine siliciclastic and carbonate sediments spanning the terminal Proterozoic to Late Cambrian. The Delamerian Orogeny renewed deposition and reactivated existing structures, and promoted extensive basaltic volcanism in the central and western regions of the basin. Later events are a poorly understood stage, though probably involved continued deposition until the Alice Springs Orogeny uplifted the region, terminating sedimentation in the Late Ordovician or Silurian. A suspected Late Devonian extensional event provided space for fluvial siliciclastic sediment deposition in the north-east. Today, the Officer Basin features four distinct structural zones: a marginal overthrust zone along the northern margin, a zone with rupturing by salt diapirs across the main depositional centre, a central thrusted zone, and a broad gently dipping shelf zone that shallows to the south.

This Southern 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. Crustal elements are crustal-scale geological regions primarily based on composite geophysical domains, each of which shows a distinctive pattern of magnetic and gravity anomalies. These elements generally relate to the basement, rather than the sedimentary basins. The South Australian Element comprises the Archean-Mesoproterozoic Gawler Craton and Paleo-Mesoproterozoic Curnamona Province, formed over billions of years through sedimentation, volcanism, magmatism, and metamorphism. The region experienced multiple continental-continent collisions, leading to the formation and breakup of supercontinents like Nuna and Rodinia, along with periods of extensional tectonism. Around 1,400 Ma, both the Gawler Craton and Curnamona Province were cratonised, and during the building of the Rodinia supercontinent (1,300-700 Ma), the present configuration of the region emerged. The area between the Gawler and Curnamona provinces contains Neoproterozoic to Holocene cover, including the Adelaide Superbasin, with the Barossa Complex as its basement, believed to be part of the Kimban Orogen. The breakup of Rodinia in the Neoproterozoic (830-600 Ma) resulted in mafic volcanism and extensional episodes, leading to the formation of the Adelaide Superbasin, characterized by marine rift and sag basins flanking the Gawler Craton and Curnamona Province. During the Mesozoic and Cenozoic, some tectonic structures were rejuvenated, while sedimentary cover obscured much of the now flatter terrain. Metamorphic facies in the region vary, with the Gawler and Curnamona provinces reaching granulite facies, while the Adelaide Superbasin achieved the amphibolite facies. The Gawler Craton contains rocks dating back to approximately 3,150 Ma, while the Curnamona Province contains rocks from 1,720 to 1,550 Ma. These ancient regions have undergone various deformation and metamorphic events but have remained relatively stable since around 1,450 Ma. The Adelaide Superbasin is a large sedimentary system formed during the Neoproterozoic to Cambrian, with distinct provinces. It started as an intracontinental rift system resulting from the breakup of Rodinia and transitioned into a passive margin basin in the southeast and a failed rift in the north. Later uplift and re-instigated rifting led to the deposition of thick Cambrian sediments overlying the Neoproterozoic rocks. Overlying basins include late Palaeozoic to Cenozoic formations, such as the Eromanga Basin and Lake Eyre Basin, which are not part of the assessment region but are adjacent to it.

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 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 Perth 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 Perth Basin is a complex geological region extending along Australia's southwest margin for about 1,300 km. It comprises sub-basins, troughs, terraces, and shelves, hosting sedimentary rocks with coal, oil, gas, and significant groundwater resources. Off the coast of Western Australia, it reaches depths of up to 4,500 m, while its onshore part extends up to 90 km inland. The basin is bounded by the Yilgarn Craton to the east, and the Carnarvon and Bremer basins to the north and south. The basin's history involves two main rifting phases in the Permian and Late Jurassic to Early Cretaceous, creating 15 sub-basins with varying sedimentary thickness due to compartmentalization and fault reactivation. The sedimentary succession mainly comprises fluviatile Permian to Early Cretaceous rocks over Archean and Proterozoic basement blocks. Differences exist between northern and southern sequences, with the south being continental and the north featuring marine deposits. During the Permian, faulting and clastic sedimentation dominated, with marine transgressions in the north and continental rocks in the south. The Triassic saw a similar pattern, with the southern succession being continental and the northern succession showing marine deposits. The Kockatea Shale became a primary hydrocarbon source. The Jurassic period witnessed marine incursions in the central basin, while the Late Jurassic experienced sea level regression and deposition of the Yarragadee Formation. The Cretaceous saw the formation of the Early Cretaceous Parmelia Group due to heavy tectonic activity. The southern basin had a marine transgression leading to the Warnbro Group's deposition with valuable groundwater resources. Post-Cretaceous, Cenozoic deposits covered the basin with varying thicknesses. Overall, the Perth Basin's geological history reveals a diverse sedimentary record with economic and resource significance.

This report presents key results from hydrogeological investigations at Alice Springs, completed as 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 Southern Stuart Corridor (SSC) project area within the Northern Territory extends in a north–south corridor from Tennant Creek to Alice Springs, encompassing four water control districts and a number of remote communities. Water allocation planning and agricultural expansion in the SSC is currently limited by a paucity of data and information regarding the volume and extent of groundwater resources and groundwater systems more generally. This includes recharge rates, surface water –groundwater connectivity, and the dependency of ecosystems on groundwater. Outside the proposed agricultural areas, the project includes numerous remote communities where there is a need to secure water supplies. Geoscience Australia, in partnership with the Northern Territory Department of Environment and Natural Resources and the Power and Water Corporation, undertook an extensive program of hydrogeological investigations between 2017 and 2019. Data acquisition included helicopter airborne electromagnetic (AEM) and magnetic data, investigative groundwater bore drilling, ground-based and downhole geophysical data (including nuclear magnetic resonance for mapping water content and induction conductivity/gamma for defining geological formations), and hydrochemistry for characterising groundwater systems. This report investigates the hydrogeology across the Alice Springs focus area, which includes the Roe Creek and proposed Rocky Hill borefields, where five hydrostratigraphic units were mapped based on AEM interpretation and borehole geophysical information. The mapping supports the presence of a syncline, with a gentle parabolic fold axis that plunges westward, and demonstrates that the main Siluro-Devonian Mereenie Sandstone and Ordovician Pacoota Sandstone aquifers are continuous from Roe Creek borefield to the Rocky Hill area. Areas with the highest potential for recharge to the Paleozoic strata are where Roe Creek or the Todd River directly overlie shallow subcrop of the aquifer units. Three potential recharge areas are identified: (1) Roe Creek borefield, (2) a 3 km stretch of Roe Creek immediately west of the proposed Rocky Hill borefield, and (3) the viticulture block to the east of Rocky Hill. Analysis of groundwater chemistry and regional hydrology suggests that the rainfall threshold for recharge of the Paleozoic aquifers is ~125 mm/month, and groundwater isotope data indicate that recharge occurs rapidly. The groundwaters have similar major ion chemistry, reflecting similar geology and suggesting that all of the Paleozoic aquifers in the focus area are connected to some degree. Groundwater extraction at Roe Creek borefield since the 1960s has led to the development of a cone of depression and a groundwater divide, which has gradually moved eastward and is now east of the proposed Rocky Hill borefield. The majority of the groundwater within the focus area is of good quality, with <1000 mg/L total dissolved salts (TDS). The brackish water (7000 mg/L TDS) further to the east of the proposed Rocky Hill borefield warrants further investigation to determine the potential risk of it being captured by the cone of depression following the development of this borefield. This study provides new insight to the hydrogeological understanding of the Alice Springs focus area. Specifically, this investigation demonstrates that the Roe Creek and proposed Rocky Hill borefields, and a nearby viticulture area are all extracting from the same aquifer system. This finding will inform the future management and security of the Alice Springs community water supply. New groundwater resource estimates and a water level monitoring scheme can be developed to support the management of this vital groundwater resource.

Geoscience Australia commissioned reprocessing of selected legacy 2D seismic data in the East Kimberley, onshore Bonaparte Basin as part of the Exploring for the Future (EFTF) program. Reprocessing of these data occurred between September 2017 and May 2018. Exploring for the Future (<a href="https://www.ga.gov.au/eftf/">https://www.ga.gov.au/eftf</a>) was a $100.5 million four-year (2016-20), Australian Government-funded program to provide a holistic picture of the potential mineral, energy and groundwater resources in northern Australia. The program has delivered new geoscience data, knowledge and decision support tools to support increased industry investment and sustainable economic development across the north. Groundwater is a critical resource that accounts for most water used across northern Australia. The groundwater component of the EFTF program focused on addressing groundwater resource knowledge gaps, to support future opportunities for economic development via irrigated agriculture, extractive industries and increased security of community water supplies. Through collaboration with State and Territory partners, the program undertook targeted regional investigations of groundwater systems and assessments of groundwater potential more broadly across the region. The program's activities, implemented by Geoscience Australia, involved application of innovative geoscience tools to collect, integrate and analyse a range of data. It includes geological and hydrogeological data, airborne and ground-based geophysical and hydrogeochemical surveys, remote sensing data as well as stratigraphic drilling. The new data and better understanding of groundwater systems also helps inform decision making about groundwater use to protect environmental and cultural assets. These outcomes strengthen investor confidence in resources and agricultural projects by de-risking groundwater in northern Australia. The package contains reprocessed data from ten surveys acquired between 1980 and 1997. In total 53 lines were reprocessed covering a fold area of approximately 618.9 line kilometres, with the objective to produce a modern industry standard 2D land seismic reflection dataset where possible from a selection of multiple legacy 2D data. The purpose of the reprocessing was twofold: 1) To image the near surface structural and stratigraphic configuration for linking to AEM data that is available in the Bonaparte Basin; and 2) To image the structure and stratigraphic architecture of the Paleozoic Bonaparte Basin. The dataset exhibits significant improvements in stack response in most of the reprocessed lines when final and legacy stacks were compared, especially in the shallow section. Optimum results were obtained from the noise attenuation workflows. A minimum processing flow was applied to BWA80, BWA81, and line BNT87-404 lines to avoid any signal leakage throughout the processing. Final data were delivered as minimum phase (care should be taken not to interpret zero crossings as geological boundaries), and final velocities produced a good match with the well checkshot velocities. The processing report from Down Under Geophysics is available for download with this release. Raw and processed data are available on request from <a href="mailto:clientservices@ga.gov.au&body=Ref: eCat 135578">clientservices@ga.gov.au</a> - Quote eCat# 135578. Processed stack SEG-Y files and ancillary data are available for download from this web page.