From 1 - 10 / 93
  • The values and distribution patterns of the strontium (Sr) isotope ratio 87Sr/86Sr in Earth surface materials is of use in the geological, environmental and social sciences. Ultimately, the 87Sr/86Sr ratio of any mineral or biological material reflects its value in the rock that is the parent material to the local soil and everything that lives in and on it. In Australia, there are few large-scale surveys of 87Sr/86Sr available, and here we report on a new, low-density dataset using 112 catchment outlet (floodplain) sediment samples covering 529,000 km2 of inland southeastern Australia (South Australia, New South Wales, Victoria). The coarse (<2 mm) fraction of bottom sediment samples (depth ~0.6-0.8 m) from the National Geochemical Survey of Australia were fully digested before Sr separation by chromatography and 87Sr/86Sr determination by multicollector-inductively coupled plasma-mass spectrometry. The results show a wide range of 87Sr/86Sr values from a minimum of 0.7089 to a maximum of 0.7511 (range 0.0422). The median 87Sr/86Sr (± robust standard deviation) is 0.7199 (± 0.0112), and the mean (± standard deviation) is 0.7220 (± 0.0106). The spatial patterns of the Sr isoscape observed are described and attributed to various geological sources and processes. Of note are the elevated (radiogenic) values (≥~0.7270; top quartile) contributed by (1) the Palaeozoic sedimentary country rock and (mostly felsic) igneous intrusions of the Lachlan geological region to the east of the study area; (2) the Palaeoproterozoic metamorphic rocks of the central Broken Hill region; both these sources contribute fluvial sediments into the study area; and (3) the Proterozoic to Palaeozoic rocks of the Kanmantoo, Adelaide, Gawler and Painter geological regions to the west of the area; these sources contribute radiogenic material to the region mostly by aeolian processes. Regions of low 87Sr/86Sr (≤~0.7130; bottom quartile) belong mainly to (1) a few central Murray Basin catchments; (2) some Darling Basin catchments in the northeast; and (3) a few Eromanga geological region-influenced catchments in the northwest of the study area. The new spatial dataset is publicly available through the Geoscience Australia portal (https://portal.ga.gov.au/restore/cd686f2d-c87b-41b8-8c4b-ca8af531ae7e).

  • Hydrochemistry data for Australian groundwater, including field and laboratory measurements of chemical parameters (electrical conductivity (EC), potential of hydrogen (pH), redox potential, and dissolved oxygen), major and minor ions, trace elements, nutrients, pesticides, isotopes and organic chemicals. < <b>Value: </b>The chemical properties of groundwater are key parameters to understand groundwater systems and their functions. Groundwater chemistry information includes the ionic and isotopic composition of the water, representing the gases and solids that are dissolved in it. Hydrochemistry data is used to understand the source, flow, and interactions of groundwater samples with surface water and geological units, providing insight into aquifer characteristics. Hydrochemistry information is key to determining the quality of groundwater resources for societal, agricultural, industrial and environmental applications. Insights from hydrochemical analyses can be used to assess a groundwater resource, the impact of land use changes, irrigation and groundwater extraction on regional groundwater quality and quantity, assess prospective mineral exploration targets, and determine how groundwater interacts with surface water in streams and lakes. <b>Scope: </b>The database was inaugurated in 2016 with hydrochemical data collected over the Australian landmass by Geoscience Australia and its predecessors, and has expanded with regional and national data. It has been in the custodianship of the hydrochemists in Geoscience Australia's Minerals, Energy and Groundwater Division and its predecessors. Explore the <b>Geoscience Australia portal - https://portal.ga.gov.au/</b>

  • This report presents key results from hydrogeological investigations in the Tennant Creek region, 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 EFTF Southern Stuart Corridor (SSC) Project area is located in the Northern Territory and 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 limited by a paucity of data and information regarding the volume and extent of groundwater resources and groundwater systems more generally. Geoscience Australia, in partnership with the Northern Territory Department of Environment and Natural Resources and Power and Water Corporation, undertook an extensive program of hydrogeological investigations in the SSC Project area between 2017 and 2019. Data acquisition included; helicopter airborne electromagnetic (AEM) and magnetic data; water bore drilling; ground-based and downhole geophysical data for mapping water content and defining geological formations; hydrochemistry for characterising groundwater systems; and landscape assessment to identify potential managed aquifer recharge (MAR) targets. This report focuses on the Tennant Creek region—part of the Barkly region of the Northern Territory. Investigations in this region utilised existing geological and geophysical data and information, which were applied in the interpretation and integration of AEM and ground-based geophysical data, as well as existing and newly acquired groundwater hydrochemical and isotope data. The AEM and borehole lithological data reveal the highly weathered (decomposed) nature of the geology, which is reflected in the hydrochemistry. These data offer revised parameters, such as lower bulk electrical conductivity values and increased potential aquifer volumes, for improved modelling of local groundwater systems. In many instances the groundwater is shown to be young and of relatively good quality (salinity generally <1000 mg/L total dissolved solids), with evidence that parts of the system are rapidly recharged by large rainfall events. The exception to this is in the Wiso Basin to the west of Tennant Creek. Here lower quality groundwater occurs extensively in the upper 100 m below ground level, but this may sit above potentially potable groundwater and that possibility should be investigated further. Faults are demonstrated to have significantly influenced the occurrence and distribution of weathered rocks and of groundwater, with implications for groundwater storage and movement. Previously unrecognised faults in the existing borefield areas should be investigated for their potential role in compartmentalising groundwater. Additionally a previously unrecognised sub-basin proximal to Tennant Creek may have potential as a groundwater resource or a target for MAR. This study has improved understanding of the quantity and character of existing groundwater resources in the region and identified a managed aquifer recharge target and potential new groundwater resources. The outcomes of the study support informed water management decisions and improved water security for communities; providing a basis for future economic investment and protection of environmental and cultural values in the Tennant Creek and broader Barkly region. Data and information related to the project are summarised in the conclusions of this report and are accessible via the EFTF portal (https://portal.ga.gov.au/).

  • This Otway 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 Otway Basin is an elongated sedimentary basin located on the south-east continental margin of Australia. Covering approximately 150,000 square kilometres and stretching about 500 km from South Australia's Cape Jaffa to Victoria's Port Phillip Bay and Tasmania's north-west, most of the basin is offshore, with a smaller portion onshore. Geological studies of the Otway Basin have primarily focused on its hydrocarbon prospectivity, examining thick Cretaceous aged rocks both onshore and offshore. However, the shallower onshore sedimentary units are more relevant from a groundwater perspective. The basin's formation began with rifting between the Australian and Antarctic plates during the Late Jurassic, leading to regional subsidence and the development of the elongated sedimentary basin. Following the Cretaceous plate breakup, a passive margin basin formed, which subsequently underwent basin inversion, reverse faulting, and folding, interspersed with extensional periods and normal faulting. This complex evolution, combined with sea level variations and volcanic activity, resulted in numerous sedimentary cycles. The sedimentary succession in the basin comprises non-marine sediments and volcanic rocks from the Jurassic and early Cretaceous, with a period of tectonic compression interrupting sedimentation during the mid-Cretaceous. The late Cretaceous and Cenozoic sedimentary and volcanic rocks form the primary groundwater-bearing aquifers of the basin, with various sedimentary environments developing in the Neogene and Quaternary. The basin's structural geology is intricate, with numerous basement highs, sub-basins, troughs, and embayments. Fault systems are prevalent, separating tectonic blocks and potentially influencing groundwater flow, offering conduits for inter-aquifer connectivity. Overall, the Otway Basin's geological history has shaped its hydrocarbon potential and groundwater resources, making it an essential area for ongoing research and exploration in Australia's geological landscape.

  • Wetlands around the world provide crucial ecosystem services and are under increasing pressure from multiple sources including climate change, changing flow and flooding regimes, and encroaching human populations. The Landsat satellite imagery archive provides a unique observational record of how wetlands have responded to these impacts during the last three decades. Information stored within this archive has historically been difficult to access due to its petabyte-scale and the challenges in converting Earth observation data into biophysical measurements that can be interpreted by wetland ecologists and catchment managers. This paper introduces the Wetlands Insight Tool (WIT), a workflow that generates WIT plots that present a multidecadal view of the biophysical cover types contained within individual Australian wetlands. The WIT workflow summarises Earth observation data over 35 years at 30 m resolution within a user-defined wetland boundary to produce a time-series plot (WIT plot) of the percentage of the wetland covered by open water, areas of water mixed with vegetation (‘wet’), green vegetation, dry vegetation, and bare soil. We compare these WIT plots with documented changes that have occurred in floodplain shrublands, alpine peat wetlands, and lacustrine and palustrine wetlands, demonstrating the power of satellite observations to supplement ground-based data collection in a diverse range of wetland types. The use of WIT plots to observe and manage wetlands enables improved evidence-based decision making. <b>Citation:</b> Dunn, B., Ai, E., Alger, M.J. et al. Wetlands Insight Tool: Characterising the Surface Water and Vegetation Cover Dynamics of Individual Wetlands Using Multidecadal Landsat Satellite Data. <i>Wetlands</i><b> 43</b>, 37 (2023). https://doi.org/10.1007/s13157-023-01682-7

  • HiQGA is a general purpose software package for spatial statistical inference, geophysical forward modeling, Bayesian inference and inversion (both deterministic and probabilistic). It includes readily usable geophysical forward operators for airborne electromagnetics (AEM), controlled-source electromagnetics (CSEM) and magnetotellurics (MT). Physics-independent inversion frameworks are provided for probabilistic reversible-jump Markov chain Monte Carlo (rj-MCMC) inversions, with models parametrised by Gaussian processes (Ray and Myer, 2019), as well as deterministic inversions with an "Occam inversion" framework (Constable et al., 1987). In development software for EFTF since 2020

  • 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 South-east 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. Groundwater in Australia's fractured rock aquifers is stored in fractures, joints, bedding planes, and cavities within the rock mass, comprising about 40% of the country's groundwater. Much of this water can be utilized for irrigation, town water supplies, stock watering, and domestic use, based on state regulations. Fractured systems account for approximately 33% of all bores in Australia but contribute to only 10% of total extraction due to variable groundwater yield. Quantifying groundwater movement in fractured rock systems is challenging, as it depends on the distribution of major fractures. Groundwater flow direction is more influenced by the orientation of fractures than hydraulic head distribution. Recharge in fractured rock aquifers is typically localized and intermediate. In Eastern Australia, New South Wales' Lachlan Orogen, which extends from central and eastern New South Wales to Victoria and Tasmania, is a significant region with diverse lithological units, including deep marine turbidites, shallow marine to sub-areal sediments, extensive granite bodies, and volcano-intrusive complexes. This region contains various mineral deposits, such as orogenic gold, volcanic-hosted massive sulphide, sediment-hosted Cu-Au, porphyry Au-Cu, and granite-related Sn. Note: The study does not include additional Orogens in the east (New England) and west (Thomson and Delamerian). The Delamerian Orogen is present throughout western Tasmania.

  • This Galilee 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. This Galilee 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 Galilee Basin is a large intracratonic sedimentary basin in central Queensland. The basin contains a variably thick sequence of Late Carboniferous to Middle Triassic clastic sedimentary rocks dominated by laterally extensive sandstone, mudstone and coal. These rocks were mostly deposited in non-marine environments (rivers, swamps and lakes), although there is minor evidence for marginal marine settings such as deltas and estuaries. Sedimentation did not occur continuously across the approximately 90 million year history of basin development, and intervals of episodic compression, uplift and erosion were marked by distinct depositional breaks. Over much of the surface area of the Galilee Basin the main aquifers targeted for groundwater extraction occur in the younger rocks and sediments that overlie the deeper sequence of the Galilee Basin. The primary aquifers that supply groundwater in this region are those of the Eromanga Basin, as well as more localised deposits of Cenozoic alluvium. However, in the central-east and north-east of the Galilee Basin, the Carboniferous to Triassic rocks occur at or close to surface and several aquifer units supply significant volumes of groundwater to support pastoral and town water supplies, as well as being the water source for several spring complexes. The three main groundwater systems identified in the Galilee Basin occur in the 1. Clematis Group aquifer, 2. partial aquifer of the upper Permian coal measures (including the Betts Creek beds and Colinlea Sandstone), and 3. aquifers of the basal Joe Joe Group. The main hydrogeological units that confine regional groundwater flow in the Galilee Basin are (from upper- to lower-most) the Moolayember Formation, Rewan Formation, Jochmus Formation and Jericho Formation. However, some bores may tap local groundwater resources within these regional aquitards in areas where they outcrop or occur close to surface. Such areas of localised partial aquifer potential may be due in part to enhanced groundwater storage due to weathering and fracturing.

  • This Clarence-Moreton 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 formation of the Clarence-Moreton Basin initiated during the Middle Triassic due to tectonic extension. This was followed by a prolonged period of thermal cooling and relaxation throughout the Late Triassic to the Cretaceous. Deposition of a non-marine sedimentary succession occurred during this time, with the Clarence-Moreton Basin now estimated to contain a sedimentary thickness of up to 4000 m. There were three main depositional centres within the basin, and these are known as the Cecil Plain Sub-basin, Laidley Sub-basin and Logan Sub-basin. The Clarence-Moreton Basin sediments were originally deposited in non-marine environments by predominantly northward flowing rivers in a relatively humid climate. The sedimentary sequences are dominated by a mixed assemblage of sandstone, siltstone, mudstone, conglomerate and coal. Changing environmental conditions due to various tectonic events resulted in deposition of interbedded sequences of fluvial, paludal (swamp) and lacustrine deposits. Within the Clarence-Moreton Basin, coal has been mined primarily from the Jurassic Walloon Coal Measures, including for the existing mines at Commodore and New Acland. However, coal deposits also occur in other units, such as the Grafton Formation, Orara Formation, Bundamba Group, Ipswich Coal Measures, and Nymboida Coal Measures. Overlying the Clarence-Moreton Basin in various locations are Paleogene and Neogene volcanic rocks, such as the Main Range Volcanics and Lamington Volcanics. The thickness of these volcanic rocks is typically several hundred metres, although the maximum thickness of the Main Range Volcanics is about 900 m. Quaternary sediments including alluvial, colluvial and coastal deposits also occur in places above the older rocks of the Clarence-Moreton Basin.