ENVIRONMENTAL SCIENCES
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Fresh groundwater stored in Australian coastal aquifers is an important resource for humans and the natural environment. Many Australian coastal aquifers are vulnerable to seawater intrusion (SWI)—the landward encroachment of sea water into coastal aquifers—which can significantly degrade water quality and reduce freshwater availability. The increasing demands for fresh water in coastal areas and the anticipated impacts of climate change (such as sea-level rise and variations in rainfall recharge) may result in increases in the incidence and severity of SWI. Comprehensive investigations of SWI are relatively uncommon and the extent of monitoring and investigations specific to SWI are highly variable across the nation. In response to the threat posed by SWI, Geoscience Australia and the National Centre for Groundwater Research and Training, in collaboration with state and territory water agencies, undertook a national-scale assessment of the vulnerability of coastal aquifers to SWI. This assessment identified the coastal groundwater resources that are most vulnerable to SWI, including future consequences of over-extraction, sea-level rise, and recharge–discharge variations associated with climate change. The study focused on assessing the vulnerability of coastal aquifers to the landward migration of the freshwater–saltwater interface, rather than surface waterbodies.
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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).
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<p>This package contains airborne electromagnetic (AEM) data from the "SkyTEM helicopter EM Howard East region" survey which was flown over Howard East region, Northern Territory during July - August 2017. The area is comprised of 2073.6 line kilometres in total. <p>The aim of the survey is to provide at a reconnaissance scale: <p>a) trends in regolith thickness and variability <p>b) variations in bedrock conductivity <p>c) conductivity of key bedrock (lithology related) conductive units under cover <p>d) the groundwater resource potential of the region <p>This report lists the SkyTEM system information and specifications relevant for this survey, and describes the processing carried out on the data. <p>Geoscience Australia commissioned the survey as part of the Exploring for the Future (EFTF) program. The EFTF program is led by Geoscience Australia (GA), in collaboration with the Geological Surveys of the Northern Territory, Queensland, South Australia and Western Australia, and is investigating the potential mineral, energy and groundwater resources in northern Australia and South Australia. The EFTF is a four-year $100.5 million investment by the Australian Government in driving the next generation of resource discoveries in northern Australia, boosting economic development across this region (https://www.ga.gov.au/eftf).
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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.
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This Surat 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 Surat Basin is a sedimentary basin with approximately 2500 m of clastic fluvial, estuarine, coastal plain, and shallow marine sedimentary rocks, including sandstone, siltstone, mudstone, and coal. Deposition occurred over six cycles from the Early Jurassic to the Cretaceous, influenced by eustatic sea-level changes. Each cycle lasted 10 to 20 million years, ending around the mid-Cretaceous. Bounded by the Auburn Arch to the northeast and the New England Orogen to the southeast, it connects to the Clarence-Moreton Basin through the Kumbarilla Ridge. The Central Fold Belt forms its southern edge, while Cenozoic uplift caused erosion in the north. The basin's architecture is influenced by pre-existing faults and folds in the underlying Bowen Basin and the nature of the basement rocks from underlying orogenic complexes. Notable features include the north-trending Mimosa Syncline and Boomi Trough, overlying the deeper Taroom Trough of the Bowen Basin and extending southwards. The Surat Basin overlies older Permian to Triassic sedimentary basins like the Bowen and Gunnedah Basins, unconformably resting on various older basement rock terranes, such as the Lachlan Orogen, New England Orogen, and Thomson Orogen. Several Palaeozoic basement highs mark its boundaries, including the Eulo-Nebine Ridge in the west and the Kumbarilla Ridge in the east. Paleogene to Neogene sediments, like those from the Glendower Formation, cover parts of the Surat Basin. Remnant pediments and Cenozoic palaeovalleys incised into the basin have added complexity to its geological history and may influence aquifer connections. Overall, the Surat Basin's geological history is characterized by millions of years of sedimentation, tectonic activity, and erosion, contributing to its geological diversity and economic significance as a source of natural resources, including coal and natural gas.
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This short video introduces liquefaction and its impact on buildings and other structures. Liquefaction is demonstrated using sand in a glass container and explains why it happens. The video contains images and short clips of liquefaction and introduces some ways engineers lessen the impact of earthquakes on buildings. The second half of the video includes instructions on how to make your own liquefaction demonstration and extend it into an inquiry activity.
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<div>In recent years Geoscience Australia has undertaken a successful continental scale validation program, targeting Landsat and Sentinel analysis ready data surface reflectance products. The field validation model used for this program successfully built on earlier studies and the measurement uncertainties associated with these protocols have been quantified and published. As a consequence, the Australian earth observation community was well-placed to respond to the United States Geological Survey (USGS) call for collaborators with the 2021 Landsat 8 (L8) and Landsat 9 (L9) 6 underfly. Despite a number of challenges, seven validation datasets were captured across five sites. As there was only a single 100% overlap transit across Australia and with the country in the midst of a strong La Niña climate cycle, it was decided to deploy teams to the two available overpasses with only 15% side lap. The validation sites encompassed rangelands, chenopod scrublands and a large inland lake. Apart from instrument problems at one site, good weather enabled the capture of high quality field data allowing for meaningful comparisons between the radiometric performance of L8 and L9, as well as the USGS and Australian Landsat analysis ready data processing models. Duplicate (cross calibration) spectral sampling at different sites provides evidence of the field protocol reliability, while the off-nadir view of L9 over the water site has been used to better compare the performance of different water and atmospheric correction (ATCOR) processing models. </div> <b>Citation: </b>Byrne, G.; Broomhall, M.; Walsh, A.J.; Thankappan, M.; Hay, E.; Li, F.; McAtee, B.; Garcia, R.; Anstee, J.; Kerrisk, G.; et al. Validating Digital Earth Australia NBART for the Landsat 9 Underfly of Landsat 8. <i>Remote Sens.</i> <b>2024</b>, 16, 1233. https://doi.org/10.3390/rs16071233
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<div>This record one in a series of reports detailing the geochemical and mineralogical results of sampling collected at mine waste sites across Australia as part of Geoscience Australia's Exploring for the Future program. It presents new data and information regarding the tenor rare earth elements, ore commodities (lead, zinc and silver) and other trace metals, at the Cannington silver and lead mine located in Queensland’s Northwest Minerals Province.</div><div><br></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.</div><div><br></div>
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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
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The Trusted Environmental and Geological Information (TEGI) program will provide high-quality data to help governments, industry and communities make informed decisions about prospective basins, leading to improved outcomes for the Australian environment.