GEOPHYSICS
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This data collection is comprised of radiometric (gamma-ray spectrometric) surveys acquired across Australia by Commonwealth, State and Northern Territory governments and the private sector with project management and quality control undertaken by Geoscience Australia. The radiometric method measures naturally occurring radioactivity arising from gamma-rays. In particular, the method is able to identify the presence of the radioactive isotopes potassium (K), uranium (U) and thorium (Th). The measured radioactivity is then converted into concentrations of the radioelements K, U and Th in the ground. Radiometric surveys have a limited ability to see into the subsurface with the measured radioactivity originating from top few centimetres of the ground. These surveys are primarily used as a geological mapping tool as changes in rock and soil type are often accompanied by changes in the concentrations of the radioactive isotopes of K, U and Th. The method is also capable of directly detecting mineral deposits. For example, K alteration can be detected using the radiometric method and is often associated with hydrothermal ore deposits. Similarly, the method is also used for U and Th exploration, heat flow studies, and environmental mapping purposes such as characterising surface drainage features. The instrument used in radiometric surveys is a gamma-ray spectrometer. This instrument measures the number of radioactive emissions (measured in counts per second) and their energies (measured in electron volts (eV)). Radiometric data are simultaneously acquired with magnetic data during airborne surveys and are a non-invasive method for investigating near-surface geology and regolith.
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The GEOPHYS_SURV database describes geophysical surveys (air, land, and marine), the datasets derived from those surveys, and the methods used for delivery of those datasets. The database includes metadata for all surveys conducted or managed by Geoscience Australia and its predecessor agencies, as well as data and surveys from State and Territory geological survey agencies.
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The discovery of strategically located salt structures, which meet the requirements for geological storage of hydrogen, is crucial to meeting Australia’s ambitions to become a major hydrogen producer, user and exporter. The use of the AusAEM airborne electromagnetic (AEM) survey’s conductivity sections, integrated with multidisciplinary geoscientific datasets, provides an excellent tool for investigating the near-surface effects of salt-related structures, and contributes to assessment of their potential for underground geological hydrogen storage. Currently known salt in the Canning Basin includes the Mallowa and Minjoo salt units. The Mallowa Salt is 600-800 m thick over an area of 150 × 200 km, where it lies within the depth range prospective for hydrogen storage (500-1800 m below surface), whereas the underlying Minjoo Salt is generally less than 100 m thick within its much smaller prospective depth zone. The modelled AEM sections penetrate to ~500 m from the surface, however, the salt rarely reaches this level. We therefore investigate the shallow stratigraphy of the AEM sections for evidence of the presence of underlying salt or for the influence of salt movement evident by disruption of near-surface electrically conductive horizons. These horizons occur in several stratigraphic units, mainly of Carboniferous to Cretaceous age. Only a few examples of localised folding/faulting have been noted in the shallow conductive stratigraphy that have potentially formed above isolated salt domes. Distinct zones of disruption within the shallow conductive stratigraphy generally occur along the margins of the present-day salt depocentre, resulting from dissolution and movement of salt during several stages. This study demonstrates the potential AEM has to assist in mapping salt-related structures, with implications for geological storage of hydrogen. In addition, this study produces a regional near-surface multilayered chronostratigraphic interpretation, which contributes to constructing a 3D national geological architecture, in support of environmental management, hazard mapping and resource exploration. <b>Citation: </b>Connors K. A., Wong S. C. T., Vilhena J. F. M., Rees S. W. & Feitz A. J., 2022. Canning Basin AusAEM interpretation: multilayered chronostratigraphic mapping and investigating hydrogen storage potential. In: Czarnota, K (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/146376
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Nuclear Magnetic Resonance data may be used to estimate physical properties such as water content, NMR relaxation time, and porosity of formations penetrated by boreholes. These data were acquired as part of the Exploring for the Future (EFTF) program at field sites within the East Kimberley and Southern Stuart Corridor field areas.
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This animation shows how Airborne Electromagnetic Surveys Work, when conducted by a rotary wing (helicopter) aircraft. It is part of a series of Field Activity Technique Engagement Animations. The target audience are the communities that are impacted by our data acquisition activities. There is no sound or voice over. The 2D animation includes a simplified view of what AEM equipment looks like, what the equipment measures and how the survey works.
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This data collection are comprised of magnetic surveys acquired across Australia by Commonwealth, State and Northern Territory governments and the private sector with project management and quality control undertaken by Geoscience Australia. Magnetic surveying is a geophysical method for measuring the intensity (or strength) of the Earth's magnetic field, which includes the fields associated with the Earth's core and the magnetism of rocks in the Earth's crust. Measuring the magnetism of rocks, in particular, provides a means for the direct detection of several different types of mineral deposits and for geological mapping. The magnetism of rocks depends on the volume, orientation and distribution of their constituent magnetic minerals (namely magnetite, monoclinic pyrrhotite, maghaemite and ilmenite). The instrument used in magnetic surveys is a magnetometer, which can measure the intensity of the magnetic field in nanoteslas (nT). Magnetic surveys in this collection have been acquired using aircraft or ship-mounted magnetometers and are a non-invasive method for investigating subsurface geology.
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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.
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A SkyTEM airborne electromagnetic (AEM) survey was flown during the period 09 to 24 August 2017 in the Daly River Region, Northern Territory, Australia. The area is located in the 1:250000 map sheets, SD52-08 (Pine Creek), SD52-12 (Fergusson River), SD52-16 (Delamere), SD53-09 (Katherine) and SD53-13 (Larrimah) south-southeast of the city of Darwin. Approximately 3379 line kilometres of TEM and magnetic data were acquired. The projected grid coordinates have been supplied in GDA94 MGA Zone 52. The aim of the survey is to provide geophysical information to support investigations of the regional groundwater system, identify regional groundwater sources and mitigate risk in irrigation development. It will provide data to allow for the modelling of the following at a reconnaissance scale: a) trends in regolith thickness and variability b) variations in bedrock conductivity c) conductivity of key bedrock (lithology related) conductive units under cover d) the groundwater resource potential of the region
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<p>Eight hundred and seventy two km of gravity and deep crustal reflection data were collected for the Kidson Sub-Basin 2D seismic survey along a single transect: 18GA-KB1 during June to August 2018. <p>The purpose of the survey was to image basin and basement structures of the Kidson Sub-Basin of the onshore Canning Basin, and extending across the Paterson Orogen and on to the eastern margin of the Pilbara Craton. <p>The new data will help geological interpretations to determine the stratigraphy, lateral extent and stratigraphic relationships of the basin and adjoining terranes, and an assessment of the region for its oil and gas and mineral potential. <p>The project is a collaboration between Geoscience Australia (GA) and the Geological Survey of Western Australia (GSWA) and was funded by the Australian Government's Exploring for the Future program and the Western Australian Government's Exploration Incentive Scheme (EIS). <p>Raw data for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 128284
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<p>The Northern Territory Geological Survey (NTGS) designed the Mount Peake-Crawford survey to provide high resolution magnetic, radiometric and elevation data in the area. It is anticipated that the data from the survey would help attract explorers into ‘greenfield’ terranes and contribute to the discovery of the next generation of major mineral and energy deposits in the Northern Territory. A total of 120,000 line km of regional data (200m line spacing) and additional infill data (100m line spacing), flown at 60m flight height were acquired during the survey between July and October 2019. The survey was managed by Geoscience Australia. <p>Various grids were produced from the Mount Peake-Crawford Airborne Magnetic and Radiometric Survey dataset and simultaneously merged into a single grid file. The final grid retains all of the information from the input data and is levelled to the national map compilations produced by Geoscience Australia. The merged grids have a cell size of 20m. <p>The following merged grids are available in this download: <p>• Laser-derived digital elevation model grids (m). Height relative to the Australian Height Datum. <p>• Radar-derived digital elevation model grids (m). Height relative to the Australian Height Datum. <p>• Total magnetic intensity grid (nT). <p>• Total magnetic intensity grid with variable reduction to the pole applied (nT). <p>• Total magnetic intensity grid with variable reduction to the pole and first vertical derivative applied (nT/m). <p>• NASVD-filtered potassium concentration grid (%). <p>• NASVD-filtered thorium concentration grid (ppm). <p>• NASVD-filtered uranium concentration grid (ppm).