From 1 - 10 / 270
  • Digital Elevation Model data record the terrain height variations from the processed point-located data recorded on an airborne geophysical survey. The aircraft altimeter data records the height of the aircraft above the ground and the aircraft GPS records the height of the aircraft above the ellipsoid. Subtracting the two values enables the height of the terrain beneath the aircraft relative to the ellipsoid to be calculated. This ellipsoidal terrain height is corrected for the variation between the ellipsoid and the geoid (the n-value correction) to produce terrain heights relative to sea level.

  • Digital Elevation Model data record the terrain height variations from the processed point-located data recorded on an airborne geophysical survey.  The aircraft altimeter data records the height of the aircraft above the ground and the aircraft GPS records the height of the aircraft above the ellipsoid.  Subtracting the two values enables the height of the terrain beneath the aircraft relative to the ellipsoid to be calculated.  This ellipsoidal terrain height is corrected for the variation between the ellipsoid and the geoid (the n-value correction) to produce terrain heights relative to sea level.

  • Gravity data measures small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This West_Musgrave_Complete_Gravity_Bouguer_Anomaly_geodetic.nc grid is a complete Bouguer anomaly grid for the West Musgrave Gravity 2008 WA survey. This gravity survey was acquired under the project No. 200860 for the geological survey of WA. The grid has a cell size of 0.0046 degrees (approximately 480m). A total of 4027 gravity stations were acquired to produce this grid.

  • A series of regional pilot geochemical survey projects have been carried out in Australia over recent years. These pilot projects targeted a number of landscape and climate settings that are challenging for geochemical mapping, and applied increasingly lower sampling densities, from c. 1 site/300 km2 to c. 1 site/ 2100 km2. Selected results are presented from pilot geochemical surveys in the Riverina, Gawler and Thomson regions, as well as results from modelling aimed at testing the robustness of ultra-low sampling densities in Australia. The salient conclusions are that: (1) geochemical surveys sampling surface and near-surface transported regolith are capable of identifying major lithologies and mineralization below the cover; and (2) a sampling strategy targeting outlet sediments of large catchments allows the application of ultra-low sampling densities in Australia. These findings overcome the main hurdles met by earlier attempts at designing a nation-wide geochemical survey. The strategy for the resulting National Geochemical Survey of Australia (NGSA) project, recently approved for funding under the Australian Government's Onshore Energy Security Initiative, is outlined. By 2011, the NGSA will produce a publicly available multi-element, internally consistent and state-of-the-art regolith geochemical database and atlas to support decision-makers.

  • Gravity anomaly map of the Australian Region 3rd edition. This map is derived from an image which combined onshore Bouguer gravity anomaly and offshore freeair anomaly values. Onshore Bouguer gravity anomalies were calculated from over 1.4 million observations held in the the Australian National Gravity Database. Offshore freeair anomaly data were derived from satellite altimetry data available from Scripps Institution of Oceanography. This data is used to study the tectonic structure of Australia by mapping variations in the earth's gravimetric field. The 'hotter colours' (eg red) show areas of stronger gravity field and the 'cooler colours' (eg dark blue) show areas of weaker gravity field. Gravity data used to produce the Gravity Anomaly Map of the Australian Region are available for free download via the Geophysical Archive Data Delivery System (GADDS).

  • To assist the mining industry during the current buoyant times of historically high nickel and platinum-group element prices, Geoscience Australia has produced two web-based map sheets (at 1:5 million and 1:10 million scales) that show the spatial distribution of Proterozoic (2500 Ma to 545 Ma) mafic-ultramafic magmatic events in Australia. The maps illustrate for the first time, the continental extent and age relationships of Proterozoic mafic and ultramafic rocks and their associated mineral deposits. These rocks have been assigned to thirty Magmatic Events (ME) that range in age from the Early Palaeoproterozoic ~2455 Ma (ME 1) to the Early Cambrian ~520 Ma (ME 30). Resource package contains: - Australian Proterozoic Mafic-Ultramafic Magmatic Events: Map Sheets 1 and 2 - Guide to Using the Australian Proterozoic Mafic-Ultramafic Magmatic Events Map - Spreadsheets of data that support the maps - A time series animation summarising all the mafic-ultramafic magmatic events

  • Multibeam sonar mapping, drill cores and underwater video data have confirmed the existence of a previously unknown reef province in the Gulf of Carpentaria, Australia. Seven reefs, comprised of coral limestone that support living corals have been mapped so far and as many as 50 other reefs may exist in the region. U/Th ages show that reef growth commenced shortly after limestone pedestals were submerged by rising sea level around 10.5 kyr BP, making them the oldest reefs known in Australia. Reef growth persisted for ~2.0 kyr but it had ceased at most locations by ~8.0 kyr BP. Measurements of reef growth rates (0.95 to 4 m kyr-1), indicate that the reefs were unable to keep pace with contemporaneous rapid sea level rise (>10 m kyr-1), which is consistent with a 'give up' reef growth history. Core samples from reef platforms demonstrate that Pleistocene limestone is exposed in depths of 27 and 30 m below present mean sea level. These depths represent regionally significant phases of reef growth during a prolonged sea level still stand. We conclude that the reefs are therefore mostly relict features, whose major phase of growth and development relates to an earlier, pre-Holocene sea level stillstand.

  • The Mingary 1:100,000 regolith landform map illustrates the distribution of regolith materials and the landforms on which they occur, described using a hybrid mapping scheme based on lithostratigraphic units and the regolith which occurs over them developed by the Department of Primary Industries, South Australia

  • This short movie tells the story of the making of the <a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&catno=70791">Radiometric Map of Australia</a>. Scientists at Geoscience Australia have, for the first time, been able to produce a map of Australia showing the distribution of the radioactive elements Potassium, Uranium and Thorium across the continent using airborne geophysical data that have taken over 30 years to acquire. This movie explores the questions: What have we done that is special; Why is it special; How did it all start - history; What is gamma-ray spectrometry; What was the problem encountered and how was it solved; Who uses the map. Flash movie is 17.7MB, 5 Minutes.

  • The Arnhem Bay-Blue Mud Bay 1:250,000 regolith-landform map illustrates the distribution of regolith materials and the landforms on which they occur, illustrates using the RTMAP scheme developed by Geoscience Australia