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  • In 2007 a TEMPEST time domain airborne electromagnetic (AEM) survey was flown over the Lower Macquarie River catchment in central West New South Wales, Australia. The survey was commissioned by the Australian Government Department of Agriculture, Fisheries and Forestry through the Bureau of Rural Sciences and funded under the National Action Plan for Salinity and Water Quality. The data are being publicly released through Geoscience Australia's National Airborne Geophysics Database (Project #1140).

  • 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.

  • In 2007 a RESOLVE frequency domain airborne electromagnetic survey was flown over and adjacent to a stretch of the River Murray along the western border separating Victoria and New South Wales, Australia. The survey was commissioned by the Australian Government Department of Agriculture, Fisheries and Forestry through the Bureau of Rural Sciences and funded under the National Action Plan for Salinity and Water Quality.

  • 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_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.

  • 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 p200741_Cooper_Basin_South_BA267_VD_geodetic.nc grid is a first vertical derivative of the Bouguer anomaly grid for the Cooper Basin South Gravity Survey, Queensland 2007 survey. This gravity survey was acquired under the project No. 200741 for the geological survey of QLD. The grid has a cell size of 0.0075 degrees (approximately 790m). A total of 9216 gravity stations were acquired to produce the original grid. A Fast Fourier Transform (FFT) process was applied to the original grid to calculate the first vertical derivative grid.

  • 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 Charters_Towers_complete_Bouguer_geodetic_2x2.nc grid is a complete Bouguer anomaly grid for the Charters Towers Gravity Survey, Qld, 2008 survey. This gravity survey was acquired under the project No. 200740 for the geological survey of QLD. The grid has a cell size of 0.0037 degrees (approximately 400m). A total of 14161 gravity stations were acquired to produce this grid.

  • 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 p200741_Cooper_Basin_South_CompleteBA267_geodetic.nc grid is a complete Bouguer anomaly grid for the Cooper Basin South Gravity Survey, Queensland 2007 survey. This gravity survey was acquired under the project No. 200741 for the geological survey of QLD. The grid has a cell size of 0.0075 degrees (approximately 790m). A total of 9216 gravity stations were acquired to produce this grid.

  • Widespread seagrass dieback in central Torres Strait, Australia has been anecdotally linked to the delivery of vast quantities of terrigenous sediments from New Guinea. The composition and distribution, and sedimentological and geochemical properties, of seabed and suspended sediments in north and central Torres Strait have been determined to investigate this issue. In northern Torres Strait, next to Saibai Island, seabed sediments comprise poorly sorted, muddy, mixed calcareous-siliciclastic sand. Seabed sediments in this region are dominated by aluminosilicate (terrigenous) phases. In central Torres Strait, next to Turnagain Island, seabed and suspended sediments comprise moderately sorted coarse to medium carbonate sand. Seabed sediments in this region are dominated by carbonate and magnesium (marine) phases. Mean Cu/Al ratios for seabed sediments next to Saibai Island are 0.01, and are similar to those found in New Guinea south coastal sediments by previous workers. Mean Cu/Al ratios for seabed sediments next to Turnagain Island are 0.02, indicating an enrichment of Cu in central Torres Strait. This enrichment comes from an exogenous biogenic source, principally from foraminifers and molluscs. We could not uniquely trace terrigenous sediments from New Guinea to Turnagain Island in central Torres Strait. If sediments are a factor in the widespread seagrass dieback in central Torres Strait, then our data suggest these are marine-derived sediments sourced from resuspension and advection from the immediate shelf areas and not terrigenous sediments dispersed from New Guinea rivers. This finding is consistent with outputs from recently developed regional hydrodynamic and sediment transport models.

  • These images are derived from the "Gravity Anomaly Grid of the Australian Region" (GEOCAT record: 67240). That grid combines accurate onshore gravity measurements, with satellite data over the offshore region. The cell values represent simple Bouguer anomalies at a density of 2.67 tonnes per cubic metre onshore and free-air anomalies offshore. The grid cell size is 0.5 minutes of arc, which is equivalent to about 800 metres.