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  • This gravity anomaly grid is derived from observations stored in the Australian National Gravity Database (ANGD) as at February 2016 as well as data from the 2013 New South Wales Riverina gravity survey. Out of the approximately 1.8 million gravity observations 1,371,998 gravity stations in the ANGD together with 19,558 stations from the Riverina survey were used to generate this grid. The grid shows complete Bouguer anomalies over onshore continental Australia. The data used in this grid has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. Terrain corrections to gravity were calculated using both offshore bathymetry and onshore topography data. These terrain corrections were applied to the spherical cap Bouguer anomalies used in the Bouguer Gravity Anomaly Grid of Onshore Australia 2016 to produce the complete Bouguer anomaly values shown in this grid.

  • This gravity anomaly grid is derived from observations stored in the Australian National Gravity Database (ANGD) as at February 2016 as well as data from the 2013 New South Wales Riverina gravity survey. Out of the almost 1.8 million records in the ANGD approximately 1.4 million stations together with 19,558 stations from the Riverina survey were used to generate this grid. This product shows spherical cap Bouguer anomalies over onshore continental Australia. The data used in this grid has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. The spherical cap Bouguer anomalies in this grid are the combination of Bullard A and B corrections to the Free Air anomaly values using a density of 2670 kg/m^3.

  • Total magnetic intensity (TMI) data measures variations in the intensity of the Earth magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. A variable reduction to Pole is aimed at locating magnetic anomalies exactly above their source bodies and without any distortion. The 2019 Total magnetic Intensity (TMI) grid of Australia with variable reduction to pole (VRTP) has a grid cell size of ~3 seconds of arc (approximately 80 m). This grid only includes airborne-derived TMI data for onshore and near-offshore continental areas. The VRTP processing followed a differential reduction to pole calculation up to 5th order polynomial. Magnetic inclination and declination were derived from the IGRF-11 geomagnetic reference model using a data representative date of January 2005 and elevation 300 m.

  • The filtered terrestrial dose rate grid is a derivative of the 2019 radiometric or gamma-ray grid of Australia, made of a combination of over 600 individual survey grids. The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data are collected on airborne geophysical surveys conducted by Commonwealth, State and Northern Territory Governments and the private sector. The terrestrial dose rate grid is derived as a linear combination of the filtered K, U and Th grids. A low pass filter is applied to the unfiltered grid to generate the filtered terrestrial dose rate grid. The grid cell size is about 100m (0.001 degrees).

  • The uranium over potassium grid is a derivative of the 2019 radiometric or gamma-ray grid of Australia comprising over 600 airborne gamma-ray spectrometric surveys. The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data are collected on airborne geophysical surveys conducted by Commonwealth, State and Northern Territory Governments and the private sector. The 2019 uranium over potassium grid has a cell size of about 100 m (0.001 degrees) and is derived from the filtered uranium and potassium grids.

  • This grid is derived from gravity observations stored in the Australian National Gravity Database (ANGD) as at February 2016 as well as data from the 2013 New South Wales Riverina gravity survey. Out of the approximately 1.8 million gravity observations 1,371,998 gravity stations in the ANGD together with 19,558 stations from the Riverina survey were used to generate this image. The grid shows isostatic residual gravity anomalies over onshore continental Australia. The data used in this grid has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. The isostatic corrections were based on the assumption that topographic loads are compensated at depth by crustal roots following the Airy-Heiskanen isostatic principle. A crustal density of 2670 kg/m3 was used for the isostatic correction, with an assumed density contrast between the crust and mantle of 400 kg/m3. An initial average depth to Moho at sea level of 37 km was used in the calculation. The isostatic corrections were then applied to the Complete Bouguer Gravity Anomaly Grid of Onshore Australia 2016 to produce the Isostatic Residual Gravity Anomaly Grid of Onshore Australia 2016.

  • The unfiltered thorium grid is a derivative of the 2019 radiometric or gamma-ray grid of Australia which is a merge of over 600 individual gamma-ray spectrometric surveys. The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data are collected on airborne geophysical surveys conducted by Commonwealth, State and Northern Territory Governments and the private sector. The 2019 unfiltered thorium grid has a cell size of about 100 m (0.001 degrees) and shows thorium element concentrations of the Australia region.

  • The unfiltered uranium grid is a derivative of the 2019 radiometric or gamma-ray grid of Australia which is a merge of over 600 individual gamma-ray spectrometric surveys. The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium, uranium and thorium. The data are collected on airborne geophysical surveys conducted by Commonwealth, State and Northern Territory Governments and the private sector. The 2019 unfiltered uranium grid has a cell size of about 100m (0.001 degrees) and shows uranium element concentrations of the Australia region.

  • The unfiltered potassium grid is a derivative of the 2019 radiometric grid of Australia. The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data are collected on airborne geophysical surveys conducted by Commonwealth, State and Northern Territory Governments and the private sector. The 2019 unfiltered potassium grid has a cell size of about 100 m (0.001 degrees) and shows potassium element concentrations of the Australia region. Potassium is the seventh most abundant element in the Earth's crust. The potassium concentration grid can be used to locate minerals and compounds containing potassium.

  • Total magnetic intensity (TMI) data measures variations in the intensity of the Earth magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. The first vertical derivative (1VD) grid is derived from the 2019 Total magnetic Intensity (TMI) grid of Australia which has a grid cell size of ~3 seconds of arc (approximately 80 m). As the vertical derivative filter is essentially a high-pass filter, longer wavelengths are suppressed, and shorter wavelengths emphasized. The magnetic units of the data are in nT per metre.