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    Total magnetic intensity (TMI) data measures variations in the intensity of the Earth's 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 data 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 Magnetic Anomaly Map of Australia, Seventh Edition, 2019 TMI Greyscale image is a greyscale image of the TMI grid of the Magnetic Anomaly Map of Australia, Seventh Edition, 2019. The 2019 Total magnetic Intensity (TMI) grid of Australia 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. Since the sixth edition was released in 2015, data from 234 new surveys have been added to the database, acquired mainly by the State and Territory Geological Surveys. The new grid was derived from a re-levelling of the national magnetic grid database. The survey grids were levelled to each other, and to the Australia Wide Airborne Geophysical Survey (AWAGS), which serves as a baseline to constrain long wavelengths in the final grid. It is estimated that 33 500 000 line-kilometres of survey data were acquired to produce the 2019 grid data, about 2 000 000 line-kilometres more than for the previous edition. The grid used to produce this greyscale image has a cell size of 0.00083 degrees (approximately 80m). This greyscale image shows the magnetic response of subsurface features with contrasting magnetic susceptibilities. The image can also be used to locate structural features such as dykes.

  • 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 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 radiometric thorium grid has a cell size of 0.004 degrees (approximately 430m) and shows thorium element concentration of the Canning Basin (Gordon Downs, Billiluna, Lucas, Stansmore), WA, 1980 survey. The data used to produce this grid was acquired in 1980 by the WA Government, and consisted of 57126 line-kilometres of data at 1500m line spacing and 150m terrain clearance.

  • 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 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 radiometric thorium grid has a cell size of 0.001 degrees (approximately 110m) and shows thorium element concentration of the Georgina, NT, 2002 survey. The data used to produce this grid was acquired in 2002 by the NT Government, and consisted of 91100 line-kilometres of data at 400m line spacing and 80m terrain clearance.

  • 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 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 radiometric potassium grid has a cell size of 0.000833 degrees (approximately 90m) and shows potassium element concentration of the Yowalga Sub-Basin, WA, 1995-1996 survey. The data used to produce this grid was acquired in 1996 by the WA Government, and consisted of 87431 line-kilometres of data at 500m line spacing and 80m terrain clearance.

  • 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 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 radiometric potassium grid has a cell size of 0.001 degrees (approximately 100m) and shows potassium element concentration of the SA Exploration Initiative 1994 - Area B9 survey. The data used to produce this grid was acquired in 1994 by the SA Government, and consisted of 29442 line-kilometres of data at 400m line spacing and 85m terrain clearance.

  • 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 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 radiometric potassium grid has a cell size of 0.004 degrees (approximately 430m) and shows potassium element concentration of the Canning Basin (Charnley, Lennard R, Noonkanbah, Crossland), WA, 1989 survey. The data used to produce this grid was acquired in 1989 by the WA Government, and consisted of 51022 line-kilometres of data at 1500m line spacing and 150m terrain clearance.

  • 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.

  • 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 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 radiometric uranium grid has a cell size of 0.000833 degrees (approximately 90m) and shows uranium element concentration of the Balladonia - Zanthus, WA, 2008 survey. The data used to produce this grid was acquired in 2009 by the WA Government, and consisted of 43948 line-kilometres of data at 400m line spacing and 60m terrain clearance.

  • The unfiltered terrestrial dose rate 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 unfiltered terrestrial dose rate grid is derived as a linear combination of the unfiltered K, U and Th grids, and has a cell size of about 100m (0.001 degrees).

  • 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 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 radiometric potassium grid has a cell size of 0.000833 degrees (approximately 90m) and shows potassium element concentration of the Normanton, Qld, 2008 survey. The data used to produce this grid was acquired in 2008 by the Qld Government, and consisted of 114487 line-kilometres of data at 400m line spacing and 80m terrain clearance.