SA
Type of resources
Keywords
Publication year
Scale
Topics
-
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. 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 this grid to generate the filtered terrestrial dose rate grid. This GSSA Coompana Doserate Grid Geodetic has a cell size of 0.00083 degrees (approximately 86m) and shows the terrestrial dose rate of the Coompana, SA, 2015. The data used to produce this grid was acquired in 2015 by the SA Government, and consisted of 286817 line-kilometres of data at a line spacing between 200m and 400m, and 80m terrain clearance.
-
The major gravity anomalies in central and western Australia occur as elongate dipoles, either in isolation or in a series. Each dipole is thought to be caused by an abrupt change in mean crustal density at the junction of two crustal blocks and by the associated isostatically compensating masses. Typically one block has along its margin a strip with anomalously high mean crustal density, and the other block has normal density crust covered by several kilometres of low density sediment. The observed anomalies are consistent with the anomalous masses being isostatically compensated by variations in the thickness of the crust, the crustal thickness variations being gradual and extending to about 100 km from the boundaries of the anomalous bodies. The crustal block boundaries inferred from dipole anomalies correspond in position with the crustal block boundaries inferred from geology, and approximately with the position of block boundaries inferred from changes in the gravity trend pattern. Usually the block with younger basement has high density material along its margin, and the other, older block is covered with sediment; both these features are likely to be caused by the process that created or emplaced the younger block. The presence of relatively dense material high in the crust along the margins of the younger blocks suggests that younger blocks are not superficial features on a uniform old crust. The dipole anomalies on the Australian Precambrian crust are similar in magnitude and tectonic position to those recognised at Precambrian province boundaries in Canada.
-
The South Australian seismic network comprises 12 short-period, permanent stations distributed over a large area of the State. The network provides earthquake monitoring down to magnitude ML ~ 2 for most of the State, with an improved location capability of ML ~ 1 for the seismically active Adelaide Geosyncline zone. At any time the permanent network can be augmented by 13 sets of portable equipment, which include 6 microprocessor controlled, battery-powered digital event recorders built in-house. The earthquake data are analysed on a dedicated Data General computer system and graphics unit. The software is an integrated, interactive system of seismic analysis routines, covering all the data processing needs of the network, from station calibrations and updating of station data, through the determination of locations and magnitudes of local earthquakes and the needs of microearthquake survey data processing, to the retrieval and display of earthquake statistics from an archived data base. The computerised seismic data processing system has been used in the routine analysis of all local earthquakes and microearthquake surveys in South Australia since the beginning of 1978.
-
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. The Geological Survey of South Australia commissioned the Gawler Craton Airborne Survey (GCAS) as part of the PACE Copper initiative. The airborne geophysical survey was flown over parts of the Gawler Craton in South Australia. The program was designed to capture new baseline geoscientific data to provide further information on the geological context and setting of the area for mineral systems (http://energymining.sa.gov.au/minerals/geoscience/pace_copper/gawler_craton_airborne_survey). This radiometric thorium grid has a cell size of 0.0004 degrees (approximately 41m) and shows thorium element concentration of the Kingoonya Airborne Magnetic Radiometric and DEM survey, SA, 2018 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2018 by the SA Government, and consisted of 149477 line-kilometres of data at 200m line spacing and 60m terrain clearance. To constrain long wavelengths in the grid, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey grid.
-
The Digital Elevation Model represents ground surface topography between points of known elevation. The elevation data was calculated using the altimeters and Global Positioning System (GPS) sensor used for the benefit of airborne magnetic and radiometric data on the same survey. The elevation is the height relative to the Australian Height Datum GDA94 (AUSGEOID09). The processed elevation data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. These line dataset from the Kingoonya Airborne Magnetic Radiometric and DEM survey, SA, 2018 survey were acquired in 2018 by the SA Government, and consisted of 149477 line-kilometres of data at 200m line spacing and 60m 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 Gawler Craton Airborne Survey, Tranche 2, Block 8b, Billa Kalina, 2017 (P1300), radiometric line data were acquired in 2017 by the SA Government, and consisted of 90584 line-kilometres of data at 200m line spacing and 60m 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 0.0004 degrees (approximately 41m) and shows potassium element concentration of the Kingoonya Airborne Magnetic Radiometric and DEM survey, SA, 2018 in units of percent (or %). The data used to produce this grid was acquired in 2018 by the SA Government, and consisted of 149477 line-kilometres of data at 200m line spacing and 60m terrain clearance. To constrain long wavelengths in the grid, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey grid.
-
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 0.0004 degrees (approximately 41m) and shows thorium element concentration of the Andamooka Airborne Magnetic Radiometric and DEM Survey, 2017 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2017 by the SA Government, and consisted of 81874 line-kilometres of data at 200m line spacing and 60m terrain clearance.
-
Several petrographically and geochemically distinct suites of mafic dykes crop out in the Mesoproterozoic Musgrave Block. Intergranular dolerites (group A), as well as the voluminous Giles Complex layered mafic-ultramafic intrusions and Tollu Group basaltic volcanics, were formed by large-scale melting of heterogeneous enriched subcontinental lithospheric mantle about 1080 Ma ago, more than 100 m.y. after the 1200-Ma regional high-grade metamorphism of the Musgrave Block country rocks. The coeval Kulgera (eastern Musgrave Block) and Stuart (Arunta Block) dyke swarms are chemically and isotopically similar. Slightly younger (-1000 Ma), particularly heterogeneous olivine dolerites (group C) were also derived from a similarly enriched source. Mantle heterogeneity was apparently both lateral (as group C dolerites show significant geographical variations) and vertical (because chemically distinct dyke suites of similar age crop out in the same area). Microgabbro dykes and sills associated with troctolitic intrusions of the Giles Complex are compositionally similar to both gabbronorite intrusions of the Giles Complex and to group A dolerite dykes therein. The least fractionated microgabbros are probably representative of an evolved magma that was parental to the major gabbroic intrusions of the Giles Complex, and underwent some degree of high-pressure pyroxene ± olivine fractionation. They cannot be directly parental to the leucotroctolite cumulates. which reflect much more extensive high-pressure fractionation before they were emplaced. Quartz dolerites emplaced 800 Ma ago (group B) were derived by higher-pressure partial melting of a much less enriched (-Nd +2.8 to +3.8), homogeneous asthenospheric mantle source, probably related to mantle-plume activity. They are virtually identical chemically and isotopically with dykes, including the Amata (eastern Musgrave Block) and Gairdner (Gawler Craton) dyke swarms, that crop out over a distance of more than 1000 km.
-
Digital Elevation data record the terrain height variations from the processed point- or line-located data recorded during a geophysical survey. This GSSA Barton Elevation laser grid geodetic is elevation data for the Barton Airborne Magnetic Radiometric and DEM Survey, SA, 2017. This survey was acquired under the project No. 1284 for the geological survey of SA. The grid has a cell size of 0.00042 degrees (approximately 43m). This grid contains the ground elevation relative to the geoid for the Barton Airborne Magnetic Radiometric and DEM Survey, SA, 2017. It represents the vertical distance from a location on the Earth's surface to the geoid. The data are given in units of meters. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.