SA
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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 SA Semi-Detailed Gravity Survey, 2000A3 (P200056) contains a total of 85 point data values acquired at a spacing of 2000 metres. The data is located in SA and were acquired in 2000, under project No. 200056 for None.
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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 Semi-Detailed Gravity Traverses, SA 2000A4 (P200057) contains a total of 13 point data values acquired at a spacing between 1200 and 8000 metres. The data is located in SA and were acquired in 2000, under project No. 200057 for None.
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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 Black Hill Gravity SA 00A1 (P200071) contains a total of 259 point data values acquired at a spacing between 200 and 400 metres. The data is located in SA and were acquired in 2000, under project No. 200071 for None.
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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 Eucla Gawler Deep Crustal Seismic Gravity Survey (P201363) contains a total of 2086 point data values acquired at a spacing of 400 metres. The data is located in SA, WA and were acquired in 2013, under project No. 201363 for Geoscience Australia.
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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. These line dataset from the Marree-Warrina Airborne Magnetic & Radiometric Survey, SA, 2012 survey were acquired in 2012 by the SA Government, and consisted of 132484 line-kilometres of data at 400m line spacing and 80m terrain clearance. To constrain long wavelengths in the data, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey data. This survey data is essentially levelled to AWAGS.
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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 Warrina, SA, 2012 (P1255), radiometric line data, AWAGS levelled were acquired in 2012 by the SA Government, and consisted of 132484 line-kilometres of data at 400m line spacing and 80m terrain clearance. To constrain long wavelengths in the data, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey data. This survey data is essentially levelled to AWAGS.
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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 0.00083 degrees (approximately 86m) and shows uranium element concentration of the Coompana, SA, 2015 in units of parts per million (or ppm). 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.
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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 Marree Dose Grid Geodetic has a cell size of 0.00083 degrees (approximately 87m) and shows the terrestrial dose rate of the Marree-Warrina Airborne Magnetic & Radiometric Survey, SA, 2012. The data used to produce this grid was acquired in 2012 by the SA Government, and consisted of 132484 line-kilometres of data at 400m line spacing and 80m terrain clearance.
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The Brunhes/Matuyama (B/M) polarity transition (0.78 Ma) marks the end of the last major period of reversed polarity of the Earth s magnetic field. Weathered regolith materials with reversed polarity chemical remanent magnetisation (CRM) must, therefore, predate the B/M transition. Reversed polarity magnetisation can be preserved in a wide variety of regolith materials in eastern Australia, particularly in oxidising environments. At Sellicks Beach and Hallett Cove near Adelaide, the B/M transition is identified in a strongly mottled unit, the Ochre Cove Formation. In Canberra, strongly weathered fan gravels on the east side of Black Mountain have a mixture of reversed and normal polarities, indicating initial weathering and deposition before 0.78 Ma and continued weathering since then. In north Queensland, a soil formed on a 2.46 Ma basalt flow has reversed polarity in the lower B horizon, indicating that, over the last 0.78 Ma, pedogenesis has had little or no effect on the secondary iron minerals carrying the magnetic remanence in that part of the profile.
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The Acraman ejecta horizon is a thin (0-40 cm ) sand/breccia unit consisting almost entirely of angular volcanic fragments. The horizon occurs within Neoproterozoic (~590 Ma) deep-water (below storm-wave-base) shales of the Adelaide Geosyncline (Bunyeroo Formation) and Officer Basin (Rodda beds). Much evidence points to the derivation of the horizon from Australias largest meteorite impact feature, the Acraman structure, in the Gawler Ranges. The ejecta horizon contains anomalous quantities of Ir, Au, Pt, Pd, Ru, and Cr, consistent with a meteoritic source for the horizon. Other evidence for an impact-related origin is the presence of shattered mineral grains, multiple sets of planar shock lamellae within quartz phenocrysts, the occurrence of small shatter cones on clasts, and the presence of altered melt particles. Two major sedimentological styles of ejecta occur in the Adelaide Geosyncline: type 1 ejecta sequences are characterised by a distinctive lonestone/breccia-sandy mudstone-graded-sandstone sequence whose clasts are almost perfectly sorted and normally graded; and type 2 sequences are characterised by weak normal grading, poor sorting, and common cross-lamination. Type 1 ejecta sequences are widespread in the central and eastern portions of the Adelaide Geosyncline, while type 2 sequences are more common in the western part of the Geosyncline. In the Officer Basin, the ejecta horizon consists of thin (0-0.7 cm) layers of sand-size angular volcanic clasts. We interpret type 1 sequences as primary fallout deposits whose perfect sorting and normal grading reflects suspension settling; and type 2 sequences as ejecta that have been completely reworked by impact-induced tsunamis. When treated as a single sediment sample, the grain size distribution in the type 1 ejecta sequences displays two quite distinct populations: the basal breccia forms a very poorly sorted population; and the graded sand constitutes a moderately well sorted population. These two grainsize populations might represent different transport modes: the breccia by fireball processes or ejecta flows, and the sand by atmospheric processes such as impact-induced air-blasts.