2020
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This web service provides access to groundwater raster products for the Upper Burdekin region, including: inferred relative groundwater recharge potential derived from weightings assigned to qualitative estimates of relative permeability based on mapped soil type and surface geology; Normalised Difference Vegetation Index (NDVI) used to map vegetation with potential access to groundwater in the basalt provinces, and; base surfaces of basalt inferred from sparse available data.
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Gold deposits form in a range of geodynamic settings and styles of deposition, associated with specific characteristics in fluid source and chemistry. These differences may lead to differences in the minerals that are deposited in the ascent pathway, and thus alter the physical properties that can be measured at different levels in the lithosphere. Models derived from magnetotelluric data are sensitive to lithospheric resistivity variations and have been increasingly applied to mineral exploration, with evidence emerging for a spatial association between many mineral deposits and lower crustal conductors. Southeastern Australia has estimated resource of ~5000 t gold contained within a variety of deposit styles. A resistivity model of this region was recently published from Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) data under a collaborative project between Geoscience Australia, the Geological Survey of New South Wales, and the Geological Survey of Victoria. This showed a strong spatial correlation between lower crustal conductors and gold deposits. In this presentation we examine the statistical and geological significance of this correlation for different deposit styles. We demonstrate that there are clear differences in the resistivity expression between different styles of gold deposition. The variability may reflect differences in the fluid source chemistry and geodynamic setting of the deposits, and will have important implications for the exploration of these resources.
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Mineral deposits are the products of lithospheric-scale processes. Imaging the structure and composition of the lithosphere is therefore essential to better understand these systems, and to efficiently target mineral exploration. Seismic techniques have unique sensitivity to velocity variations in the lithosphere and mantle, and are therefore the primary means available for imaging these structures. Here, we present the first stage of Geoscience Australia's passive seismic imaging project (AusArray), developed in the Exploring for the Future program. This includes generation of compressional (P) and shear (S) body-wave tomographic imaging models. Our results, on a continental scale, are broadly consistent with a priori expectations for regional lithospheric structure and the results of previously published studies. However, we also demonstrate the ability to resolve detailed features of the Australian lithospheric mantle underneath the dense seismic deployments of AusArray. Contrasting P- and S-wave velocity trends within the Tennant Creek – Mount Isa region suggest that the lithospheric root may have undergone melt-related alteration. This complements other studies, which point towards high prospectivity for iron oxide–copper–gold mineralisation in the region. <b>Citation: </b>Haynes, M.W., Gorbatov, A., Hejrani, B., Hassan, R., Zhao, J., Zhang, F. and Reading, A.M., 2020. AusArray: imaging the lithospheric mantle using body-wave tomography. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.
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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 thorium grid has a cell size of 0.00018 degrees (approximately 20m) and shows thorium element concentration of the NTGS Tanami NS 4NE Region Detailed Airborne Magnetic Radiometric and Digital Elevation Survey, NT, 2018 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2018 by the NT Government, and consisted of 10063 line-kilometres of data at 100m 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.
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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 thorium grid has a cell size of 0.00018 degrees (approximately 20m) and shows thorium element concentration of the NTGS Tanami EW 5N Region Detailed Airborne Magnetic Radiometric and Digital Elevation Survey, NT, 2018 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2018 by the NT Government, and consisted of 11735 line-kilometres of data at 100m 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.
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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 thorium grid has a cell size of 0.00018 degrees (approximately 20m) and shows thorium element concentration of the NTGS Tanami NS 4NW Region Detailed Airborne Magnetic Radiometric and Digital Elevation Survey, NT, 2018 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2018 by the NT Government, and consisted of 16194 line-kilometres of data at 100m 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.
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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 GSWA Kauring Merged TMI Grid Geodetic has a cell size of 0.0002 degrees (approximately 21m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 2011 by the WA Government, and consisted of 229959 line-kilometres of data at 200m line spacing and 50m 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. This radiometric thorium grid has a cell size of 0.0002 degrees (approximately 21m) and shows thorium element concentration of the Kauring (Moora, Corrigin) merge, 2011-2012 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2011 by the WA Government, and consisted of 229959 line-kilometres of data at 200m line spacing and 50m 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. This radiometric uranium grid has a cell size of 0.0002 degrees (approximately 21m) and shows uranium element concentration of the Kauring (Moora, Corrigin) merge, 2011-2012 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2011 by the WA Government, and consisted of 229959 line-kilometres of data at 200m line spacing and 50m 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 GSWA Eucla Basin 2 Loongana Doserate Grid Geodetic has a cell size of 0.00042 degrees (approximately 43m) and shows the terrestrial dose rate of the Loongana, WA, 2010 (Eucla Basin 2). The data used to produce this grid was acquired in 2010 by the WA Government, and consisted of 114979 line-kilometres of data at 200m line spacing and 50m terrain clearance.