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  • Total magnetic intensity data measures variations in the intensity of the Earths magnetic field caused by the contrasting content of rock-forming minerals in the Earths crust. The data are collected on airborne geophysical surveys conducted by Commonwealth, State & NT Governments and the private sector.

  • Digital Elevation Model data record the terrain height variations from the processed point-located data recorded on an airborne geophysical survey. The aircraft altimeter data records the height of the aircraft above the ground and the aircraft GPS records the height of the aircraft above the ellipsoid. Subtracting the two values enables the height of the terrain beneath the aircraft relative to the ellipsoid to be calculated. This ellipsoidal terrain height is corrected for the variation between the ellipsoid and the geoid (the n-value correction) to produce terrain heights relative to sea level.

  • Although the Bureau of Mineral Resources, Geology and Geophysics was created in 1946, it did not compile an annual report until 1971. The series continued under this title up to 1976, all but the last providing summaries of annual activities by broad sections (functions and organisation, field operations, laboratory studies, observatories, and so on). The 1976 Annual Report adopted a shorter format, a general outline of the role, objectives and programs of the Bureau being followed by a selection of short articles on the "more innovative and conclusive activities" of that year. This new format was retained in 1977 when a title change was made and the annual summaries became known as BMR Yearbooks.

  • A predictive model of weathering intensity or the degree of weathering has been generate over the Australian continent. The model has been generated using the Random Forest decision tree machine learning algorithm. The algorithm is used to establish predictive relationships between field estimates of the degree of weathering and a comprehensive suite of covariate or predictive datasets. The covariates used to generate the model include satellite imagery, terrain attributes, airborne radiometric imagery and mapped geology. The weathering intensity model is an estimate of the degree of surface weathering only. The interpretation of the weathering intensity is different for in-situ or residual landscapes compared with transported materials within depositional landscapes. In residual landscapes, weathering process are operating locally whereas in depositional landscapes the model is reflecting the degree of weathering either prior to erosion and subsequent deposition, or weathering of sediments after being deposited. The degree of surface weathering is particularly important in Australia where variations in weathering intensity correspond to the nature and distribution of regolith (weathered bedrock and sediments) which mantles approximately 90% of the Australian continent. The weathering intensity prediction has been generated using the Random Forest decision tree machine learning algorithm. The algorithm is used to establish predictive relationships between field estimates of the degree of weathering and a comprehensive suite of covariate or predictive datasets. The covariates used to generate the model include satellite imagery, terrain attributes, airborne radiometric imagery and mapped geology. Correlations between the training dataset and the covariates were explored through the generation of 300 random tree models. An r-squared correlation of 0.85 is reported using 5 K-fold cross-validation. The mean of the 300 models is used for predicting the weathering intensity and the uncertainty in the weathering intensity is estimated at each location via the standard deviation in the 300 model values. The predictive weathering intensity model is an estimate of the degree of surface weathering only. The interpretation of the weathering intensity is different for in-situ or residual landscapes compared with transported materials within depositional landscapes. In residual landscapes, weathering process are operating locally whereas in depositional landscapes the model is reflecting the degree of weathering either prior to erosion and subsequent deposition, or weathering of sediments after being deposited. The weathering intensity model has broad utility in assisting mineral exploration in variably weathered geochemical landscapes across the Australian continent, mapping chemical and physical attributes of soils in agricultural landscapes and in understanding the nature and distribution of weathering processes occurring within the upper regolith. <b>Value: </b>Weathering intensity is an important characteristic of the earth’s surface that has a significant influence on the chemical and physical properties of surface materials. Weathering intensity largely controls the degree to which primary minerals are altered to secondary components including clay minerals and oxides. In this context the weathering intensity model has broad application in understanding geomorphological and weathering processes, mapping soil/regolith and geology. <b>Scope: </b>National dataset which over time can be improved with additional sites for training and thematic datasets for prediction. <b>To view catalogue records associated with this collection click on the keyword HVC_144633 below</b>

  • Geoscience Australia is responsible for the records and custody of Commonwealth aerial photography, acquired since 1928 up to the most recent analogue film capture in mid-1990s. Subsequent comparable information is available in the form of satellite imagery or direct digital aerial image capture. The majority of the landmass of Australia is covered by black and white photography at 1:80,000 scale. The near complete coverage was undertaken three times, in 1950s, 1960s and 1980s. Metadata about aerial photo surveys is recorded as flight diagrams on 1:250,000, 1:100,000 & 1:50,000 maps showing the approximate aircraft flight paths, selective depiction of photo centres, and other survey parameters. <b>Value:</b> Aerial imagery can be used to study change over time for land use, vegetation, environmental quality, etc. <b>Scope: </b>Images in the collection have been acquired since 1928 up to the most recent analogue film capture in mid-1990s. Subsequent comparable information is available in the form of satellite imagery or direct digital aerial image capture. The majority of the landmass of Australia is covered by black and white photography at 1:80,000 scale. The near complete coverage was undertaken three times, in 1950s, 1960s and 1980s. <b>To view the entire collection click on the keyword "HVC_144649" in the below Keyword listing</b>

  • This data collection is comprised of radiometric (gamma-ray spectrometric) surveys acquired across Australia by Commonwealth, State and Northern Territory governments and the private sector with project management and quality control undertaken by Geoscience Australia. The radiometric method measures naturally occurring radioactivity arising from gamma-rays. In particular, the method is able to identify the presence of the radioactive isotopes potassium (K), uranium (U) and thorium (Th). The measured radioactivity is then converted into concentrations of the radioelements K, U and Th in the ground. Radiometric surveys have a limited ability to see into the subsurface with the measured radioactivity originating from top few centimetres of the ground. These surveys are primarily used as a geological mapping tool as changes in rock and soil type are often accompanied by changes in the concentrations of the radioactive isotopes of K, U and Th. The method is also capable of directly detecting mineral deposits. For example, K alteration can be detected using the radiometric method and is often associated with hydrothermal ore deposits. Similarly, the method is also used for U and Th exploration, heat flow studies, and environmental mapping purposes such as characterising surface drainage features. The instrument used in radiometric surveys is a gamma-ray spectrometer. This instrument measures the number of radioactive emissions (measured in counts per second) and their energies (measured in electron volts (eV)). Radiometric data are simultaneously acquired with magnetic data during airborne surveys and are a non-invasive method for investigating near-surface geology and regolith. <b>To view catalogue records associated with this collection click on the keyword HVC_144636 below.</b>

  • This data collection are comprised of magnetic surveys acquired across Australia by Commonwealth, State and Northern Territory governments and the private sector with project management and quality control undertaken by Geoscience Australia. Magnetic surveying is a geophysical method for measuring the intensity (or strength) of the Earth’s magnetic field, which includes the fields associated with the Earth’s core and the magnetism of rocks in the Earth’s crust. Measuring the magnetism of rocks, in particular, provides a means for the direct detection of several different types of mineral deposits and for geological mapping. The magnetism of rocks depends on the volume, orientation and distribution of their constituent magnetic minerals (namely magnetite, monoclinic pyrrhotite, maghaemite and ilmenite). The instrument used in magnetic surveys is a magnetometer, which can measure the intensity of the magnetic field in nanoteslas (nT). Magnetic surveys in this collection have been acquired using aircraft or ship-mounted magnetometers and are a non-invasive method for investigating subsurface geology. <b>To view catalogue records associated with this collection click on the keyword HVC_144635 below.</b>

  • This collection of documents detail various field techniques and processes that GA conduct. They are in conjunction with a series of Field Activity Technique Engagement Animations. The target audience are the communities that are impacted by our data acquisition activities. Field techniques in this collection include; • AEM fixed wing • AEM Helicopter • Borehole Geophysics • Goundwater sampling • Magnetotelluric (MT) surveys • Passive seismic surveys • Rapid Deployment Kits (RDKs) • Reflection seismic surveys • Surface Magnetic Resonance (SMR) surveys • Stratigraphic drilling

  • Survey Data captured after severe natural hazard events covering a range of hazards with specific attributes. This observational information is used as input data to assessing vulnerability to natural hazard, but is not made available in its raw form. <b>Value: </b>Used to assess impacts from natural disasters and thereby reduce future risks. <b>Scope: </b>Australia, data from Papua New Guinea, Indonesian province of West Sumatra (Padang) and New Zealand

  • Descriptions of and measurements from field sites and samples from geological (including regolith) surveys. <b>Value: </b>Used to constrained surface geology, important in resource exploration and understanding physical environment. <b>Scope: </b>Mapping surveys mainly in Australia, but also in Antarctica, Oceania and south-east Asia. <b>To view the entire collection click on the keyword "HVC_144684" in the below Keyword listing</b>