The Ord is one of the largest rivers in northern Australia and is located in the Kimberley region of Western Australia. In this study we show that the lower Ord landscape near Kununurra in Western Australia consists of a large scale ancient landscape, possibly pre-Cambrian, being exhumed from beneath flat-lying Cambrian to Carboniferous cover rocks. Additional post-Permian landscapes are being formed by this process. The Ord Valley alluvium is of late Pleistocene to Holocene in age and consts off upward fining gravels, sands and clays infilling an inset valley profile. The Ord River initially flowed to the sea via the keep River estuary, however a major avulsion, possibly due to sedimentatain topping a low point in the surrounding valley walls, occurred possibly as recently as 1,800 years ago. As a result to mouth of the Ord shifted some 100 km to the east, to Cambridge Gulf, its course through the former alluvial plain and along the new course across the coastal plain was incised, and a scabland formed across the low point of Tararar Bar. This association of very ancient (pre-Paleozoic) landscape elements and by thin, very young weathering profiles and young sedimentary accumulations in alluvial valleys is paradoxical in the broader Australian pattern where very ancient landscape elements are associated with ancient sedimentary infill and weathering profiles.

Airborne electromagnetic (AEM) data are being acquired by Geoscience Australia (GA) under the Australian Government's Onshore Energy Security Program (OESP) in areas considered to have potential for uranium or thorium mineralisation. In contrast to deposit-scale investigations carried out by industry these surveys are designed to reveal new geological information at a regional scale. The Frome AEM survey shown in Figure 1 was flown by Fugro Airborne Surveys for GA, using the TEMPESTTM time-domain system. The survey was conducted with the aims of reducing exploration risk, stimulating exploration investment and enhancing prospectivity within the region primarily for uranium, but also for other commodities including copper, gold, silver, lead, zinc, iron ore and potable groundwater. The Frome AEM survey was primarily designed to be a regional mapping program for mapping surface and subsurface geological features that may be associated with sandstone-hosted uranium systems. The data are also capable of being interpreted for landscape evolution studies within the flanks of the tectonically active Curnamona Province and Flinders Ranges of South Australia. In this article we present an enhanced set of conductivity estimates which are now available from the GA website free of charge. These conductivity estimates reveal new geological information

Provides an overview of the Project in the context of the Onshore Energy Security Program in advance of the presentations dealing with the acquisition, data, procedures and interpretation results of the survey.

Between the 31st of March 2013 and the 15th of May 2013, Fugro Airborne Surveys Pty. Ltd., (FAS, now known as CGG Aviation (Australia) Pty Ltd) undertook a TEMPEST® airborne electromagnetic and magnetic survey over the South West Coastal Plain and the South Coast areas of Western Australia. There were four separate project areas: (1) Swan Coastal Plain, (2) Scott Coastal Plain, (3) Albany, (4) Esperance. The survey is designed to map groundwater resources and assess aquifer sustainability in four separate areas of southern WA. The survey areas are located in: 1. Esperance: Traverses spaced 300 & 600 metres apart in a north-south direction at 120 metres above ground level totalling 1,133 line km. 2. Albany: Traverses spaced 300 & 600 metres apart in a north-south direction at 120 metres above ground level totalling 2,163 line km. 3. Scott Coastal Plain: Traverses spaced 600 metres apart in a ne-sw direction at 120 metres above ground level totalling 2,980 line km. 4. Swan Coastal Plain: Traverses spaced 600 metres apart in a nw-se direction at 120 metres above ground level totalling 2,303 line km. The total coverage of the survey amounted to 8,579 line kilometres. The survey was flown using a Shorts Skyvan (SC3-200) aircraft, registration VH-WGT, owned and operated by FAS. The survey was commissioned by the Western Australia Department of Water, and was managed by Geoscience Australia. The Survey received funding from the WA Government's Royalties for Regions program to assess, plan and investigate regional water availability in Western Australia. The data release includes the final contractor supplied datasets. The data are available from Geoscience Australia's web site free of charge. Each data package includes: 1. Point-located electromagnetic data with associated position, altimeter, orientation, magnetic, and derived ground elevation data. These data are in ASCII column format with associated ASEG-GDF2 header files. 2. Point-located conductivity estimates derived using the EM Flow® conductivity depth imaging (CDI) algorithm with associated position, altimeter, magnetic, and derived ground elevation data. Data include the conductivity estimate for each 5 m interval and selected depth slices. These data are in ASCII column format with associated ASEG-GDF2 header files. 3. Gridded data, at 60 or 120 m cell size, for the conductivity depth slices derived from the EM Flow® CDI data, magnetics and elevation data in ER Mapper® binary raster grid format with associated header files. 4. Graphical multiplots, in PDF format, for each flight line showing EM Flow® CDI sections and profiles of electromagnetic data, magnetics, monitors, height and orientation data. 5. Operations Report. 6. Metadata and License files.

At present calcrete-hosted uranium deposits constitute only 1% of Australia's uranium resources. Most known deposits (nine out of eleven) are associated with Cenozoic drainage systems in the Yilgarn Craton, and similar drainage systems in the Gascoyne Province and Ngalia Basin. In the Paterson region calcrete-hosted uranium mineralisation has been reported only in the Lake Waukarlycarly area but no major deposit of this type has yet been found.

A PowerPoint presentation showing regional interpretations of data from the Frome airborne electromagnetic survey, presented at a workshop on 30 November 2011 at the University of Adelaide, South Australia

The 2016 Southern Thomson Orogen VTEM™Plus AEM Survey was conducted by Geoscience Australia as part of a collaborative investigation between the Commonwealth of Australia (Geoscience Australia) and its partners the State of New South Wales (Department of Trade and Investment, Geological Survey of New South Wales) and the State of Queensland (Department of Natural Resources and Mines, Geological Survey of Queensland). The Project aims to better understand the geological character and mineral potential of the southern Thomson Orogen region, focusing on the border between New South Wales and Queensland, by acquiring and interpreting multi-disciplinary geophysical, geochemical and geological data. The primary intended impact of this work is to provide the mineral exploration industry with pre-competitive data and knowledge that reduces risk and encourages mineral exploration in the region. Geoscience Australia contracted Geotech Airborne Pty Ltd to acquire VTEM™Plus AEM data over part of the Southern Thomson Orogen in Queensland and New South Wales in May and June 2016.The data were also processed by Geotech Airborne Ltd using its FullWaveForm® processing techniques. The survey area consists of 2415 line km of time-domain AEM geophysical data acquired in five survey blocks. The majority of traverse lines were spaced at 5000 m in an east-west direction, further details about each blocks flight line specifications can be found in Table 1. The original data supplied by Geotech Airborne Pty Ltd has been modified to contain the final data fields of principal interest, enabling a manageable data file size. This data is available from Geoscience Australia's website free of charge. The comprehensive dataset is available from Geoscience Australia by emailing mineralgeophysics@ga.gov.au. The data release package includes: - Point-located electromagnetic dB/dt and derived B-field data with associated position, altimeter, orientation, magnetic gradiometer, and derived ground elevation data. These data are in ASCII column format with associated README and ASEG-GDF2 header files. The dataset consists of a separate download file for the: - Survey Lines - Repeat lines - Waveform files for every flight containing the 192 kHz sampling of the transmitter current and receiver waveforms. - Point-located conductivity estimates derived using the EM Flow® conductivity depth imaging (CDI) algorithm with associated position, altimeter, orientation, magnetic gradiometer, and derived ground elevation data. Data include the conductivity estimate for each 5 m interval and selected depth slices. - Gridded data, at 1 km cell size in, for the conductivity depth slices derived from the EM Flow® CDI data, magnetics and elevation data in ER Mapper® binary raster grid format with associated header files. - Graphical multiplots, in PDF format, for each flight line showing EM Flow® CDI sections and profiles of Z-component dB/dt data, magnetics, powerline monitor, height and orientation data. - Contractor supplied Operations Report. - ESRI shapefiles and KML files of flight lines. - Metadata and License files.

The National Geochemical Survey of Australia project represents an essential component of the Australian Government's Onshore Energy Security Initiative. The national geochemical survey involves the use of field-tested methods for collection and analysis of transported regolith samples representative of catchments covering most of Australia. The project is a collaboration between Geoscience Australia and State and Northern Territory geoscience agencies, which will provide an internally consistent geochemical dataset useful for calibration and ground-truthing of airborne radiometrics surveys. The survey also will help to fill gaps in current airborne radiometrics and geochemical coverages of Australia, provide multi-element characterisation and ranking of radiometric anomalies and aid in first-order investigation of the nature of geothermal hot-spots. As a result it will support and add value to numerous other Onshore Energy Security Initiative projects and have wider applications in mineral exploration and in environmental assessment and management. This report details the methodology underpinning the determination of the theoretical sampling points using terrain and hydrological analysis; and the protocols for sample collection. It will be used for knowledge transfer during training sessions for the State and Northern Territory field parties who also will receive field equipment and consumables which will ensure there is consistent sampling throughout the project. A digital data entry template has been designed to enable efficient and consistent in-field data capture, which also will streamline data entry into Geoscience Australia's corporate databases.

Data from a VTEM airborne electromagnetic survey over resistive terrain is examined. Forward modelling and analysis of high-altitude lines shows that the amplitudes of random noise, bucking error, processing corrections and geological signals can be large compared to the geological signal in the resistive terrain. The negative impacts of the low geological signal to noise ratio on conductivity estimates generated by layered-earth inversion and conductivity transformations are demonstrated. The reader is alerted to the degree of uncertainty and non-uniqueness that is inherent in conductivity estimates generated from similar datasets.

Real advances in understanding geology for mineral, energy and groundwater resource potential of the Australian continent will come from unveiling what lies at depth, especially in the extensive under-explored regions that are obscured by cover. In this context, airborne electromagnetics (AEM) is a geophysical method at the forefront in addressing the challenge of exploration undercover. In collaboration with the state and territory geological surveys, Geoscience Australia has led a national initiative whose goal is to acquire AEM data at 20 km line spacing across Australia. This initiative, AusAEM, represents the world’s largest AEM survey flown to date; it has covered ~2.5 million km2, a substantial part of northern Australia, and is providing new insights in areas that have not been extensively explored. Regional models of subsurface electrical conductivity derived from AusAEM data support a range of applications that include geological mapping, mineral and petroleum exploration, watershed management and environmental studies. <b>Citation:</b> Ley Cooper, A.Y.. and Brodie, R.C.., 2020. AusAEM: imaging the near-surface from the world’s largest airborne electromagnetic survey. 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.