Identification of neotectonic features in Australia's interior is challenging with a lack of outcrop, and a subtlety in surface expression that is only recently being detected using high resolution surface elevation mapping methods. Many more geologically-recent tectonic features are completely buried with no present-day surface expression. In this study, airborne electromagnetics (AEM) and high resolution LiDAR datasets were acquired as part of 3D mapping of the hydrogeology in the Darling Floodplain. Neotectonic faulting and uplift has previously been described in the Broken Hill area, and along the north-western margin of the Murray Basin, along the Darling Lineament. The AEM data (acquired over an area of 7,500 sq km), validated by 100 new boreholes, reveal that an important Pleistocene aquitard (Blanchetown Clay) confining the main aquifer of interest (Calivil Formation), has an undulating surface, which is locally sharply offset. Gridding of the interpreted top surface suggests that it has been affected by local warping and faulting, as well as regional tilting due to basin subsidence or margin uplift. Some of the up-warped areas are associated with local landscape highs, suggesting relatively recent movement. Overall, the top surface of the Blanchetown Clay varies in elevation by 60m, with important implications for groundwater flow and recharge dynamics. This study also illustrates that the zone of tectonic activity can be extended southeast from the Broken Hill area to the Darling Floodplain, and that the area of seismic hazard associated with the Darling Lineament may be broader than previously anticipated.

Under the Community Stream Sampling and Salinity Mapping Project, the Australian Government through the Department of Agriculture, Fisheries and Forestry and the Department of Environment and Heritage, acting through Bureau of Rural Sciences, funded an airborne electromagnetic (AEM) survey to provide information in relation to land use questions in selected areas along the River Murray Corridor (RMC). The proposed study areas and major land use issues were identified by the RMC Reference Group at its inception meeting on 26th July, 2006. This report has been prepared to facilitate recommendations on the Nangiloc - Colignan study area. The work was developed in consultation with the RMC Technical Working Group (TWG) to provide a basis for the RMC Reference Group and other stake holders to understand the value and application of AEM data to the study area. This understanding, combined with the Reference Group's assessment of the final results and taking in account policy and land management issues, will enable the Reference Group to make recommendations to the Australian Government.

Under the Community Stream Sampling and Salinity Mapping Project, the Australian Government through the Department of Agriculture, Fisheries and Forestry and the Department of Environment and Heritage, acting through Bureau of Rural Sciences, funded an airborne electromagnetic (AEM) survey to provide information in relation to land use questions in selected areas along the River Murray Corridor (RMC). The proposed study areas and major land use issues were identified by the RMC Reference Group at its inception meeting on 26th July, 2006. This report has been prepared to facilitate recommendations on the Robinvale - Boundary Bend study area. The work was developed in consultation with the RMC Technical Working Group (TWG) to provide a basis for the RMC Reference Group and other stake holders to understand the value and application of AEM data to the study area. This understanding, combined with the Reference Groups assessment of the final results and taking in account policy and land management issues, will enable the Reference Group to make recommendations to the Australian Government.

A new Geoscience Australia Magnetic Anomaly Grid Database of Australia (MAGDA) has been developed. This database contains publicly available airborne magnetic grid data for on- and near-offshore Australia. Flight-line magnetic data for each survey have been optimally gridded and the grids matched in one inverse process. New composite grids at 250 m and 400 m grid spacing form the basis of the new fourth edition of the Magnetic Anomaly Map of Australia. Aeromagnetic traverses flown around Australia during 1990 and 1994 are used in both quality control of the grids they intersect, and also to constrain grid merging by forcing grid data, where intersected, to the level of the traverse data. Although matching and merging of many grids into a seamless compilation produces a pleasing result, without obvious short-wavelength artefacts, accurate long wavelength components of crustal origin are more difficult to obtain. Errors in the ?tilt? of individual surveys, due either to older instrumentation, errors in processing, or incomplete core-field removal, can lead to large long wavelength errors when hundreds of surveys are combined across thousands of kilometres. Quantification of the accuracy of long-wavelength components is only possible by comparison with independent datasets. A low-pass filtered composite grid of the Australian region has been compared with CHAMP satellite magnetic data, and shows a considerable improvement in the correlation of long wavelength components compared with the previous edition

Airborne electromagnetic data (AEM) are used in many and diverse applications such as mineral and energy exploration, groundwater investigations, natural hazard assessment, agriculture, city planning and defence. Unfortunately, many users do not have access to a simple workflow for assessing the quality of the data that they are using. This poster outlines the main quality assurance and quality control (QA-QC) procedures used by Geoscience Australia for our 2008-11 AEM surveys. Minor processing errors can dramatically reduce the quality of the data to the point that interpreters will be unable to use the data, or worse still, will be misled by features or characteristics produced during acquisition and processing. These scenarios not only impact the application at the time of interpretation, but can seriously impact the reputation and perceptions of the AEM industry. Every effort should be made to ensure that maximum fidelity is preserved in the data during acquisition and processing so that the best possible data are available for interpretation. Geoscience Australia is embarking on a project to upgrade the National Airborne Geophysical Database to better manage the data from major AEM surveys. This will better preserve the data and associated documentation to allow users to access and take advantage of the data well into the future. The quality of historical data included in this endeavour will unfortunately be variable and dependent on the QA-QC standards of the time. Geoscience Australia currently holds over 150 000 line kilometres of AEM data funded by the Commonwealth Government, State Governments and industry. Much of this data is available online for download, but is not available via the Geophysical Archive Data Delivery System (GADDS). Geoscience Australia is planning the expansion of GADDS to accommodate AEM data into the future. It is hoped the procedures outlined on the poster will be widely accepted by users, in particular new users, as a set of minimum requirements to help ensure that AEM data will be of a consistent quality and to a higher standard acknowledging it as the valuable resource it is. Key words: Airborne electromagnetic data; National Airborne Geophysical Database; AEM; QA-QC.

Airborne electromagnetic (AEM) systems are increasingly being used for mapping conductivity in areas susceptible to secondary salinity, with particular attention on near-surface predictions (ie those in the top 5 or 10 metres). Since measured AEM response is strongly dependent on the height of both the transmitter loop and receiver coil above conductive material, errors in measurements of terrain clearance translate directly into significant errors in predicted near-surface conductivity. Radar altimetry has been the standard in airborne geophysical systems for measuring terrain clearance. In areas of agricultural activity significant artifacts up to five metres in magnitude can be present. One class of error, related to surface roughness and soil moisture levels in ploughed paddocks and hence termed the ?paddock effect?, results in overestimation of terrain clearance. A second class of error, related to dense vegetation and hence termed the ?canopy effect?, results in underestimation of terrain clearance. A survey example where terrain clearance was measured using both a radar and a laser altimeter illustrates the consequences of the paddock and canopy effects on shallow conductivity predictions. The survey example shows that the combination of the dependence of AEM response on terrain clearance and systematic radar altimeter artefacts spatially coincident with areas of differing land-use may falsely imply that land-use practices are the controlling influence on conductivity variations in the near surface. A laser altimeter is recommended for AEM applications since this device is immune to the paddock effect. Careful processing is still required to minimise canopy effects.

During 2008 and 2009, and under the Australian Government's Onshore Energy Security Initiative, Geoscience Australia acquired airborne electromagnetic (AEM) data over the Pine Creek Orogen of the Northern Territory. The survey area was split into three areas for acquisition. VTEM data was acquired in the Kombolgie area east of Kakadu National Park (this data set) between August and November 2008. TEMPEST data was acquired west of Kakadu National Park with the area split in two to facilitate the use of two aircraft: the Woolner Granite area in the north was acquired between October and December 2008; and the Rum Jungle area adjoining to the south, was acquired between October 2008 and May 2009. The main purpose of the surveys was to provide additional geophysical/geological context for unconformity style uranium mineral systems and thereby promote related exploration. The survey data will also provide information on depth to Proterozoic/Archean basement, which is of general interest to explorers, and will be used as an input into ground water studies in the region. This dataset includes the subscriber company data K1 K2 and K3.

This report summarises the result of a study into seawater intrusion into coastal aquifers in the Northern territory coastal plain using AEM data, down hole geophysics, and bore hole geology carried out by Geoscience Australia on behalf of the National Water Commission and in partnership with NRETAS. The study showed that ground-validated AEM is able to map areas of saline aquifers in the area and differentiate them from bedrock conductors.

During 2008 and 2009, and under the Australian Government's Onshore Energy Security Initiative, Geoscience Australia acquired airborne electromagnetic (AEM) data over the Pine Creek Orogen of the Northern Territory. The survey area was split into three areas for acquisition. VTEM data was acquired in the Kombolgie area east of Kakadu National Park between August and November 2008. TEMPEST data was acquired west of Kakadu National Park with the area split in two to facilitate the use of two aircraft: the Woolner Granite area in the north (this data set) was acquired between October and December 2008; and the Rum Jungle area adjoining to the south, was acquired between October 2008 and May 2009. The main purpose of the surveys was to provide additional geophysical/geological context for unconformity style uranium mineral systems and thereby promote related exploration. The survey data will also provide information on depth to Proterozoic/Archean basement, which is of general interest to explorers, and will be used as an input into ground water studues in the region.

The GILMORE project is a pilot study designed to test holistic systems approaches to mapping mineral systems and dryland salinity in areas of complex regolith cover. The project is coordinated by the Australian Geological Survey Organisation, and involves over 50 scientists from 14 research organisations. Research partners include: Cooperative Research Centres for Advanced Mineral Exploration Technologies (CRC AMET), Landscape Evolution and Mineral Exploration (CRC LEME), the CRC for Sensor Signal and Information Processing, and the Australian Geodynamics Cooperative Research Centre (AGCRC) Land and Water Sciences Division of Bureau of Rural Sciences (BRS) NSW Department of Land & Water Conservation and the NSW Department of Mineral Resources. Various universities including the Australian National University, University of Canberra, Macquarie University, Monash University, University of Melbourne, and Curtin University of Technology, and Australian National Seismic Imaging Resource (ANSIR). The project area lies on the eastern margin of the Murray-Darling Basin in central-west NSW. The project area was chosen for its overlapping mineral exploration (Au-Cu) and salinity management issues, and the availability of high-resolution geophysical datasets and drillhole materials and datasets made available by the minerals exploration industry. The project has research agreements with the minerals exploration industry, and is collaborating with rural land-management groups, and the Grains Research and Development Corporation. The study area (100 x 150 km), straddles the Gilmore Fault Zone, a major NNW-trending crustal structure that separates the Wagga-Omeo and the Junee-Narromine Volcanic Belts in the Lachlan Fold Belt. The project area includes tributaries of the Lachlan and the Murrumbidgee Rivers, considered to be two of the systems most at risk from rising salinities. This project area was chosen to compare and contrast salt stores and delivery systems in floodplain (in the Lachlan catchment) and incised undulating hill landscapes (Murrumbidgee catchment). The study area is characteristic of other undulating hill landscapes on the basin margins, areas within the main and tributary river valleys, and the footslopes and floodplains of the Murray-Darling Basin itself. Studies of the bedrock geology in the study area reveal a complex architecture. The Gilmore Fault Zone consist of a series of subparallel, west-dipping thrust faults, that juxtapose, from west to east, Cambro-Ordovician meta-sediments and granites of the Wagga Metamorphics, and further to the east, a series of fault-bounded packages comprising volcanics and intrusions, and siliciclastic meta-sediments. Two airborne electromagnetic (AEM) surveys were flown in smaller areas within the two catchments. Large-scale hydrothermal alteration and structural overprinting, particularly in the volcanics, has added to the complexity within the bedrock architecture. The data were originally published on 6 CDs. For ease of download the data have been zipped into the original structure. The contents are as follows: CD1 - An overview of the GILMORE Project with geophysical images, regolith map, drillhole locations, geophysical survey information and maghemite geochemistry. CD2 - Airborne Electromagnetic (AEM) images from the TEMPEST survey with vertical cross-sections linked to the flight lines CD3 - Integrated images of the Airborne Electromagnetic (AEM) data draped over the First Vertical Derivative of the Total Magnetic Intensity CD4 - Integrated images of the Airborne Electromagnetic (AEM) data draped over the First Vertical Derivative of the Total Magnetic Intensity CD5 - High resolution geophysical images from three detailed surveys and data from the Airborne Electromagnetic (AEM) QUESTEM survey CD6 - Geology, geochemistry, downhole data, 3 dimensional models, seismic data, and images linked to downhole point data.