The purpose of the volume is to provide source material for students, geologists and geophysicists in the form of a collection of brief articles on geophysical and remote sensing methodologies suitable for regolith exploration. The articles do not contain detailed information on how each method works, but are rather intended as a guide to selecting the appropriate method for a particular exploration or environmental problem. A number of factors contributed to the initiation of this project. Firstly, a realisation that there is very little material available on regolith geophysics that could be used by mineral exploration professionals to make important decisions about the application or deterrence of certain geophysical or remote sensing techniques. Secondly, the scarcity of material on this topic that can be used for teaching purposes at undergraduate university level. Thirdly, the success of Brad Pillans’ booklet titled “Regolith dating methods”, a CRC LEME publication, showed that there is a lot of interest among the professional community in practical, off-the-shelf material in regolith exploration methodologies. The booklet contains twelve articles. Each article describes a remote sensing or a geophysical technique suitable for regolith exploration. The papers are organised in a similar structure, with the intention of aiding the reader in the comparison of the methods. After a brief general description, the advantages and pitfalls of each method are presented, as well as the likely product of a survey. This is followed by one or more case histories, the organisational requirements of a field survey, the likely costs, and finally addresses of the main organisations providing the service. We believe that with this volume CRCLEME is providing a service to the exploration and environmental geophysics community as well as providing a valuable aid for teaching mineral exploration students.

We present a new method for the inversion of airborne gamma-ray spectrometric line data to a regular grid of radioelement concentration estimates on the ground. The method incorporates the height of the aircraft, the 3D terrain within the field of view of the spectrometer, the directional sensitivity of rectangular detectors, and a source model comprising vertical rectangular prisms with the same horizontal dimensions as the required grid cell size. The top of each prism is a plane surface derived from a best-fit plane to the digital elevation model of the earth's surface within each grid cell area. The method is a significant improvement on current methods, and gives superior interpolation between flight lines. It also eliminates terrain effects that would normally remain in the data with the use of conventional gridding methods.

This job is part of the town capture program

We present a new method for the inversion of airborne gamma-ray spectrometric line data to a regular grid of radioelement concentration estimates on the ground. The method incorporates the height of the aircraft, the 3D terrain within the field of view of the spectrometer, the directional sensitivity of rectangular detectors, and a source model comprising vertical rectangular prisms with the same horizontal dimensions as the required grid cell size. The top of each prism is a plane surface derived from a best-fit plane to the digital elevation model of the earth's surface within each grid cell area. The method is a significant improvement on current methods, and gives superior interpolation between flight lines. It also eliminates terrain effects that would normally remain in the data with the use of conventional gridding methods.

Lagrangian stochastic (LS) forward modelling of CO2 plumes from above-surface release experiments conducted at the GA-CO2CRC Ginninderra GHG controlled release facility demonstrated that small surface leaks are likely to disperse rapidly and unlikely to be detected at heights greater 4 m; this was verified using a rotorcraft to map out the plume. The CO2 sensing rotorcraft unmanned aerial vehicle (RUAV) developed at the Australian National University, Canberra, is equipped with a CO2 sensor (3 ppm accuracy and 2 s response time), a GPS, lidar and a communication module. It was developed to detect, locate and quantify CO2 gas leaks. The choice of a rotorcraft UAV allows slower flight speeds compared to speeds of a fixed-wing UAV; and the electric powered motor enables flight times of 12 min. During the experiments, gaseous CO2 (100 kg per day) was released from a small diffuse source located in the middle of the paddock of the controlled release facility, and the RUAV, flying repeatedly over the CO2 source at a few metres height, recorded CO2 concentrations up to 85 ppm above background. Meteorological parameters measured continuously at the site were input in the LS model. Mapped out horizontal and vertical CO2 concentrations established the need to be close to the ground in order to detect CO2 leakage using aerial techniques. Using the rotorcraft as a mobile sensor could be an expedient mechanism to detect plumes over large areas, and would be important for early detection of CO2 leaks arising from CO2 geological storage activities.

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.

Geoscience Australia’s Historical Aerial Photography Program currently involves scanning and georeferencing old flight diagrams to enable the digitising and positioning of historical aerial photographs for easy discovery and download. Accurate digital mapping of GA’s aerial photography collection will make catalogue searches easier and the collection more accessible to the public. This story map presents an interactive history of aerial photography, a background of aerial photography in Australia, historical aerial photography use cases and scenarios, and a background on Geoscience Australia's program to digitise flight diagrams and create a catalogue of aerial photographs.

The Aerial Survey Photography Records consist of more than 11,000 film negatives as well as derivative contract prints and diapositives. These records of the Australian landscape were created by Geoscience Australia and its predecessor agencies such as the Australian Surveying and Land Information Group, the Australian Survey Office and the Division of National Mapping. The records were captured during the period c.1928-1993 and have been used as the basis for the Commonwealth government's topographic map production as well as providing an opportunity to track environmental changes in the landscape over an extensive period of time. Antarctic films are also included in the collection. The entire collection was transferred to National Archives Australia in December 2010.