The use of airborne hyperspectral imagery for mapping soil surface mineralogy is examined for the semi-arid Tick Hill test site (20 km2) near Mount Isa in north-western Queensland. Mineral maps at 4.5 m pixel resolution include the abundances and physicochemistries (chemical composition and crystal disorder) of kaolin, illite-muscovite, and Al smectite (both montmorillonite and beidellite), as well as iron oxide, hydrated silica (opal), and soil/rock water (bound and unbound). Validation of these hyperspectral mineral maps involved field sampling (34 sites) and laboratory analyses (spectral reflectance and X-ray diffraction). The field spectral data were processed for their mineral information content the same way as the airborne HyMap data processing. The results showed significant spatial and statistical correlation. The mineral maps provide more detailed surface compositional information compared with the published soil and geology maps and other geoscience data (airborne radiometrics and digital elevation model). However, there is no apparent correlation between the published soil types (i.e. Ferrosols, Vertosols, and Tenosols) and the hyperspectral mineral maps (e.g. iron oxide-rich areas are not mapped as Ferrosols and smectite-rich areas are not mapped as Vertosols). This lack of correlation is interpreted to be related to the current lack of spatially comprehensive mineralogy for existing regional soil mapping. If correct, then this new, quantitative mineral mapping data has the potential to improve not just soil mapping but also soil and water catchment monitoring and modeling at local to regional scales. The challenges to achieving this outcome include gaining access to continental-scale hyperspectral data and models that link the surface mineralogy to subsurface soil characteristics/processes.

The National Geochemical Survey of Australia (NGSA) project has collected catchment outlet sediment samples from 1315 sites located in 1186 catchments (~10% of which were sampled in duplicate) covering over 80% of Australia, in a collaborative venture between Geoscience Australia and the geoscience agencies of all States and the Northern Territory. At each site, composited samples were collected from two depth intervals: (1) the Top Outlet Sediment from 0-10 cm depth, and (2) the Bottom Outlet Sediment from 60-80 cm depth on average. In the laboratory, the samples were dried, homogenised and separated into two grain-size fractions: (1) a 'coarse' fraction (0-2 mm), and (2) a 'fine' fraction (0-75 um). All together, thus, 5260 samples were prepared for analysis. Bulk splits were also separated for the determination of bulk properties. Samples were analysed for up to 68 chemical elements after Total, Aqua Regia and Mobile Metal Ion digestion methods. Several quality control measures were taken throughout the project and the data quality was assessed in a separate report. This report used the acquired geochemical data to investigate the preliminary implications of this new national dataset on exploration for energy and mineral resources in Australia. This was mostly done by overlaying the NGSA data on coverages of known deposits and occurrences for selected commodities: uranium (U), thorium (Th), gold (Au), copper (Cu), lead (Pb), zinc (Zn) and Rare Earth Elements (REEs). For U, an attempt was made to distinguish between calcrete-related and intrusion-related deposit types, and a local case study in the Pine Creek area is also presented. For Zn, preliminary results from an investigation into discrete field modelling using concentration-area (CA) fractal plots are also presented. Coincidence of known mineral deposits and occurrences with elevated geochemical element concentrations in the same catchment are highlighted. Several catchments have elevated geochemical element concentrations in catchments with no known mineral deposits or occurrences, which provide potential targets for exploration. This technique constitutes a useful and rapid tool for area selection where further, more detailed exploration effort could be expended to test these geochemical anomalies.

A new continental-scale geochemical atlas and dataset for Australia were officially released into the public domain at the end of June 2011. The National Geochemical Survey of Australia (NGSA) project, which started in 2007 under the Australian Government's Onshore Energy Security Program at Geoscience Australia, aimed at filling a huge knowledge gap relating to the geochemical composition of surface and near-surface materials in Australia. Better understanding the concentration levels and spatial distributions of chemical elements in the regolith has profound implications for energy and mineral exploration, as well as for natural resource management. In this world first project, a uniform regolith medium was sampled at an ultra-low density over nearly the entire continent, and subsamples from two depths and two grain-size fractions were analysed using up to three different (total, strong and weak) chemical digestions. This procedure yielded an internally consistent and comprehensive geochemical dataset for 68 chemical elements (plus additional bulk properties). From its inception, the emphasis of the project has been on quality control and documentation of procedures and results, and this has resulted in eight reports (including an atlas containing over 500 geochemical maps) and a large geochemical dataset representing the significant deliverables of this ambitious and innovative project. The NGSA project was carried out in collaboration with the geoscience agencies from every State and the Northern Territory under National Geoscience Agreements. .../...

Soil mapping at the local- (paddock), to continental-scale, may be improved through remote hyperspectral imaging of surface mineralogy. This opportunity is demonstrated for the semiarid Tick Hill test site (20 km2) near Mount Isa in western Queensland. The study of this test site is part of a larger Queensland government initiative involving the public delivery of 25,000 km2 of processed airborne hyperspectral mineral maps at 4.5 m pixel resolution to the mineral exploration industry. Some of the mineral maps derived from hyperspectral imagery for the Tick Hill area include the abundances and/or physicochemistries (chemical composition and crystal disorder) of dioctahedral clays (kaolin, illite-muscovite and Al smectite, both montmorillonite and beidellite), ferric/ferrous minerals (hematite/goethite, Fe2+-bearing silicates/carbonates) and hydrated silica (opal) as well as soil water (bound and unbound) and green and dry (cellulose/lignin) vegetation. Validation of these hyperspectral mineral products is based on field soil sampling and laboratory analyses (spectral reflectance, X-ray diffraction, scanning electron microscope and electron backscatter). The mineral maps show more detailed information regarding the surface composition compared with the published soil and geology (1:100,000 scale) maps and airborne radiometric imagery (collected at 200 m line spacing). This mineral information can be used to improve the published soil mapping but also has the potential to provide quantitative information suitable for soil and water catchment modeling and monitoring.

Introduction Low-density geochemical surveys provide a cost-effective means to assess the composition of near-surface materials over large areas. Many countries in the world have already compiled geochemical atlases based on such data. These have been used for a number of applications, including: - establish baselines from which future changes can be measured - design geologically sensible targets for remediation of contaminated sites - support decision-making regarding appropriate land-use - explore for natural resources - study links between geology and plant/animal health (geohealth) A first pilot project was initiated to help establish sampling and analytical protocols relevant to Australian landscapes and climates. The Riverina region was chosen for this study because of its crucial economic, environmental and societal importance within the Murray-Darling basin. The region is a prime agricultural area, is bordered to the south by the Victorian goldfields, and is home to 11% of the Australian population. Results of this study are presented here. Methods Using a hydrological analysis, 142 sites near the outlets of large catchments were selected within the 123,000 km2 survey area (1 site per 866 km2 on average). At each site, two 10-cm thick overbank sediment samples were taken, one at the surface ('top overbank sediment', TOS) and the other between 60 and 90 cm depth (`bottom overbank sediment', BOS). These were described, dried, sieved (<180 m) and analysed chemically for 62 elements. Exploratory data analysis was undertaken and geochemical maps (various styles are shown here) were prepared. Results and discussion The geology of the area is dominated by Cainozoic sediments found in low-relief plains over the vast majority of the Riverina. The eastern and southern fringes of the area form higher relief landforms developed on outcropping or subcropping Palaeozoic sedimentary, mafic and felsic volcanic and felsic intrusive rocks. The geochemical results of the survey are independently corroborated by the good match between the distributions of K, U and Th concentrations in TOS and airborne gamma-ray maps. The distribution of Ca in BOS indicates generally higher concentrations in the northern part of the study area, which is also reflected in higher soil pH values there. Such data have implications for soil fertility and management in agricultural areas. In terms of applications to mineral exploration, dispersion trains of typical pathfinder elements for gold mineralisation, like As and Sb are clearly documented by the smoothly decreasing concentrations from south (near the Victorian goldfields) to north (over sediments from the Murray basin). Chromium is an element that can be associated with ill-health in animals and humans when present over certain levels. There is a smooth increase in Cr concentration from north to south, and the two sites with the highest values can be correlated with a ridge of Cambrian mafic volcanics. High total Cr concentrations in the Riverina are unlikely, however, to lead to serious health problems as only a very small proportion of Cr will be bioavailable. Conversely, some elements can be present at concentrations that are too low for optimum plant growth, such as potentially Mo. The distribution map for this element shows a general decrease from south to north. Given its lower bioavailability in acid soils, Mo is likely to be deficient in the south of the region, despite higher total concentrations here. Farmers report the necessity to use Mo-enriched fertilisers in this area. Conclusions Low-density geochemical surveys can be conducted in Australia using common regolith sampling media. They provide a cost-effective, internally consistent dataset that can be used by to support a variety of critical economic, environmental and societal decisions.

Spectral data from airborne and ground surveys enable mapping of the mineralogy and chemistry of soils in a semi-arid terrain of Northwest Queensland. The study site is a region of low relief, 20 km southeast of Duchess near Mount Isa. The airborne hyperspectral survey identified more than twenty surface components including vegetation, ferric oxide, ferrous iron, MgOH, and white mica. Field samples were analysed by spectrometer and X-ray diffraction to test surface units defined from the airborne data. The derived surface materials map is relevant to soil mapping and mineral exploration, and also provides insights into regolith development, sediment sources, and transport pathways, all key elements of landscape evolution.

The present report is a compilation of 531 geochemical maps that result from the National Geochemical Survey of Australia. These constitute the first continental-scale series of geochemical maps based on internally consistent, state-of-the-art data pertaining to the same sampling medium collected, prepared and analysed in a uniform and well documented manner and over a short time period (four years). Interpretations of the data and maps will be published separately.

From 2007 to 2009, the National Geochemical Survey of Australia (NGSA) project collected sediment samples from 1315 sites located in 1186 catchments (~10 % of which were sampled in duplicate) from across Australia. Overbank sediments were chosen as sampling media, with a near-surface sample (Top Outlet Sediment, TOS, from 0-10 cm below the surface) and a bottom sample (Bottom Outlet Sediment, BOS, ~10 cm interval between approximately 60-80 cm below the surface) being collected. The sample sites were selected to be near outlets or spill points of large catchments, so that overbank sediments there could reasonably be assumed to represent well-mixed, fine-grained composite samples of all major rock and soil types present in the catchment. Sample sites and their corresponding sediment samples were subjected to a detailed description and the determination of bulk parameters in the field (texture, moist and dry colour, field pH). This is complemented by a series of laboratory measurements and analyses reported elsewhere. This report documents the complete field dataset and discusses the pH and soil colour data that were collected in the field. At the time of writing, field pH and colour are the only datasets available for all sites. Maps are presented showing the spatial distribution of these data in both TOS and BOS samples. These data will be the basis of further interpretative work.

Geoscience Australia and CO2CRC have constructed a greenhouse gas controlled release reference facility to simulate surface emissions of CO2 (and other GHG gases) from an underground slotted horizontal well into the atmosphere under controlled conditions. The facility is located at an experimental agricultural station maintained by CSIRO Plant Industry at Ginninderra, Canberra. The design of the facility is modelled on the ZERT controlled release facility in Montana. The facility is equipped with a 2.5 tonne liquid CO2 storage vessel, vaporiser and mass flow controller unit with a capacity for 6 individual metered CO2 gas streams (up to 600 kg/d capacity). Injection of CO2 into soil is via a shallow (2m depth) underground 120m horizontally drilled slotted HDPE pipe. This is equipped with a packer system to partition the well into six CO2 injection chambers. The site is characterised by the presence of deep red and yellow podsolic soils with the subsoil containing mainly kaolinite and subdominant illite. Injection is above the water table. The choice of well orientation based upon the effects of various factors such as topography, wind direction, soil properties and ground water depth will be discussed. An above ground release experiment was conducted from July - October 2010 leading to the development of an atmospheric tomography technique for quantifying and locating CO2 emissions1. This technique will be applied to the first sub-surface experiment held in January-March 2012 in addition to soil flux surveys, microbiological surveys, and tracer studies. An overview of monitoring experiments conducted during the subsurface release and preliminary results will be presented. Additional CO2 releases are planned for late 2012 and 2013. Abstract for "11th Annual Conference on Carbon Capture Utilization & Sequestration" April 30 - May 3, 2012, Pittsburgh, Pennsylvania

A new continental-scale geochemical atlas and dataset were officially released into the public domain at the end of June 2011. The National Geochemical Survey of Australia (NGSA) project, which started in 2007 under the Australian Government's Onshore Energy Security Program at Geoscience Australia, aimed at filling a huge knowledge gap relating to the geochemical composition of surface and near-surface materials in Australia. Better understanding the concentration levels and spatial distributions of chemical elements in the regolith has profound implications for energy and mineral exploration, as well as for natural resource management. In this world first project, a uniform regolith medium was sampled at an ultra-low density over nearly the entire continent, and subsamples from two depths and two grain-size fractions were analysed using up to three different (total, strong and weak) chemical digestions. This procedure yielded an internally consistent and comprehensive geochemical dataset for 68 chemical elements (plus additional bulk properties). From its inception, the emphasis of the project has been on quality control and documentation of procedures and results, and this has resulted in eight reports (including an atlas containing over 500 geochemical maps) and a large geochemical dataset representing the significant deliverables of this ambitious and innovative project. The NGSA project was carried out in collaboration with the geoscience agencies from every State and the Northern Territory under National Geoscience Agreements. .../...