Legacy product - no abstract available

Airborne hyperspectral data covering about 2500 km2 were obtained from the Eastern Goldfields Superterrane (Yilgarn Craton, Western Australia), which is highly prospective for Archean Au as well as komatiite associated Fe-Ni sulphide mineralisation. In this project hyperspectral airborne data allowed not only the remote mapping of mafic and ultramafic rocks, which are among the main host rocks for Archean Au deposits in the study area, but also the remote mapping of hydrothermal alteration patterns and various geochemical signatures related to the structurally controlled Au mineralisation down to a 4.5 m pixel size. We can reconstruct fluid pathways and their intersections with steep physicochemical gradients, where Au deposition presumably took place, by combining hyperspectral remote sensing with hyperspectral drill core data in 3D mineral maps. White mica mineral maps as well as mineral maps based on the abundance and composition of MgOH and FeOH bearing silicates are the main products for a semi-quantitative assessment of the key alteration minerals in this project. In the southern Selwyn Range, Mount Isa Inlier, Queensland, hyperspectral mineral maps, such as "ferric oxide abundance", "white mica abundance" and "white mica composition", were integrated with geophysical datasets (total magnetic intensity, ternary radiometric imagery). The integration of the datasets enabled us to construct a comprehensive fluid flow model contributing to our understanding of iron-oxide Cu-Au deposits in this region, identifying the source, pathway and depositional sites, which are in good accordance with known deposits.

Hyperspectral images from the Eastern Fold Belt of the Mount Isa Inlier, released by the collaborative Queensland NGMM project between GSQ and CSIRO, were validated as new tool for the detection of IOCG related alteration. High resolution of mineral maps derived from hyperspectral imaging (4.5m/pixel) enables the recognition of various types of hydrothermal alteration patterns and the localisation of fluid pathways. Groundtruthing of a suite of mineral maps was conducted in 2007. Though sample analyses in the lab is still in process, but some preliminary results already show some promising features. In summary hyperspectral images provide a powerful tool for the recognition of various hydrothermal alteration patterns and could be used in combination with other geophysical remote sensing data, such as radiometrics and magnetics. Limitations of this technique are defined by unsatisfactory coverage of mineral maps, man made features, river systems and distribution and composition of debris. A good knowledge of the local geology is necessary to extract the full information provided by the mineral maps. Calibration of ASTER data with the hyperspectral data can hopefully extend interpretation made from the HyMap data into adjacent areas, which are only covered by ASTER. 60pp final report and databases.

This two year collaborative project was established in July 2006 with the overall aim of developing, validating, evaluating and delivering a suite of publicly available, pre-competitive mineral mapping products from airborne HyMap hyperspectral imagery and satellite multispectral ASTER imagery. Moreover, it was important to establish whether these mineral maps would complement other precompetitive geological and geophysical data and provide valuable new information regards enhanced mineral exploration for industry. A mineral systems approach was used to appreciate the value of these mineral maps for exploration. That is, unlocking the value from these mineral maps is not simply by looking for the red bulls-eyes. Instead, mineral products need to be selected on the basis of critical parameters, such as what minerals are expected to develop as fluids migrate from source rocks to depositional sites and then into outflow zones with each associated with different physicochemical conditions (e.g. metasomatic metal budget, nature of the fluids, water-rock ratios, lithostatic pressure, pore fluid pressure, REDOX, pH, and temperature). One of the other key messages is to be able to recognise mineral chemical gradients as well as anomalous cross-cutting effects. These principles were tested using a number of case histories including, (1) the Starra iron oxide Cu-Au deposit; (2) the Mount Isa Pb-Zn-Ag and Cu deposits; and (3) Century Zn, all within the Mount Isa Block. These showed that the interpreted mineral alteration footprints of these mineral systems can be traced 10-15 km away from the metal deposition sites. In summary this project has shown that it is possible to generate accurate, large area mineral maps that provide new information about mineral system footprints not seen in other precompetitive geoscience data and that the vision of a mineral map of Australia is achievable and valuable.

Legacy product - no abstract available

Advanced spectral remote sensing can be a valuable tool for explorers in both green-fields and brown-fields exploration. Using highly-calibrated spectral data and processing techniques, new perspectives can be gained in mapping and characterising materials at the surface. Surface expression of underlying materials, such as ore-deposits, can also be mapped and characterised using these methods. Mineral maps and products made from spectral datasets that can be integrated with other datasets provide a ready-to-use tool that aids explorers in identifying and mapping unconsolidated regolith material and underlying bedrock. In the Mount Isa region, bedrock signatures have been discovered in areas recorded as extensive cover sediments where no bedrock had been previously mapped. This means that in addition to being able to make mineral classifications that characterise transported materials, it is also possible to find new windows of basement geology in areas previously mapped as cover. This has useful applications for mapping geomorphic processes in that it helps to understand mineral dispersion pathways and target surface sampling for mineral exploration. The Predictive Mineral Discovery Cooperative Research Centre (pmd*CRC) developed a comprehensive spectral geology study in conjunction with the Queensland State Government's Smart Exploration Program as part of a joint venture to collect and process new hyperspectral data in Queensland, and to calibrate an existing Advanced Spaceborne Thermal Emission and Reflective Radiometer (ASTER) satellite mosaic, of some ~150 ASTER scenes. This work demonstrated that a considerable amount of geochemical information about hydrothermal deposit "footprints" and alteration chemistry can be acquired by analysing spectral ground response, particularly in the short-wave infra-red where a great deal of mineralogical information is available. Materials which can be mapped include clays and magnesium/iron/aluminium oxyhydroxides, with specific information being obtainable (using higher resolution airborne methods such as HyMap) on mineral composition, abundance and physicochemistries (including crystallinity) for minerals such as kaolinite which can be used as a surrogate for identifying transported vs. in situ material. High resolution mineral maps enable the recognition of various types of hydrothermal alteration patterns and the localisation of fluid pathways, including geochemically discrete alteration shells in IOCG type deposits which correspond to distinct mineral distributions. Potassic alteration in mafic rocks was detected using a combination of MgOH and Fe2+-mineral maps combined with white mica composition and abundance products. MgOH and Fe2+-mineral products were also used to distinguish amphibolites, which form the host rocks for some of the Fe oxide Cu-Au deposits area, from other various mafic rocks.

Identifying and mapping regolith materials at the regional and continental-scale can be facilitated via a new generation of remote sensing methods and standardised geoscience products. The multispectral Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) is the first Earth observation (EO) system to acquire complete coverage of the Australian continent. The Japanese ASTER instrument is housed onboard the USA's Terra satellite, and has 14 spectral bands spanning the visible and near-infrared (VNIR - 500-1,000 nm - 3 bands @ 15 m pixel resolution); shortwave-infrared (SWIR - 1,000-2,500 nm range - 6 bands @ 30 m pixel resolution); and thermal infrared (TIR 8,000-12,000 nm - 90 m pixel resolution) with a 60 km swath. Although ASTER spectral bands do not have sufficient spectral resolution to accurately map the often small diagnostic absorption features of specific mineral species, which can be measured using more expensive 'hyperspectral' systems, current coverage of hyperspectral data is very restricted. The extensive coverage and 30m pixel size of ASTER make it well suited to national scale work. The spectral resolution of ASTER make it best suited to mapping broader 'mineral groups', such as the di-octahedral 'Al-OH' group comprising the mineral sub-groups (and their minerals species) like kaolins (e.g. kaolinite, dickite, halloysite), white micas (e.g. illite, muscovite, paragonite) and smectites (e.g. montmorillonite and beidellite). Extracting mineral group information using ASTER, using specially targeted band combinations, can find previously unmapped outcrop of bedrocks, weathering products, help define soil type and chemistry, and delineate and characterise regolith and landform boundaries over large and remote areas.

Next Generation Mineral Mapping (NGMM) is a CSIRO Minerals Down Under initiative aimed at developing spectral sensing capabilities in collaboration with the government geological agencies across Australia for delivering a new range of pre-competitive geoscience information at low cost to the resources industry. A 2 year multi-organisational project was established in July 2006 and involved the collection of 25000 km2 of airborne HyMap imagery (~250 flight-lines at 5m pixel resolution), over 100 ASTER scenes and associated ground and laboratory validation data collected along major structural/geological corridors across Queensland. This paper will show the effectiveness of software/methods for delivering seamless, accurate mineral and geologic maps from HyMap and ASTER data through comparison with field and laboratory validation data, as well as some geological case histories including. - Geothermometric (metamorphic temperature) mapping using clay physicochemistry; - Local to regional hydrothermal alteration cells associated with the Century Pb-Zn and Starra Au-Cu deposits; and - Associated environmental indicators from remote spectral data for resource development, including dust mapping/monitoring. These results and capabilities also have major implications for mapping soil mineralogy and related properties/processes at local-, catchment- and continental-scales, including soil pH, metal availability, water (content, permeability/runoff), soil loss and organic carbon stocks. The mineral maps and associated data from this project are available on the web (www.em.csiro.au/NGMM).

No abstract available

This product includes the remote sensing information booklet + student activities + one set of five A4 image cards. Discovering Remote Sensing - an introduction does not contain any overhead projection images. Suitable for secondary Years 8-12.