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  • 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).

  • A test survey was made with a Radore Equipment over three mineralised areas in Tasmanian. The investigations were made in January, 1955 for the purpose of comparing the performance of the Radore equipment with that of lower-frequency electromagnetic equipment previously used successfully over the same areas. The results show that although some very weak indications were recorded by the Radore equipment, it has not been possible to correlate these satisfactorily with the know mineralisation. Moreover, it is difficult to distinguish indications that may possibly be due to mineralisation from apparent indications that are undoubtedly due to irregularities in topography.

  • 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.

  • Two methods are outlined in this report. The first, is a method intended for the determination of porosity of consolidated sediments. The method is applicable to those sediments included in rotary drill cores and hand specimens of rock collected in the field. The second, is a method intended for the determination of permeability. It is applicable to suitably sized samples of rocks and any other substances whose constitutions permit of their being treated by the procedure set out in this method, subject to their own inherent limitations relative to this method. This report provides a detailed description of each of these methods.

  • The deposits of heavy mineral sands along the East Coast of Australia are being investigated primarily to determine their content of monazite. These deposits contain most of the known world reserves of zircon and rutile for which they are being exploited at various localities. Monazite, a phosphate of cerium, lanthanum, praseodymium and other rare earths, with thorium silicate, is utilised commercially as a source of cerium and of thorium. In this investigation, the thorium content on the monazite is being determined on the basis of its radioactivity. A principal deposit, and two smaller deposits, in the Fingal-Cudgen area were investigated. The geology of the area, methods of testing, and the results of the investigation are discussed in this report.

  • This report gives an overview of the bauxite resources of the Inverell district, New South Wales, including, in particular, those deposits held or examined by the Australian Aluminium Production Commission. A description of each deposit is given, which includes information on the geology of the area, grade of bauxite, and production figures. Figures are given for the proven reserves of economic bauxite in the district.

  • A number of Paleoproterozoic layered mafic-ultramafic intrusions in the central part of the Halls Creek Orogen of East Kimberley, Western Australia, have been explored for platinum-group elements (PGE), chromium, nickel, copper, cobalt and gold. Here we report on the halogen geochemistry of apatite and biotite in a number of these intrusions. Interstitial apatite is ubiquitous in these intrusions and, in most samples, tends to be relatively enriched in F- and OH-endmembers and relatively poor in Cl (< 20 mole %). Fluorapatite occurs in the more evolved igneous rocks and in marginal samples that apparently have been contaminated by metamorphic country rock. Cl/F ratios generally increase with bulk rock molar Mg/(Mg + Fe) ratios, as observed in other intrusions. Only a few samples show Cl-enrichment as high as that seen in the Stillwater and Bushveld complexes beneath the major stratabound PGE deposits. The most Cl-rich compositions observed occur in the upper part of the Springvale intrusion, where it is associated with troctolite, and in a single sample from the McIntosh intrusion. For the former intrusion, it is suggested that volatiles migrating out of the lower part of the mafic stratigraphy stabilized olivine at the expense of pyroxene. Associated biotite tends to be low in both Cl and F, containing no more than 10 mole % of these components. It is concluded that the East Kimberley intrusions contained a low to moderate volatile component that, during the combined processes of crystallization, degassing and fractionation of interstitial halogen-bearing minerals, was able to produce a late, mobile interstitial silicate liquid or volatile-rich fluid phase of variable Cl/F content that gave rise to most of the observed variations within any given intrusion. The exceptions include some marginal samples that appear to have been affected by country rocks, either during emplacement (assimilation) or during later metamorphism. The generally low Cl/F ratio of apatite, the lack of primary amphibole and the high background sulfur concentrations of the East Kimberley intrusions suggest that these magmas were relatively dry. The possible development of high-grade, PGE-enriched horizons by late-stage hydrothermal processes that could have mobilized significant amounts of the PGE and sulfur is considered to be of low potential.

  • The primary aim of the investigation was to determine the reserves and distribution of monazite in the deposits of heavy mineral sands along the East Coast. These deposits contain most of the known world reserves of zircon and rutile for which they are being exploited at various localities, mainly from North Stradbroke Island in Queensland to Ballina in New South Wales. Monazite forms little more than 0.5 per cent of the mixed concentrates, but can be recovered as a by-product from the separation of the other minerals. The monazite forms a source of supply of cerium and also of thorium. The thorium content of the monazite is determined on the basis of its radioactivity. This report gives an account of the field and laboratory work carried out. The results of the laboratory work, which included the separation and examination of minerals, the radiometric determination of quantities of monazite, and the investigation of the thoria content of monazite, are described in this report.

  • Evaporites comprise all deposits formed by the evaporation of water and the precipitation of its constituents, such as calcium sulphate, sodium chloride, and potassium compounds. They may be found as rock-gypsum, anhydrite, rock-salt or potash-salt deposits at depth in pre-Recent geological series, or as Recent formations of gypsum and salt on the surface. The main object of this report is to show the conditions under which evaporite sediments are formed, what salt deposits are to date known in Australia, where rock-gypsum, rock-salt and potash-salt deposits may be expected within pre-Recent formations, and how further investigations should be carried out.

  • Bauxite was found on Manus Island in 1952 by J.E. Thompson, Senior Resident Geologist, Territory of Papua and New Guinea, at three separate localities. At Lepatuan a dacite flow overlies bedded tuffs and both have been bauxitized. The former parent rock yields a porous granular bauxite containing about 1 percent silica, 55 percent alumina, 10-13 percent ferric oxide and 1 percent titania. Bauxite developed on the tuffs is nodular in character, and consists of gibbsite nodules embedded in soft clay-like bauxite. The composition of one sample of this bauxite is 11.7 percent silica, 51.0 percent alumina, 10.8 percent ferric oxide and 1.0 percent titania. The bauxite is forming at the present day by direct alteration of the dacite without an intervening clay zone, but the tuffs are kaolinized in the first stage of alteration. It is of high significance that bauxite can develop on small flat elevated areas (50 acres at Lepatuan) during the present weathering cycle. Essential conditions for bauxitic alteration to take place appear to be - (a) high mean temperature, high rainfall and dense vegetation, (b) relatively flat terrain, and (c) elevation above immediate surroundings to ensure adequate ground-water movement. Total resources of bauxite at Lepatuan are about 600,000 tons, and possible reserves are negligible at the other localities. Difficulties of access and distance from markets militate against commercial exploitation of the deposit, but prospects of finding more bauxite in the islands of the volcanic arcs of Bismark Archipelago cannot be lightly dismissed.