Legacy product - no abstract available

Legacy product - no abstract available

The potential for geochemical reactions to cause aquifer clogging or detrimental water quality changes was assessed for a managed aquifer recharge (MAR) target in the Darling River floodplain. The assessment used ambient groundwater quality from the target Calivil Formation aquifer, as well as from the shallow unconfined aquifers; Darling River source water quality; and mineralogy and geochemistry of sonic-cored aquifer samples. PHREEQC was used to examine the impact of mixing and interaction between these end-members. There is considerable variability in the redox state within the Calivil aquifer, with groundwater pe values ranging from -6 to 8. PHREEQC simulations using the median pe value of 3 resulted in super-saturation with respect to Fe(OH)3 . Hence, injection of an oxygenated source water into anoxic zones within the target aquifer can result in iron clogging due to precipitation of any source water dissolved iron and any Fe(II) oxidation in the sediments (in pyrite or displaced from exchange sites). The amount of Fe(II) within the storage zone available to be oxidised is unknown and may be limited given that Fe(III) oxides were present in the core material. The aquifer material contains species that may be released during MAR, including aluminium, arsenic, fluoride, iron, manganese, molybdenum, nickel, selenium and uranium. Injection of source water with elevated dissolved organic carbon (DOC) could enhance metal and metalloid release through reductive dissolution of iron oxides within the storage zone. The fate of any mobilised trace species would be dictated by storage zone redox conditions. Arsenic and molybdenum are likely to be adsorbed to any iron oxide surfaces under oxic conditions. Uranium and selenium are likely to reprecipitate in anoxic zones. This provides the opportunity for natural treatment within the storage zone to control mobilised trace metal species.

Large areas of prospective North and North-East Queensland have been surveyed by airborne hyperspectral sensor, HyMap, and airborne geophysics as part of the 'Smart' exploration initiative by the Geological Survey of Queensland. In particular, 25000 km2 of hyperspectral mineral and compositional map products, at 4.5 m spatial resolution, have been generated and made available via the internet. In addition, more than 130 ASTER scenes were processed and merged to produce broad scale mapping of mineral groups (Thomas et al, 2008). Province-scale, accurate maps of mineral abundances and minerals chemistries were generated for North Queensland as a result of a 2 year project starting in July 2006 which involved CSIRO Exploration and Mining, the Geological Survey of Queensland (GSQ), Geoscience Australia, James Cook University, and Curtin University. Airborne radiometric data acquired over the same North Queensland Mt Isa - Cloncurry areas as the hyperspectral surveys, had been acquired at flight line spacing of 200 metre. Such geophysical radiometric data provides a useful opportunity to compare the mineral mapping potential of both techniques, for a wide range of geological and vegetated environments. In this study, examples are described of soil mapping within the Tick Hill area, and geological / exploration mapping within the Mt Henry and Suicide Ridge prospects of North Queensland.

New ASTER GIS products in the Gawler-Curnamona Geoscience Australia, in collaboration with CSIRO and PIRSA are releasing a suite of 14 new ASTER mosaiced products for a significant part of the Gawler-Curnamona region. About 110 ASTER scenes have been mosaiced and processed into geoscience products that can be quickly and easily integrated with other datasets in a GIS. The products have been pre-processed and calibrated with available HyMap data and provide basic mineral group information such as Ferric Oxide abundance, AlOH group distribution as well as mosaiced and levelled false colour and regolith ratio images. These images, along with accompany notes are available for free ftp download online at: ftp://ftp.arrc.csiro.au/NGMM/Gawler-Curnamona ASTER Project/

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 area was visited in company with Mr. R.S. Matheson of the Geological Survey of Australia in December, 1942, when eleven pigmatite bodies bearing mica and beryl were examined. The report furnished after that visit (1943/2), gives details of access, topography, climate and vegetation which are not repeated here. In view of the urgent demand in Australia for "strategic" mica, i.e. mica of quality equivalent to Clear and Commercial-clear, it was recommended that one deposit at Yinnietharra should be opened and prospecting of others carried on simultaneously. As a result of these recommendations, the Deputy Controller of Mineral Production started mining operations on the selected dyke by open-cutting in June, 1943. Although it was stressed in the abovementioned report that poor exposure of the dyke, on which there were no workings, rendered any estimate of the probable yield of marketable mica speculative, the results actually obtained were far below expectations, and a heavy financial loss on the project was incurred. Consequently, while the question of abandoning the mine was under consideration, a detailed examination of the workings was carried out in June, 1944, again in the company of Mr. Matheson, and the results of this investigation, which was not wholly confined to geological aspects, are embodied in the present report.

Report on the method and findings of the beach sands investigation in the area between ML180 and DC22, Broadbeach to North Burleigh. Estimates of the quantities and grades of heavy mineral concentrates, the quantities of overburden, and the quantities of each of the heavy minerals are tabulated.

Regolith materials spatially and chemically associated with various types of ore deposits, such as iron oxides, manganese oxides and gold deposits for example, have the potential to be mapped and characterised using remote sensing techniques. With the release of new state-scale multispectral data such as the Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) Geoscience map of Western Australia (Figure 1), these applications may be tested and evaluated, along with identifying ore deposit types and characteristics best suited to using remote sensing techniques. A world-first continental scale ASTER mosaic and pre-competitive geoscience products for Australia are planned for public release in August 2012. The ASTER products are designed to provide broad scale mineral group information for mineral explorers at the continental to prospect scale. The product will be particularly useful for obtaining information on remote or difficult to access areas of Australia. ASTER data consists of 14 bands from Visible and Near Infrared (VNIR) light, through Short Wave Infrared (SWIR) and Thermal Infrared (TIR) encompassing different reflectance and emission spectras from the top few microns of material on the Earth's surface (Figure 2).

Legacy product - no abstract available