mineralogy
Type of resources
Keywords
Publication year
Scale
Topics
-
Mapping and analysis of landscapes in Australia can now benefit from a continental mineral map coverage, helping to identify and characterise materials at the surface, with the recent release (August 2012) of the Satellite ASTER Geoscience Maps of Australia (http://c3dmm.csiro.au/Australia_ASTER/stage_1_geoscienceproductnotes.html). The new maps can provide mineralogical information on weathering, soils and regolith boundaries and compositions. The ASTER mosaic, made up of some ~3,500 60x60 km individual ASTER scenes, were produced by a multi-agency collaboration of Australian government partners. They represent the first of their kind: a continent-scale, public, web-accessible and GIS-compatible ASTER geoscience product suite. Led by CSIRO, Geoscience Australia along with several state government agencies, (including GSWA, GSQ, DMITRE and NTGS), have released 17 geoscientific products across the whole of Australia, with application to landscape analysis, environmental studies, mineral mapping and exploration, as well as soil-mapping and the agricultural sectors. Outcomes have included the formation of a platform for establishing national standards, geoscience product nomenclature, processing methods, accuracy assessments and traceable documentation. The ASTER bands are being used together with other complementary datasets (e.g. terrain indices, gamma-ray radiometrics) to build statistical predictive models on surface regolith geochemistry. This study is a preliminary investigation and assessment of how to use the new products for geomorphic applications, particularly landscape analysis and characterisation.
-
An outcrop of marmatite (zinc sulphide) has been located within the boundaries of E.P.L.26 held by New Guinea Goldfields Limited. The following notes describe the outcrop as discovered and certain recommendations are made to assist in the evaluation of the outcrop as a base-metal orebody. Other recommendations are made embracing other known occurrences of base-metal sulphides in the Territory of Papua and New Guinea.
-
An examination was made of many of the mines in the Harts Range and Plenty River mica fields during the latter portion of 1951, in the company of Messrs. G.F. Joklik and W. Roberts. The work involved mine surveying and mapping. A great deal of information of a general nature was obtained from Mr. Joklik, who has spent much time studying the regional geology of the area and the mica deposits. The observations here recorded in regard to mining are the writer's responsibility. The geology of the deposits, mining, and exploration, are discussed.
-
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.
-
Two million alluvial macrodiamonds recovered from Tertiary deep leads in the Copeton/Bingara (C/B) area of New England (NSW) formed by ultrahigh pressure metamorphism during Phanerozoic subduction - based on unique isotopic composition (?13C>0), unique inclusions and high pressures on inclusions. The techniques used were either destructive or only succeeded on 3% of 200 stones tested with inclusions. Some researchers have suggested that UHP microdiamond (e.g. from Kochetav) lacks the 2nd order Raman spectral pattern (2200-2700cm-1) that is prominent in cratonic diamond. Our work on African cratonic macrodiamond shows this peak is suppressed if the stone is UV fluorescent, but is strong at 15-75× (signal to noise ratio S/N) for a low background (?1100 counts per second). For NSW macrodiamond with a low background, this peak is greatly reduced at 2-14× S/N for C/B (45 stones), Mt Airly (4), Walcha (2), Frenchmans (1 ) and Wenona Diatreme (1), calibrating the test. This new combined technique (UV lamp, 2nd order Raman) is much faster and works on a larger fraction of stones (including those without inclusions; 13% of C/B stones are low background). Strong brittle/plastic deformation during growth of C/B diamond is confirmed by growth textures and Laue Xray photography, indicating growth during subduction - promoting strong nitrogen aggregation, and suppressing the 2nd order Raman spectral signal. This Raman test should apply to all subduction diamond, including superdeep diamond.
-
Using geophysical-geochemical spatial data to map of hydrothermal footprints in the Eastern Fold Belt of the Mount Isa Inlier
-
In 1946 and 1947 the writer had excellent opportunities to study the effect of lateritisation in the course of geological reconnaissances in Northern Australia. From field evidence which has been collected on several aspects of lateritisation - origin, products and relationship to geomorphological processes - a detailed account of lateritisation in Australia can be given. Lateritisation and the occurrence of opal are discussed in this report.
-
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.
-
Legacy product - no abstract available
-
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.