An integrated analysis of both airborne and field short-wave infrared hyperspectral measurements was used in conjunction with conventional field mapping techniques to map hydrothermal alteration in the central portion of the Mount Painter Inlier in the Flinders Ranges, South Australia. The airborne hyperspectral data show the spatial distribution of spectrally distinct minerals occurring as primary minerals and as weathering and alteration products. Field spectral measurements, taken with a portable infrared mineral analyzer spectrometer and supported by thin-section analyses, were used to verify the mineral maps and enhance the level of information obtainable from the airborne data. Hydrothermal alteration zones were identified and mapped separately from the background weathering signals. A main zone of alteration, coinciding with the Paralana Fault zone, was recognized, and found to contain kaolinite, muscovite, biotite, and K-feldspar. A small spectral variation associated with a ring-like feature around Mount Painter was tentatively determined to be halloysite and interpreted to represent a separate hydrothermal fluid and fluid source, and probably a separate system. The older parts of the alteration system are tentatively dated as Permo-Carboniferous. The remote sensing of alteration at Mount Painter confirms that hyperspectral imaging techniques can produce accurate mineralogical maps with significant details that can be used to identify and map hydrothermal activity. Application of hyperspectral surveys such as that conducted at Mount Painter would be likely to provide similar detail about putative hydrothermal deposits on Mars.

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

The Archean Pilbara granitoid-greenstone terrane (GGT) has been the focus of numerous studies on Archaean geology, especially the classic dome-and-basin area around Marble Bar in the east Pilbara. This area has been used as evidence for different tectonic processes, i.e. that vertical tectonics or diapirism was a cause for Archean deformation. This paper provides evidence to support regional horizontal (plate-interaction) stresses as being largely responsible for the compressive deformation of the Pilbara GGT, at least from ca. 3.2 Ga. The relative chronology of meso-to macro-scale structural elements are presented for a number of selected areas across the Pilbara GGT. These locally identified events are correlated with a regional (Pilbara-wide) structural framework of deformation events that are constrained by geochronological and stratigraphic controls. The dome-and-basin geometry characteristic of the east Pilbara was established after 3.2 Ga, and was successively modified by repeated orthogonal extensional and compressive (subhorizontal) events. The result has been a locally complex development of polyphase structural elements with consistent overprinting relationships that can be correlated across much of the Pilbara from 3.2 Ga. Diapirism did not cause these deformation elements, although it may have modified them.

These data represent the OZCHRON database of physical age determinations of Australian rocks, and the radiogenic isotope ratios used in determining the ages. OZCHRON datasets comprise bibliographic references, analytical data and pooled results for samples derived using the Rb-Sr, SHRIMP, U-Pb, and Sm-Nd age determination methods.

Mineralizing events in the North Pilbara terrain of Western Australia occurred between 3490 and 2700 Ma and include the oldest examples in the world of many ore deposit types. These events were pulsed and associated with major volcano-plutonic episodes (volcanic-hosted massive sulfide, porphyry Cu, Sn-Ta pegmatite, mafic-ultramafic-hosted Ni-Cu-PGE, and epithermal deposits) and deformation events (lode Au deposits). In many cases, the mineralizing events are associated with extension, either in rifts, pull-apart or back-arc basins, or as the consequence of doming associated with granitoid diapirism. Although mineralizing events occurred throughout the evolution of the North Pilbara terrain, the largest deposits are related to the development of the Mallina basin, which is located between the older East and West Pilbara granite-greenstone terranes. Four volcano-plutonic and three deformation events occurred in and around the Mallina basin between 2950 and 2840 Ma. Mineralization in the East and West Pilbara granite-greenstone terranes is less intense and occurred over a much longer period. Compared to other Archean granite-greenstone terrains, the North Pilbara terrain is poorly endowed; the only known world-class deposit in this region is the Wodgina Ta-Sn pegmatite deposit, but large iron ore deposits are being mined in the northeastern North Pilbara terrain. The long history of crustal development and slow rate of crustal growth may be responsible for the diversity of mineral deposits and could account for the apparent poor endowment of the North Pilbara terrain.

The Diverse Structure of Archean Lode Gold Deposits of the Southwest Mosquito Creek Belt, East Pilbara Craton, Western Australia

In the Eastern Lachlan Orogen, the mineralised Molong and Junee-Narromine Volcanic Belts are two structural belts that once formed part of the Ordovician Macquarie Arc, but are now separated by younger Silurian-Devonian strata as well as by Ordovician quartz-rich turbidites. Interpretation of deep seismic reflection and refraction data across and along these belts provides answers to some of the key questions in understanding the evolution of the Eastern Lachlan Orogen-the relationship between coeval Ordovician volcanics and quartz-rich turbidites, and the relationship between separate belts of Ordovician volcanics and the intervening strata. In particular, the data provide evidence for major thrust juxtaposition of the arc rocks and Ordovician quartz-rich turbidites, with Wagga Belt rocks thrust eastward over the arc rocks of the Junee-Narromine Volcanic Belt, and the Adaminaby Group thrust north over arc rocks in the southern part of the Molong Volcanic Belt. The seismic data also provide evidence for regional contraction, especially for crustal-scale deformation in the western part of the Junee-Narromine Volcanic Belt. The data further suggest that this belt and the Ordovician quartz-rich turbidites to the east (Kirribilli Formation) were together thrust over Cambrian-Ordovician rocks of the Jindalee Group and associated rocks along west-dipping inferred faults that belong to a set that characterises the middle crust of the Eastern Lachlan Orogen. The Macquarie Arc was subsequently rifted apart in the Silurian-Devonian, with Ordovician volcanics preserved under the younger troughs and shelves (e.g. Hill End Trough). The Molong Volcanic Belt, in particular, was reworked by major down-to-the-east normal faults that were thrust-reactivated with younger-on-older geometries in the late Early - Middle Devonian and again in the Carboniferous.

No abstract available

Legacy product - no abstract available