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.

A 2-D crustal velocity model has been derived from a 1997 364 km north-south wide-angle seismic profile that passed from Ordovician volcanic and volcaniclastic rocks (Molong Volcanic Belt of the Macquarie Arc) in the north, across the Lachlan Transverse Zone into Ordovician turbidites and Early Devonian intrusive granitoids in the south. The Lachlan Transverse Zone is a proposed west-northwest to east-southeast structural feature in the Eastern Lachlan Orogen and is considered to be a possible early lithospheric feature controlling structural evolution in eastern Australia; its true nature, however, is still contentious. The velocity model highlights significant north to south lateral variations in subsurface crustal architecture in the upper and middle crust. In particular, a higher P-wave velocity (6.24-6.32 km/s) layer identified as metamorphosed arc rocks (sensu lato) in the upper crust under the arc at 5-15 km depth is juxtaposed against Ordovician craton-derived turbidites by an inferred south-dipping fault that marks the southern boundary of the Lachlan Transverse Zone. Near-surface P-wave velocities in the Lachlan Transverse Zone are markedly less than those along other parts of the profile and some of these may be attributed to mid-Miocene volcanic centres. In the middle and lower crust there are poorly defined velocity features that we infer to be related to the Lachlan Transverse Zone. The Moho depth increases from 37 km in the north to 47 km in the south, above an underlying upper mantle with a P-wave velocity of 8.19 km/s. Comparison with velocity layers in the Proterozoic Broken Hill Block supports the inferred presence of Cambrian oceanic mafic volcanics (or an accreted mafic volcanic terrane) as substrate to this part of the Eastern Lachlan Orogen. Overall, the seismic data indicate significant differences in crustal architecture between the northern and southern parts of the profile. The crustal-scale P-wave velocity differences are attributed to the different early crustal evolution processes north and south of the Lachlan Transverse Zone.

ACRES Update Monitoring pastures from space Remote sensing research at Coleambally Irrigation Area Satellite imagery helps to classify Australia's estuaries

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.

This black and white 64 page education resource examines the dynamic nature of Earth's climate (past and present) and its many influencing factors. Includes student activities. Suitable for secondary Years 7-12.

The digital dataset combines data from the Oracle ozchron, sites, and rocks tables and is presented as shapefiles and mapinfo files for the rubidium-strontium, conventional uranium-lead and samarium-neodymium geochronology themes. This dataset package will eventually include the uranium-lead shrimp data, and is intended to be updated on a regular basis until the project is completed.

The Archaean granite-greenstones in the SIR SAMUEL 1:250 000 sheet area can be divided into three north- to north-northwest-trending strips of greenstones that are separated by large areas of granitoid. The west strip varies in width from 2 to 17 km, and includes the Perseverance-Mount Keith, Agnew, and Yakabindie greenstone belts. The far west part of the sheet is largely granitoid, with an arcuate belt up to 18 km wide of highly deformed and gneissic granitoid west of the Waroonga Shear Zone. The southern Yandal greenstone belt is separated from the Perseverance-Mount Keith greenstone belt by a large area of granitoid, including the sigmoidal Koonoonooka monzogranite, and a highly deformed zone, up to 12 km wide, of interleaved granitoid and greenstone west of the Mount McClure Fault. Part of the Dingo Range greenstone belt occurs in the northeast. The Yakabindie greenstone belt comprises a layered sequence of the Kathleen Valley Gabbro overlain by the massive tholeiitic Mount Goode Basalt. The Agnew greenstone belt comprises a lower sequence of metamorphosed ultramafic, mafic, felsic volcanic, and sedimentary rocks, which is exposed in the Lawlers and Leinster Anticlines. The upper sequence, as in the Mount White Syncline area, consists of metabasalt, metagabbro and metasedimentary rocks. Metamorphosed ultramafic, mafic, felsic volcanic and sedimentary rocks in the Perseverance area extend farther north to west of Mount Pasco. From Six Mile Well, ultramafic, sedimentary, and felsic volcanic/volcaniclastic rocks correlate well with the greenstone sequences through Mount Keith to Wiluna. The Jones Creek Conglomerate represents a late clastic sequence and is restricted to a narrow, fault-bounded zone between the Yakabindie greenstone belt and granite in the west and the Perseverance-Mount Keith and Agnew greenstone belts to the east. The southern Yandal greenstone belt consists of two major packages of greenstones, i.e., mafic and som e ultramafic rocks in the Bronzewing - Mount McClure, Hartwell, Yandal Well and Darlot areas, and felsic rocks along the Ockerburry Fault Zone and Spring Well area. In the Dingo Range greenstone belt, the Dingo Range antiform is interpreted to be a refolded earlier fold of banded iron formation/chert, ultramafic and basaltic rocks. In the Mount Harold area some felsic volcanic/volcaniclastic rocks occur. The Stirling Peaks area is largely little deformed fine grained metabasalt. Three major deformation events are recognised in the granite-greenstones in the SIR SAMUEL area. The first deformation, although poorly understood, produced bedding-parallel foliation including flattened pillow structures in basalt, and some tight to isoclinal folds. Major orogenic compression during D2 produced the north-northwest greenstone belt trends and linear structures including faults, shear zone s and folds. During D3, deformation appears to have been largely concentrated along major shear zones. Some north- to north-northeast-trending structures were probably produced, or reoriented into their current positions, during D3, which shaped the current structural architecture. Structures in the southern Yandal greenstone belt are best configured in terms of a compressional jog. Post-D3 deformation is represented by normal faults, fractures, and sub-horizontal crenulations. A major phase of regional metamorphism was initiated during D2 and peaked late during or after D2. Granite intrusion occurred throughout the deformation and metamorphic history in the SIR SAMUEL area. Related products <a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&amp;catno=34433">Associated 1:250,000 scale digital dataset product information</a>

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

During 2000 the Australian Geological Survey Organisation (now Geoscience Australia) operated geomagnetic observatories at Alice Springs and Kakadu in the Northern Territory, Canberra in the Australian Capital Territory, Charters Towers in Queensland, Gnangara and Learmonth in Western Australia, Macquarie Island, Tasmania, in the sub-Antarctic, and Mawson in the Australian Antarctic Territory. Magnetic recording also took place at the stations of Casey and Davis in the Australian Antarctic Territory. This report describes instrumentation and activities, and presents monthly and annual mean magnetic values, plots of hourly mean magnetic values and K indices at the magnetic observatories and repeat stations operated by Geoscience Australia during calendar year 2000.

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