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  • The Glenloth Granite is an icon of South Australian geology, having been the site of some of the earliest gold workings in the central portion of what is now known as the Gawler Craton and the subject of some of the first radiometric age determinations in the 1960's. The Glenloth Granite forms part of the Neoarchaean to earliest Palaeoproterozoic belt of supracrustals and associated intrusives known as the Mulgathing Complex, which includes mafic to ultramafic (komatiitic) volcanics. Inferred to be syn-tectonic in nature in the original 1:250 000 scale mapping of the region, new SHRIMP data shows that the Glenloth Granite was emplaced at 2508 +/- 2 Ma, during period of magmatism that predates the ca. 2470 - 2420 Ma Sleafordian Orogeny. This orogenic event reworked the Glenloth Granite in to magmatitic gneiss and is responsible for two main generations of metamorphic zircon growth at 2453 +/- 4 Ma and 2427 +/- 3 Ma, likely reflecting initial prograde metamorphism followed by migmatite formation during biotite dehydration reactions, as has been documented from elsewhere in the Mulgathing Complex.

  • Detrital zircon from sandstone bodies intersected in three recent exploration wells on the North West Shelf were analysed and dated using the SHRIMP (Sensitive High Resolution Ion Microprobe) at Geoscience Australia to test the technique as a tool for understanding the provenance and sediment transport pathways of reservoir facies in the region. Chevron, Hess and Santos, the operating companies for exploration permits WA- 365-P, WA-390-P and WA-281-P respectively, collected 3-5 kg of cuttings from the wells Guardian-1 and Hijinx-1 (Triassic Mungaroo Formation on the Exmouth Plateau of the Carnarvon Basin) and Burnside-1 (Jurassic Brewster Sands from the Browse Basin). All three wells were drilled in 2009-2010. Samples were prepared at Geoscience Australia with 70-80 zircon grains randomly selected for analysis following standard data acquisition and processing procedures to provide a statistically meaningful representation of detrital ages in each sample.

  • Speculation is increasing that Proterozoic eastern Australia and western Laurentia represent conjugate rift margins formed during breakup of the NUNA supercontinent and thus share a common history of rift-related basin formation and magmatism. In Australia, this history is preserved within three stacked superbasins formed over 200 Myr in the Mount Isa region (1800-1750 Ma Leichhardt, 1730-1670 Ma Calvert and 1670-1575 Ma Isa), elements of which extend as far east as Georgetown. The Mount Isa basins developed on crystalline basement of comparable (~1840 Ma) age to that underlying the Paleoproterozoic Wernecke Supergroup and Hornby Bay Basin in NW Canada which share a similar tripartite sequence stratigraphy. Sedimentation in both regions was accompanied by magmatism at 1710 Ma, further supporting the notion of a common history. Basin formation in NW Canada and Mount Isa both concluded with contractional orogenesis at ~1600 Ma. Basins along the eastern edge of Proterozoic Australia are characterised by a major influx of sediment derived from juvenile volcanic rocks at ~1655 Ma and a significant Archean input, as indicated by Nd isotopic and detrital zircon data. A source for both these modes is currently not known in Australia although similar detrital zircon populations are documented in the Hornby Bay Basin, and in the Wernecke Supergroup, and juvenile 1660-1620 Ma volcanism occurs within Hornby Bay basin NW Canada. These new data are most consistent with a northern SWEAT-like tectonic reconstruction in a NUNA assembly thus giving an important constraint on continental reconstructions that predate Rodinia.

  • The Mount Painter Province is located in the northern Flinders Ranges, South Australia and comprises deformed Proterozoic metasedimentary and igneous rocks.

  • Devonian-Carboniferous granites are widespread in Tasmania. In the east they intrude the Ordovician-Early Devonian quartzwacke turbidites of the Mathinna Supergroup, whereas the western Tasmanian granites intrude a more diverse terrane of predominantly shelf sequences, with depositional ages extending probably back to the Late Mesoproterozoic. The earliest (~400 Ma) I-type granodiorites in the east may be arc-related and pre-date the Tabberabberan Orogeny (~388 Ma), which appears to represent the juxtaposition of the two terranes. Subsequently more felsic and finally strongly fractionated I- and S-type granites were emplaced until ~373 Ma. In western Tasmania, mostly felsic and fractionated I- and S-types granites were emplaced from ~374-351 Ma, possibly in response to back-arc or post-collisional crustal extension

  • This work forms part of a major internation multi-disciplinary study of the Permian -Triassic boundary, end-Permian mass extinction and Middle Permian-Early Triassic timescale calibration. Studies undertaken in the overarching program include biostratigraphy, isotope geochronology, magnetostratigraphy, and chemostratigraphy.

  • New and existing Sm-Nd whole rock isotope data and U-Pb zircon ages from sedimentary rocks in several Australian Proterozoic Provinces hosting Zn-Pb mineralisation show a distinct transition that corresponds to a change from evolved sediment sources to more juvenile sedimentary sources at ~1650 Ma. This Sm-Nd isotopic change has been documented in the Eastern and Western Successions of the Mount Isa Inlier, the Etheridge Province of the Georgetown Inlier. A similar transition at ~1650 Ma has also been documented in the Broken Hill and Olary Domains of the Curnamona Province (Barovich and Hand 2008) and defines a continental-scale isotopic signal. The world-class, sediment-hosted Mt Isa and Hilton-George Fisher Zn-Pb Mt Isa-style deposits in the Western Mount Isa Inlier occur above the transition in sediments derived from more juvenile sources. In contrast, Pb-Zn-Ag Broken Hill-style deposits, including the Broken Hill (Curnamona), Cannington (Isa), Mount Misery (now Chloe) and Railway Flat deposits (Georgetown Inlier) (Carr et al. 2004) occur below this ~1650 Ma transition in sediments which have a much more evolved source.

  • This Record presents new zircon U-Pb geochronological data, obtained using a Sensitive High Resolution Ion MicroProbe (SHRIMP) for thirty-five samples of plutonic rocks from the New England Orogen, New South Wales. The work was carried out under the auspices of the National Geoscience Accord, as a component of the collaborative Geochronology Project between the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA) during the reporting periods 2012-2014.

  • New SHRIMP U-Pb zircon ages from the New England Orogen, New South Wales July 2014-June 2015

  • This Record presents new zircon U-Pb geochronological data, obtained using a Sensitive High Resolution Ion MicroProbe (SHRIMP), and thin section descriptions for four samples of plutonic and sedimentary rocks from the Captains Flat 1:50, 000 special map sheet, Eastern Lachlan Orogen, New South Wales. The work was carried out under the auspices of the National Geoscience Accord, as a component of the collaborative Geochronology Project between the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA) during the reporting periods 2012 and 2013. The four samples (Table 1.1 and Figure 1.1) were collected from CANBERRA (small and large capitals refer to map sheet names in the 1:100 000 and 1:250 000 Topographic Series respectively); one sample from CANBERRA (northcentral CANBERRA), two from MICHELAGO (southcentral CANBERRA) and one from ARALUEN (southcentral CANBERRA).