Zircons within the Eocence Garford Paleochannel, central South Australia, were derived from two main sources: (1) local Archean-Mesoproterozoic rocks of the Gawler Craton exposed within the paleocatchment, including the 2525-2440 Ma Mulgathing Complex and 1595-1575 Ma Gawler Range Volcanics-Hiltaba Suite, and (2) Phanerozoic sedimentary rocks within the catchment that contribute a late Mesoproterozoic to Cretaceous component of recycled zircons from a variety of primary sources. These sources include the 1190-1120 Ma Pitjantjatjara Supersuite and 1080-1040 Ma Giles Complex, within the Musgrave Province; c. 510 Ma syn-Delamerian magmatism possibly derived from the Adelaide Rift Complex; and Jurassic-Cretaceous zircons ranging from ~220 Ma to ~100 Ma, with one statistical population at 122 ± 3 Ma. It is likely that zircons from these sources outside the paleocatchment were transported into the Mesozoic rocks of the Eromanga Basin within the catchments, before being re-eroded into the Garford Paleochannel. Given the presence of significant gold mineralization within the Neoarchean rocks of the Gawler Craton, the abundance of locally-derived Archean zircons may support the potential for paleoplacer gold deposits within the Eocene paleodrainage system. Likewise, the abundance of zircons derived from the Gawler Range Volcanics/Hiltaba Suite may support the notion that potential secondary uranium mineralisation within the paleochannels may have a source in these commonly uranium-enriched Mesoproterozoic volcanics and granites. Finally, these data suggest that the Garford Paleochannel was not a major contributor to the zircon budget of the paleo-beach heavy mineral sands province of the adjacent Eucla Basin.

Geochronology is the vital fourth dimension for geological knowledge. It provides the temporal framework for understanding and modelling geological processes and rates of change. Incorporating geochronological 'observations and measurements' into interoperable geological data systems is thus a critical pursuit. - Although there are several resources for storing and accessing geochronological data, there is no standard format for exchanging such data among users. Current systems are a mixture of comma-delimited text files, Excel spreadsheets and PDFs that assume prior specialist knowledge and frequently force the user to laboriously - and potentially erroneously - extract the required data manually. - Geoscience Australia and partners are developing a standard data exchange format for geochronological data ('geochronML') within the broader framework of Observations and Measurements and GeoSciML that are an important facet of emerging international geoscience data format standards. - Geochronology analytical processes and resulting data present some challenging issues as a rock "age" is typically not a direct measurement, but rather the interpretation of a statistical amalgam of several measurements chosen with the aid of prior geological knowledge and analytical metadata. The level at which these data need to be exposed to a user varies greatly, even to the same user over the course of a project. GeochronML is also attempting to provide a generic pattern that will support as wide as range of radioisotopic systems as possible. This presentation will discuss developments at Geoscience Australia and the opportunities for collaboration.

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

The Northern Australian Project online GIS, which has been chiefly designed to highlight the results of geochronological research within the project area, was first published in 2003 and updated in July 2004. GIS data reference layers include 1: 250,000, 1: 1 million, and 1: 2,500,000 geological data, regional geophysical images and a topographic map image. The geochronology and fluid inclusion points have been linked live to Geoscience Australia's OZROCKS, OZCHRON and PETROG Oracle databases. Forms display data to the user from these databases using customised query statements. Queries directed to geological layers display information derived from static ArcInfo shapefiles. The North Australia Project geochronology research has chiefly targeted the Arunta Block, Davenport Geosyncline, and the Granites-Tanami Block provinces within the project area.

Field too small

Abstract: The multiply-deformed (D1-D3) Palaeoproterozoic Willyama Supergroup in south-central Australia incorporates upper and lower ca. 1700 Ma metasedimentary sequences with contrasting early tectonothermal histories that invite comparisons with the metamorphic core complexes and younger extensional orogens of western North America and Europe. A detachment surface of D1 age separating these two sequences has the deduced geometry of an extensional shear zone, juxtaposing rocks subjected to bimodal magmatism, sillimanite to granulite grade migmatisation, and Na-Fe metasomatism against a less intensely metamorphosed upper plate lacking both migmatites and bimodal magmatism. Syn-extensional metamorphism took place under low pressure-high temperature conditions, producing regionally extensive andalusite- and sillimanite-bearing mineral assemblages before further high grade metamorphism accompanying D2 recumbent folding and crustal thickening. D2 folding locally inverted the original D1 thermal structure so that sillimanite-grade lower plate rocks now lie structurally above andalusite-grade rocks of the upper plate, rendering recognition of the original detachment surface and associated thermal structure difficult. U/Pb dating of synextensional metabasites intruded into lower plate rocks just below the detachment surface indicate that extension and related bimodal magmatism peaked around 1690-1670 Ma. This is 70-90 m.y. earlier than some previously published 1600-1590 Ma ages for the onset of regional deformation and related low P-high T metamorphism and which we equate with events that overprinted the first phase of deformation and metamorphism at 1690-1670 Ma. A regionally extensive redox boundary associated with the detachment surface served as the locus for fluid flow and Pb-Zn mineralisation.

The 1:100,000 series of maps for Palaeoproterozoic rocks of the Leichhardt River Fault Trough and Lawn Hill Platform of northern Australia arguably form the best set of regional geological maps in the country. Since their release in the 1970?s and early 1980?s they have been extensively used in mineral exploration programs in the Mount Isa Inlier. In this region one of the most obvious lithostratigraphic correlations is based on the assumed equivalence of two sandstone bodies, 1) the Torpedo Creek Quartzite and 2) the Warrina Park Quartzite. Each sandbody forms the basal lithostratigraphic unit of its respective Group (McNamara and Mount Isa) and outcrops as prominent ridges of white quartzite, readily traceable on aerial photographs. The distinctive outcrop character, map patterns and defined stratigraphic relationships have resulted in this correlation forming the `linch-pin? of lithostratigraphic subdivision in the region. Sequence stratigraphic analysis of the Warrina Park and Torpedo Creek Quartzites, the underlying Surprise Creek Formation and overlying fine-grained transgressive siliciclastics has identified a series of chronostratigraphically significant surfaces (sequence boundaries, transgressive surfaces and maximum flooding surfaces) that collectively demonstrate major miscorrelations in the current lithostratigraphic subdivisions. The study demonstrates the potential for major errors associated with lithostratigraphic subdivisions based on the assumed equivalence and continuity of sandbodies. In the case of the Mt Isa region the miscorrelations have resulted in major unconformities with up to 20 my of missing rock record remaining unrecognised in many areas. The consequences of such miscorrelations are inadequate and inaccurate reconstructions of basin geometry, stratigraphic architecture and the mis-identification of synsedimentary growth faults. Because these reconstructions form the essential prerequisites for predictive mineral system models, aimed at constraining the evolution and flow of metal-bearing fluids through these sediments, these inadequacies are of fundamental importance to the exploration industry. This scenario is well recognised in the petroleum industry, where significant effort is made to correctly understand sandbody geometry particularly in reservoir settings where continuity is critical to production and reservoir engineering. The paper provides an example of sandbody miscorrelations in the Palaeoproterozoic successions of northern Australia. Issues raised in this paper are of major significance to the mineral exploration industry as well as state geological surveys and universities involved in mapping programs and basin reconstructions.

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