The national mineral deposits dataset covers 60 commodities and more than 1050 of Australia's most significant mineral deposits - current and historic mines and undeveloped deposits. Subsets can also be created based on any attribute in the database (e.g. commodity, geological region, state/territory).

Biostratigraphy is the branch of stratigraphy that uses fossils to establish relative ages of rock and correlate successions of sedimentary rocks within and between depositional basins. A biozone is an interval of geologic strata characterised by certain fossil taxa. Such intervals are often defined by the first appearances (range bases), apparent extinctions (range tops/last appearances), or abundances of fossil index species. These key index species should be relatively abundant, short-lived taxa that are easy to recognise and as geographically widespread as possible. Widely used fossil groups include brachiopods, conodonts, dinoflagellate cysts, foraminifera, graptolites, nannofossil, spores and pollen and trilobites. Zonal schemes based on several different fossil groups can be used in parallel, and the zones can be calibrated to the absolute geological timescale using tie points to rocks which have been radio-isotopically dated.

These data are a digital representation of information depicted on the printed maps of Seigal, Hedleys Creek, Carrara Range Region, Lawn Hill Region, Riversleigh, Constance Range Region, Mount Oxide Region, Mammoth Mines Region, Myally, Alsace, Coolullah, Kennedy Gap, Prospector, Quamby, Mount Isa, Mary Kathleen, Marraba, Cloncurry, Oban, Duchess Region, Malbon, Kuridala Region, Selwyn Region, Dajarra and Ardmore 1:100 000 Geological Series and Mount Drummond 1:250 000 Geological Series produced by AGSO, the Geological Survey of Queensland (GSQ) and Northern Territory Geological Survey (NTGS). Data present include geological polygons (litho-stratigraphic units), linear structural features (faults, dykes, folds, trends, lineaments etc), and point features (mines, structural points etc). Polygons have a range of attributes extracted from each individual map including unit name, era, period and lithological description, while lines and points are feature coded according to the AGSO publication 'Symbols Used On Geological Maps' (BMR 1989). A standard look-up table of AGSO geological codes and associated descriptions is available (see ADDITIONAL METADATA). The data has gradually evolved from elementary CAD quality data into its present topologically structured GIS format, and hence has many imperfections and inconsistencies. Data has undergone rigorous validation and testing that includes over 80 different tests.

part-page item on matters related to stratigraphy. This column discusses a definition of the 'year' and the use of Beds vs beds in describing Australian lithostratgraphic units. Journal ISSN 0312 4711

Geoscience Australia has released two web-based map sheets (GeoCat 69347) that show the continental extent and age relationships of Archean mafic and ultramafic rocks and associated mineral deposits throughout Australia. Geoscience Australia Record 2009/41 is a user guide which compiles all the geological and geochronological data that underpins the information portrayed on these two new map sheets. The Archean eon (~4000 million years to 2500 million years) represents an early part of Earth's history that is noteworthy for the occurrence of unusual olivine-rich ultramafic rocks called komatiites which contain world-class deposits of nickel sulphides. Archean mafic and ultramafic igneous rocks with reliable crystallisation ages in Australia are confined to the older crustal components in Western Australia and South Australia. In this study, twenty-six Archean Magmatic Events (AME) ranging in age from the Eoarchean ~3730 Ma (AME 1) to the late Neoarchean ~2520 Ma (AME 26) were identified. This mafic-ultramafic magmatic event series is based on several hundred published age measurements, of which over 95 per cent are derived from recent Uranium-Lead dating of zircon and baddeleyite. The new map sheets, when used in association with the `Australian Proterozoic Mafic-Ultramafic Magmatic Events' map published in 2008 (GeoCat 66114; GA Record 2008/15: GeoCat 66624), summarise the temporal and spatial evolution of Precambrian mafic-ultramafic magmatism in Australia. These maps provide a national framework for investigating under-explored and potentially mineralised environments, and assessing the role of mafic-ultramafic magmatism in the development of the Australian continent. The maps will be of interest to explorers searching for nickel, platinum-group elements, chromium, titanium, vanadium, and cobalt.

This record contains descriptions, interpretations and all of the measured sections and drillholes logged during the NABRE project research between 1995 and 1998. New subdivisions of the successions and correlations with similar aged rocks in the Lawn Hill and Mt Isa regions are presented.

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Quarterly column on issues in Australian stratigraphy