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This address was presented at the 2009 Australian Nickel Conference held in Perth, 14-15th October 2009. Geoscience Australia has recently released two web-based map sheets (at: http://www.ga.gov.au/resources/maps/minerals/index.jsp) that show the continental extent and age relationships of Archean mafic and ultramafic rocks and associated mineral deposits throughout Australia. The maps were produced in close collaboration with the State and Northern Territory geological surveys. The Archean eon (~4000 million years to 2500 million years) represents an early part of Earth's history that is noteworthy for the earliest forms of life and the widespread occurrence of unusual olivine-rich ultramafic rocks called komatiites which contain world-class deposits of nickel sulphides. The major objective of this presentation is to promote the applications of the National map, which should be of interest to those explorers searching for nickel, platinum-group elements (PGEs), chromium, titanium, and vanadium. 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), 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.

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The Mellish Rise lies off northeast Australia, trends northeast overall, and is about 700 km long and 300 km wide. Much of it lies in Australian territory. In the southwest, near Mellish Reef, a large area is shallower than 2500 m, but further northeast there are only occasional comparably shallow highs. To the northwest the Coral Sea Basin and the Louisiade Trough, and to the southeast the narrow South Rennell Trough and the west D'Entrecasteaux Basin are all deeper than 3500 m. The rise also lies to the north of another fragment of continental crust, the Kenn Plateau. The Mellish Rise and Kenn Plateau have been the subject of recent geoscience surveys of R.V. Southern Surveyor, undertaken by Geoscience Australia, to determine their composition. The emphasis in this report is on the Mellish Rise survey (SS02/2005), during which 1189 km of multichannel seismic data were acquired using a 24 channel, 600 m long streamer and two GI airguns. In addition, multibeam and single beam bathymetry, and magnetic data were recorded. Forty-four dredge sites and five core stations were occupied to investigate the geology, and the great bulk of these deployments were successful. Dredge sites were concentrated on the Mellish Rise and Kenn Plateau, but are also included the Louisiade Plateau. Foraminiferal, nannofossil and petrological studies have been carried out on suitable rocks and sediments.

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Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available