Base metall deposits, Rum Jungle, N.T., Australia

Research project P 14293 Base metal deposits, Rum Jungle, N.T., Australia Eugen F. STUMPFL 06.03.2000 Most of the world`s major base metal deposits (Mt. Isa, Iberian Pyrite Belt, McArthur River, Ireland, etc.) have, in recent years been the subject of comprehensive geoscientific investigations. One of the few exceptions is the Rum Jungle area in the Pine Greek Orogen of Northern Australia, where significant Cu-Pb-Zn-Co-Ni-Ag mineralisation occurs in metamorphosed Proterozoic sediments, partly stratabound and partly in structural settings. The presence of Ni and Co distinguish these deposits from similar base metal occurences world-wide. Attempts at dating the mineralising events have, so far, failed to provide conclusive evidence. Published ages range from 1.8 to 0.5 Ga. Magnesite and phosphate deposits occur in the vicinity of the base metal deposits, three of which form the core of the proposed investigations. These are Whites and Woodcutters, which have been mined out and Browns, which is presently being explored. We thus have a unique situation: ore mineralisation in stratabound and structural settings, unusual element combinations, variation from Co + Cu to Pb + Co across orebodies, widespread magnesite, unclear results of age determination and a major regional lineament, the Giants Reef Fault. From the logistical point of view there are new exploration activities and the decided interest of the Northern Territory Geological Survey (NTGS) in cooperation with the applicants. We therefore propose to conduct a comprehensive geoscientific investigation of the Rum Jungle base metal mineralisation focussing on the Whites, Browns and Woodcutters deposits. This will include study and evaluation of the extensive NTGS data bases and drill core libraries, field work, microscopy in transmitted and reflected light, microprobe and stable isotope studies. Special emphasis will be placed on fluid inclusions, utilizing the extensive facilities now available at Leoben. These include geothermometry, laser Raman spectroscopy, FTIR spectroscopy and laser ablation ICP-MS. The aim of the project is to determine, within the stratigraphic and structural context, the fluid evolution and the metal sources, which led to this unusual type of mineralisation. This will form the basis for a genetic interpretation of the Rum Jungle ores. It will also address the question whether these deposits can be considered part of what has loosely been termed the North-East Australian Zinc Belt or whether they represent a separate, genetically independent ore province. Finally, it is considered relevant to maintain and expand, by projects such as this, European know-how in mineral deposits geology. This has been severely endangered and curtailed by the decline of mining and exploration activities in Europe. Association with the European Science Foundation mineral deposit initiative, GEODE, is planned.