GU Report 15 - Preliminary report: fluid inclusion noble gas and halogen signature of gold deposits in the western Lachlan Fold Belt, central Victoria
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Product description:Abstract Fluid inclusion noble gas and halogen geochemistry has been widely used to quantify the contributions of different reservoirs (e.g., mantle, crust, hydrosphere, atmosphere) to mineralising fluids associated with a diverse range of ore deposits. Although many of the large turbidite-hosted (‘orogenic’) gold deposits from the western Lachlan Fold Belt in central Victoria, are believed to have formed during or shortly after syn-orogenic metamorphism in the Early Paleozoic, a few others are regarded as being ‘intrusion-related’. However, an overview of fluid inclusion data indicates that fluid compositions associated with both deposit types are typically carbonic, low-salinity brines, and are thus indistinguishable. Noble gas and halogen geochemistry of fluid inclusions in quartz separates from selected ‘orogenic’ and ‘intrusion-related’ gold deposits in central Victoria suggests negligible input of ‘juvenile’ mantle-derived components in the mineralising fluids. Instead, all the fluids are interpreted to be of crustal origin and likely related to metamorphic devolatisation of basement rocks. Based on current chemical and isotopic data, it is concluded that the so-called ‘intrusion-related’ gold deposits had similar fluid origins as ‘orogenic’ gold deposits in Victoria. Consequently, the source of gold is most likely to have been the metamorphosed basement sedimentary-volcanic rocks. Download The downloadable version of this report is supplied in PDF format. Bibliographic reference Fu, B., Kendrick, M.A. & Phillips, D. 2009. A preliminary report on the fluid inclusion noble gas and halogen signature of gold deposits in the western Lachlan Fold Belt of central Victoria, Australia. GeoScience Victoria Gold Undercover Report 15. Department of Primary Industries. Related products:
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