Geochemical exploration using acid insoluble residues of rocks for volcanic-hosted massive sulphide deposits, Rosebery area, western Tasmania

摘要: Abstract The Rosebery deposit is one of the major massive sulphide deposits in Mount Read Volcanic belt western Tasmania. 200×20 km Volcanics, which world's richest provinces volcanic-hosted (VHMS) deposits, hosts more than 40 mineral occurrences including at Lyell, Hercules, Rosebery, Que River and Hellyer. In this study, hot HNO3 insoluble residues rocks were used to define geochemical halos associated with VHMS identify alteration related mineralisation. after acid treatment are composed mainly quartz, mica feldspar (plagioclase K-feldspar) traces chlorite kaolinite some samples. Quartz, sericite, chlorite, carbonate, etc., principal products relate both mineralisation metamorphism deformation region. There no significant differences between unrelated mineralogical alteration. two types area. type-1 halo trends NE–SW, wall-rock alteration, defined by enrichment Cl, possibly K Rb, depletion Al, Ca, Na, Ti Sr. It passes discordantly from west east across White Spur Formation, altered footwall, host rock deposit, hanging wall Black Volcanics. type-2 halo, trending N–S (largely stratabound), characterised Fe, Mn, Ba, Zn, Pb K, Rb F. outlines mineralised footwall zone, also extends toward south into unaltered rocks. Both intersect zones Recognition has led formulation indices for identification Binary relations (Mn × Ba F) (Ca Na Sr), Ba) (Na their ratios F)/(Ca Sr) Ba)/(Na distinguish it These other all display similar signatures. can be distinguished higher values (K Mn Rb), Ba).