摘要:
The Hongshan-Hongniu super-large skarn copper deposit is located in the southern Zhongdian island arc.In this paper,to decipher the ore-forming fluid source and ore-forming material,genetic mineralogy characterization of garnet,pyroxene,pyrite and chalcopyrite were carried out and elemental analyses of C,H,O,S and Pb were performed.The results show that the garnet belongs to grossular-andradite,and the andradite was formed prior to grossular;whereas the pyroxene is mainly consisted of sahlite and diopside,indicating that the early acid ore-forming stage had high temperature and high oxygen fugacity.In the Hongshan-Hongniu deposit,the pyrite is enriched in Fe and depleted in S,with Co/Ni> 1,suggesting a magmatic hydrothermal source.The garnet yielded δ18O and δD values of 6‰-8.8‰ and-93.1‰--149‰,respectively,and the calcite from massive sulfide ranged in δ13CvPDB and δ18Ov-sMow values of-2.7‰-2.5‰ and 11.4‰-23.4‰,respectively,suggesting that the magmatic hydrothermal fluid was dominant whilst meteoric water was negligible during mineralization in the Hongshan-Hongniu deposit.34δ S content of the sulfides and quartz monzonite porphyry spanned small ranges from 3.8‰ to 5.6‰,and from 4.7‰ to 7.8‰,respectively,demonstrating that the ore-forming materials were originated from the quartz monzonite porphyry which had a single crustal source with material contribution from the mantle.Lead isotopes exhibited the features of the lower crust and a minor derivation from the upper crust and orogenic lead.%本文研究了中甸弧南段红山-红牛铜矿主要夕卡岩矿物石榴石和辉石成因矿物学特征,显示矿区石榴石为钙铁-钙铝石榴石系列,早期多为钙铁榴石,晚期为钙铝榴石.矿区部分石榴石在背散射光下可以观察到明显的环带结构,钙铝榴石和钙铁榴石含量差别越大环带越明显.矿区辉石主要为次透辉石和少量的透辉石,表明夕卡岩早期成矿流体为高温、酸性和高氧逸度环境.矿区黄铁矿强富铁亏硫且Co/Ni>1,黄铜矿S、Fe和Cu含量较稳定只含有少量的C、Ni和Se,均指示为高温岩浆热液成因.金属硫化物34S众值出现在3.8‰~5.6‰,同时代的石英二长斑岩34S在4.7‰~7.8‰,表明硫主要来自石英二长斑岩.金属矿物和石英二长斑岩铅同位素特征表明,铅主要来自上地壳.石榴石δ18Ov SMOW=6‰~8.8‰,成矿流体δ18OH2O=4.6‰~7.8‰,反映成矿流体主要来自岩浆热液,且成矿流体存在明显的沸腾作用.夕卡岩矿体中的方解石和围岩方解石C-O同位素研究,指示块状硫化物中的方解石来自岩浆流体,含有硫化物细脉的围岩大理岩中的方解石来自围岩的再结晶作用.