川东南脉状萤石－重晶石矿床流体包裹体研究

FLUID INCLUSION STUDY OF VEIN FLUORITE AND BARITE ORE IN SOUTHEAST SICHUAN

川东南脉状萤石──重晶石矿床主要产于下奥陶统碳酸盐岩中，其成矿与岩浆活动无明显联系．成矿温度较低，成矿流体富含ＮａＣｌ和Ｈ＿２Ｏ，ＣＯ＿２和ＣＨ＿４的含量较低，Ｎ＿２，Ｏ＿２及Ｈ＿２的含量甚微。成矿介质水主要来源于地层水（如封存的海水、盆地压实脱水等）及大气降水，成矿温度、δ￣Ｄ值、盐度、Ｎａ￣＋／Ｋ￣＋比值以及矿石中有机包裹体的在在均表明本区萤石和重晶石的成矿流体类似于密西西比河谷型矿床的成矿热卤水，其形成与介质水溶滤本区寒武系蒸发岩有关。

The vein fluorite and barite ore occurs mainly in lower Ordovician carbonate rocks in southeast Sichuan. There is no obvious relationship between the mineralization and igneous activi-ty. Fluid inclusion study shows that mineralization temporatures are low; the ore-forming solution are rich in NaCl and H_2O,with minor amounts of CO_2 and CH_4 and trace of N_2 O_2 and H_2.The isotope composition of hydrogen and oxygen indicates that the solution originated essentially from formation waters(e,g.trapped seawater or dehydration)and meteoric waters. Mineralization tem-Peratures,values of δD, Na￣+/K￣+,and the salinity, combined with organic inclusions in the vein otes, suggest that the ore-forming solution is similar to that of Mississippi Valley- type Pb-Zn-F deposits,and characterized by hot brines which are related to leaching of Cambrian evaporites in southeast Sichuan.