横岭关铜矿床地球化学研究

GEOCHEMISTRY OF THE HENGLINGUAN COPPER DEPOSIT

对横岭关铜矿床中稀土元素、同位素和矿物包裹体地球化学研究表明，矿床形成温度为３５０℃±３０℃；压力为３８×１０~５Ｐａ～２４０×１０~５Ｐａ；盐度为３０ｗｔ％～４２ｗｔ％；ｌｏｇｆｏ_２为－３０．４１～－３１．４７；ｌｏｇｆｓ_２为－５．４～－８；ｐＨ值为７．３；ｌｏｇｆｃｏ_２为－２．４９；铜的溶解度（ｌｏｇｍ_（Ｃｕ））为－５．８７～－２．２１。围岩的铅－铅同位素年龄为１７７５×１０~６ａ，矿石的铅－铅同位素年龄为１８４５×１０~６ａ；矿石硫同位素组成，δ^（３４）Ｓ为－８．１‰～３６．９‰，显示出硫同位素为非平衡特征；碳酸盐岩的碳同位素组成，δ^（１３）Ｃ为－７．１‰～－２．６‰，δ^（１３）Ｃ_（∑Ｃ）为－５．３‰；成矿流体的氢氧同位素组成具有变质热卤水的特点，认为该矿床属于变质热卤水成矿。

Studies of geochemistry of REE,isotope and mineral inclusion in the Henglinguan copper deposit indicate that its forming temperature is 350℃±30℃;Pressure is 38× 10￣5Pa～240×10￣5Pa;Salinity is 30wt%～42wt%;Logfo_2 is -30. 41～-31. 47;Logfs_2 is-5.4～-8;pH is 7. 3;Logfco_2 is-2.49;Solubility of Copper(logmCu) is-5.87～-2.21.The Pb-Pb isotope dating in the country rock is 1775×10￣5a,and that is the ore is 1845×10￣6a,Sulfur isotope composition in the ore is-8.1‰～36.9‰,showing nonequilibrium sulfur isotope. The carbon isotope composition is-7.1‰～2.6‰,and the δ￣(13)C_(∑C) is-5.3‰ in carbonate rock. The hydrogen and oxygen isotope composition of the mineralization fluid is charactered by metamorphic hot brine Therefore the metallogenesis of the deposit should be considered as metamorphic hot brine.