哀牢山北段蛇绿岩中构造蚀变岩型金矿床特征

哀牢山北段蛇绿岩中构造蚀变岩型金矿床主要产于蛇绿岩上部的玄武岩和火山碎屑岩中，并受北西向断裂构造控制。区内分布有喜玛拉雅期煌斑岩和花岗闪长斑岩等脉岩，其与成矿作用密切相关。围岩蚀变以碳酸盐化为主，其次是绢云母化和黄铁矿化。矿石主要金属矿物为黄铁矿、毒砂、辉锑矿；包裹体成分以Na+、Zn2+、Cl-、SO42-、H2O和CO2为主；主要微量元素是As、Sb、W；稀土元素表现出轻稀土降低和重稀土相对增加的演化特征。硫、氧同位素研究表明，该矿床属于以岩浆热液为主，伴有部分地下水加入的中低温热液矿床。

THE CHARACTERISTICS OF THE GOLD DEPOSITS OF TECTONIC ALTERED ROCK TYPE IN THE OPHIOLOTE OF NORTH AILAO MOUNTAIN

The gold deposits of tectonic altered rock type in the ophiolite of Noith Ailao Mountain are located in the basalts and pyroclastic rocks of the upper ophiolite. The gold deposits are all under the control of northwest faulted structure, and associated with the different veins of lamprophyres and granodioritic porphyrys which have to do with ore-forming process. First wall-rock alteration is carbonation, second are sericitization and pyritisation. Main metallic sulphide ores are pyrites, arsenopyrites, stibnites, and form the different assemblages of min-eralization. The forming temperature of the gold deposits is low- to -moderate. The compo-sition of the fluid inclusions is abundant in Na+, Zn2+, Cl-; SO42- , H2O, CO2and so on. The main enrichmicroelements of the gold deposits are As, Sb, W, and REE evolutionary charac-teristics are LREE depressing and HREE increasing. Sulfur and oxygen isotope composition displays that the gold deposits are low -to -moderate hydrothermal deposits and their ore -forming solution is mainly composed of the magmatic hydrothermal solution which is added in some underground water.