吉林放牛沟硫铁多金属矿床矿物地球化学及矿床成因

MINERAL GEOCHEMISTRY AHD GENESIS OF THE FANGNIUGOU PYRITE—POLYMETALLIC DEPOSIT, JILIN PROVINCE

本文总结了黄铁矿、闪锌矿的成因地球化学标志;阐明了黄铁矿中元素在空间上的分带规律和在成矿过程中时间上的演化规律;建立了反映上述分带规律的回归方程组;论证了本矿床矿石中黄铁矿与磁黄铁矿间、矿石矿物与花岗岩副矿物磁铁矿间的成因联系;类比了国内外铅锌矿床上述矿物的地球化学特征。由此得出结论:放牛沟硫铁多金属矿床系岩浆热液成因,其成矿物质主要来自后庙岭花岗岩深部岩浆源。铅锌矿主要在中温条件下形成,接触带矿体与外接触带矿体属同一成矿系列。放牛沟矿床与后庙岭花岗岩系同一岩浆—热液系统的产物。

In this paper, geochemical characteristics of pyrrhotite, magnetite, sphalerite and galena were studied; the genetic geochemical indexes of pyrite and sphalerite were summerized; the zoning patterns in space and the evoloution law in the process of mineralization of the trace elements in pyrite were expounded; the regression equations which reflect the vertical zoning patterns of elements in pyrite were established; the genetic connection between pyrite and pyrrhotite, ore mineral magnetite and accessory mineral magnetite in granite were expounded; the geochemical characteristics of main ore minerals in some related ore deposits at home and abroad were compared with those of the Fangniugou deposit. From what we mentioned above, it can be concluded that the Fangniugou pyrite-polymetallic deposit may be referred to a magmatic hydrothermal genesis and formed under mesothemal condition; the orebodies in the internal & external contact zones of intrusion all belong to the same metallogenic series; the ore-forming elements probably came from the anatectic magma chamber of the Houmiaoling granite; the Fangniugou ore deposit and the Houmiaoling granite were derived from the same magmatic hydrothermal sysytem. The regression equations and other geochemical indexes established in this paper can be used in the evaluation of mineralization-alteration zone and primary geochemical anomalies.