甘肃李家沟铅-锌矿床成矿地球化学条件的初步研究

GEOCHEMICAL CONDITIONS OF METALLIZATION OF THE LIJIAGOU Pb-Zn DEPOSIT, GANSU PROVINCE

甘肃李家沟铅一锌矿床属同生热液沉积-变质热液弱改造型层控矿床。文中按不同成矿阶段详尽地探讨了该矿床的成矿物理化学条件。依据对矿床成矿物质来源的系统研究,作者认为,该矿床成矿金属物质、矿石硫和成矿流体的水主要分别取自基底地层、海水硫酸盐的还原硫以及渗流加热的大气降水和部分回灌海水。最后,本文建立了该矿床的成矿模式。

This paper deals systematically with the geochemical conditions of metallization, genesis and ore-forming material source of the Li jiagou Pb-Zn deposit in the Xicheng orefield. The following conclusions have been reached: 1) the ore-forming metals in this area were mainly derived from the basement rather than ore-bearing strata (the Middle Devonian). This view has been proved by the systematic studies of the stratigraphic geochemistry and lead isotopic study; 2) the ore sulfur of this deposit was mainly derived from marine sulphates through biogenic reduction; 3) the water of the mineralizing fluids of the deposit was derived from the heated infiltrating meteoric water and partialy from the recharged sea water; 4) the Li jiagou deposit should belong to the syngenetic hydrothermal deposition and metamorphozed hydrothermal weakly reworked stratabound Pb-Zn deposit. Finally, the metaliogenic model of this deposit has been established which shows directly the geochemical conditions of metallization of the deposit.