河南祁雨沟金矿流体包裹体研究

FLUID INCLUSION STUDIES OF QIYUGOU GOLD DEPOSITS, HENAN

流体包裹体研究表明祁雨沟金矿床形成于高中温浅成环境。从早成矿期至晚矿化期，成矿温度、成矿流体盐度、ｐＨ值、ｆＯ２、成分及氢氧同位素组成呈现系列变化。成矿流体主要来自岩浆热液，属Ｈ２－ＮａＣｌ－ＣＯ２体系，晚期有一定量大气降水加入。

There are cryptoexplosive breccia gold deposits and structurally ruptured metasomatic gold depostis in Qiyugou area, Henan. The two types of the gold deposits are closely associated with the distribution of the calc-alkaline intrusive granitoids of Mid-Late Yanshan Epoch. Recent studies have shown that they have contempeeraneous mineralization of gold and similar hydrothermal alterationmineralization characteristics. It is cleared that the whole ore-forming process in the two types of the gold deposits can be divided into“Vanward-”, Main-”and“Late-alteration-mineralization”periods. Fluid inclusion studies indicate that the Qiyugou gold deposits were formed at high to intermediate temperature and shallow environment. The oreforming temperature, salinity, pH, fo_2, and chemical compositions and isotopic coimpositions of ore-forming fluid changed from the early to the late. The compositions of the fluid inclusions and isotopic compositions of oxygen, hydrogen and sulfur suggest that the ore-forming fluid was mainly of magmatic, and close to the H_2O-NaCl-CO_2 system. A suitable amount of rain water was added into the ore-forming liquid at later mineralization period. The phase seperation of the ore-forming fluid was an effective mechanism of the gold deposition.