THE RESEARCH AND UNDERSTANDING ON ORE-FORMING FLUID IN GOLD-BEARING QUARTZ VEIN DEPOSITS

Gold-beating quartz vein type is common in gold deposits. In this type, gold occurs mainly in quartz, pyrite and other metal sulfides as intergronular gold, fissure-filling gold and wrapped gold. At present, the analytic results from fluid inclusions in quartz are used to understand the composition of ore-forming fluid for this type of deposits. However, it is confirmed by the synthetic studies both in field and laboratory, that the completion of gold deposit covers several ore-forming phases. There are quartz and metal sulfides in e.ach step, and the crystallization of quartz is obviously earlier than that of metal sulfides. What's more, the existing of fissure-filling gold and wrapped gold in metal sulfides also indicates that the gold deposited at the same time as or even later than the sulfides did. Therefore, there is a time interval between the fluids for gold movement, deposition and crystallization and those of quartz veins. Gold mineralization is closely related to metal sulfides. The researches on the fluid inclusions in metal sulfides from gold-bearing quartz vein deposits are more meaningful to realize the origin of ore-forming maters during the main ore-forming step than on the fluid inclusions in the quartz veins.