湘西合仁坪金矿床硫、铅同位素地球化学

Sulfur and lead isotope geochemistry of Herenping gold deposit, western Hunan

湘西柳林汊一带广泛分布钠长石_石英脉型金矿,合仁坪金矿床是其典型代表。文章对合仁坪金矿床的硫、铅同位素进行了研究,并与区域石英脉型金矿床进行对比,探讨了该矿的成矿物质来源,并初步确定了其矿床成因。研究表明,合仁坪金矿床硫化物的δ34S值范围较窄（-4.8‰～4.4‰）,平均为-0.6‰,该矿床的硫为深源硫,由深部变质流体带入;铅的同位素组成较均一,并表现出明显的造山带铅的特点。结合区域成矿作用,进一步研究揭示,合仁坪金矿床为一典型的造山型金矿,其成矿可能与湘西雪峰山地区加里东期的造山作用有关。

Albite_quartz lode gold deposits are widespread in the Liulincha belt, western Hunan. Among them, the Herenping deposit is a typical one. Sulfur and lead isotopic compositions of ores in the Herenping deposit were analyzed in this study, compared with the quartz lode gold deposits in western Hunan, the ore_forming materials＇ source for the Herenping deposit was investigated, and its ore genesis was preliminarily ascertained. It is revealed that the δ34S values of sulfides in ores range narrowly from-4. 8‰ to 4. 4‰, with an average of 0. 6‰, which suggests that the sulfur in ores was mainly derived from the deep_seated source brought by the metamorphic fluids. The lead isotopic compositions in ores are relatively uniform and display obvious orogenic lead signature. In comparison with other gold deposits in western Hunan, it can be further concluded that the Herenping lode gold deposit is a typical orogenic gold deposit probably associated with Caledonian orogeny in the Xuefeng uplift.