湖南瑶岗仙钨矿床成矿流体演化特征研究

Characteristics and evolution of ore_forming fluids in Yaogangxian tungsten deposit, Hunan Province

瑶岗仙矿床位于湖南省郴州市瑶岗仙镇,是世界著名的钨矿床。近几年,随着云英岩析离体的发现,对于成矿流体的演化过程有了新的认识。文章通过对瑶岗仙石英脉型黑钨矿矿床的中粒碱长花岗岩、云英岩析离体和石英脉3个阶段地质体的石英中的流体包裹体进行显微测温和激光拉曼光谱分析,并对云英岩析离体中的熔流包裹体进行加热熔化实验,初步证明了瑶岗仙矿床石英脉型黑钨矿阶段成矿流体的演化是由花岗质岩浆→浆液过渡态岩浆→岩浆热液的一个完整连续的过程,而且成矿流体以富含挥发分为特征。并结合地质现象,提出浆液过渡态流体与成矿作用具有直接联系。

Located at Yaogangxian Town in Chenzhou City of Hunan Province, the Yaogangxian deposit is one of the most famous tungsten deposits in China. Recently, with the discovery of segregation bodies of greizen, some new understanding concerning the evolutionary process of ore-forming fluids in the Yaogangxian deposit has been obtained. This paper focuses on the study of inclusions in quartz from three evolution stages in the Yaogangxian deposit, during which medium grained alkali feldspar granite, greizen segregation body and quartz veins were formed, respectively. The results of the microthermometric experiments and laser Raman spectroscopy on fluid inclusions of quartz and heating-melting experiments on fluid-melt inclusions of greizen segregation bodies indi- cate that a complete successive evolutionary process of the ore-forming fluids in the Yaogangxian deposit actually evolved from granitic lava state through lava-fluid transitional state to magmatic hydrothermal state, and the ore- forming fluids were rich in volatiles. Combined with geological background, the authors hold that there existed the direct relationship between the lava-fluid transitional fluid and the mineralization in the Yaoganxian deposit.