湖南省永兴县新生矿区隐伏岩体地质地球化学特征及其与成矿的关系

Geological and Geochemical Characteristics of the Concealed Xinsheng Granite Orebodies and Their Relationship with the Metallogeny in Yongxing County,Hunan Province

湖南省永兴县新生矿区锡铜多金属矿床是南岭地区典型的矽卡岩型矿床之一,矿体在围岩、矽卡岩和岩体中均有产出。矿区内地表无岩体出露,但其存在隐伏岩体,该隐伏岩体在深部可能与大义山岩体相连。岩石地球化学特征表明,矿区K/Rb值不到100,说明该区岩浆分异作用强烈,易于成矿;而铝饱和指数和稀土元素球粒陨石标准化分布型式图则说明矿区铝岩浆来源比较复杂,既有壳源的,也有壳源混合源的。研究还表明,矿区及大义山岩体为A型花岗岩,而非之前所认为的S型花岗岩。该矿床的形成除受构造特征的控制外,富含Cu、Sn等成矿元素及F等挥发组分的岩浆侵位是本区最主要的控矿因素。

The Xinsheng tin-copper polymetallic deposit in Yongxin County, Hunan Province is one of the typical skarn deposits in the Nanling area. Its orebodies occur in the wall rock, skaru and granite bodies. Granite bodies are not exposed on the surface,but concealed bodies exist there, which may be connected with the Dayishan granite bodies at depth. Geochemical characteristics of granite bodies in the Xinsheng ore district indicate K/Rb value is less than 100, and strong magmatic differentiation may be favorable to ore formation. And the source of magma is complex, including both crust source and crust-mantle mixed source. The granite bodies in the Xinsbeng ore district and the Dayishan body are not of S-type, but A-type. The deposit is controlled by structural features, and the intrusion of magma which contains such ore-forming elements as Cu and Sn, and volatile components F is the most signifi- cant ore-controlling factor.