锡铜共生矿床的研究现状、问题与展望

Research status,questions and prospects of Sn-Cu coexisting deposits

文章在总结全球锡铜共生矿床时空分布规律的基础上,重点从成矿地质特征、热液蚀变组合、金属来源和成矿动力学背景等方面综述了锡铜共生这类矿床的研究进展,并总结了锡铜共生矿床中岩浆过程和热液过程。研究表明,锡铜矿床主要发育在与俯冲相关的板块边缘,弧后、后碰撞等岩石圈伸展环境,并伴随着强烈的壳幔相互作用。全球锡铜共生矿床的形成时代以晚古生代和中生代为主,其空间分布广泛但局部集中产出,主要分布在中国华南、南美玻利维亚、欧洲康沃尔和厄尔士以及俄罗斯远东地区。根据成矿特征,这类矿床可将分为2类:第一类矿区除发育与锡成矿有关的高分异、还原性钛铁矿系列岩浆岩以外,还发育有大规模基性或碱性岩浆活动;第二类矿区则仅发育与锡成矿有关的岩浆岩,并未发育基性或碱性岩浆作用。目前对于锡和铜的物质起源仍有争议,其中锡主要来源为高分异花岗岩,而铜的物质来源比较复杂。在前人的研究基础上,文章提出对锡铜共生矿床的研究展望:①采用多种非传统稳定同位素(Sn、Cu、Ba同位素)进行联合示踪;②在开展精细矿物学特征研究的基础上,利用不同阶段的矿石矿物和脉石矿物,进行原位地球化学分析,查明锡铜共生的精细化过程和成矿物源归属。上述问题的深入研究或将提高对锡铜共生矿床成矿过程的认识,为该类矿床的找矿勘查工作提供理论支撑。

In this paper,based on the characteristics of the temporal and spatial distribution of Sn-Cu coexisting deposits in the world,we summarize the research progress of Sn-Cu deposits including metallogenic geological charac-teristics,hydrothermal alteration assemblages,metal sources and metallogenic dynamics,as well as the magmatic and hydrothermal processes.Previous studies have shown that Sn-Cu deposits are generally formed in the plate margin related to subduction,the lithospheric extensional environment such as post-arc and post-collision,with strongly crust-mantle interactions.Sn-Cu deposits were mainly formed in the Late Paleozoic and Mesozoic and distributed in several metallogenic belts including South China,western South America and Cornwall and Erzge-birge in Europe,and the Russian Far East.According to the mineralization characteristics,Sn-Cu deposits can be divided into two types;the first type develops coeval large-scale mafic or alkaline magmatic activities plus the Sn related highly-fractionated reduced(ilmenite series)granitic rocks;the second type only develops Sn-related gra-nitic rocks without mafic or alkaline magmatism.Currently,the metal source of Sn-Cu deposits still remains largely controversial;tin comes from highly fractionated granites but the Cu source is more complex.This paper suggests research prospect of Sn-Cu mineralization:①combine multiple unconventional stable isotopes(e.g.,Sn,Cu,Ba isotopes)as a tracer for metal source;②based on detailed mineralogy characteristic,utilize in situ geo-chemical analysis of ore minerals and gangue minerals at different stages,to decipher the precise mineralization processes and metal source of Sn and Cu.Solving these problems may help us improve the understanding of the coexisting tin and copper mineralization processes and provide new basis for the exploration of Sn-Cu deposits.