与A型花岗岩有关锡矿的云英岩化蚀变矿化地球化学:以新疆卡姆斯特和干梁子矿床为例  

Greisenized Alteration-Mineralization Geochemistry of the Tin Deposit Related to A-Type Granite:Case Study on the Kamusite and Ganliangzi Deposits,Xinjiang

作　　者：陈言飞 王玉往[3] 王京彬[3] 王莉娟[3] 唐萍芝[3] 石煜[3] 赵路通[3] Chen Yanfei;Wang Yuwanga;Wang Jingbin;Wang Lijuan;Tang Pingzhi;Shi Yu;Zhao Lutong(School of Earth Sciences,China University of Geosciences,Wuhan 430074,China;Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;Beijing Institute of Geology for Mineral Resources,Beijing 100012,China)

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074 [2]中国地质科学院地质研究所,北京100037 [3]北京矿产地质研究院,北京100012

出　　处：《地球科学》2018年第9期3154-3168,共15页Earth Science

基　　金：国家重点基础研究发展规划(973计划)项目(No.2014CB440803)

摘　　要：新疆准噶尔盆地东部卡拉麦里地区发育我国典型的A型花岗岩型锡矿.通过对该区卡姆斯特和干梁子两个锡矿4个矿化蚀变带的岩相学及地球化学研究,发现矿体和致矿岩体是同源岩浆演化的结果,矿体是岩浆分异演化末期向流体演化过程中形成的.矿床的蚀变分带模式可分为两种:(1)(红色)细粒黑云母花岗岩→云英岩化细粒花岗岩→含锡石英脉;(2)细粒黑云母花岗岩→含锡云英岩→含锡石英脉.其蚀变带中岩石的地球化学组分总体迁移规律为:SiO_2迁入,Na_2O、K_2O迁出,Fe_2O_3总体表现为迁入,Th/U值不断降低,表明硅化和碱交代作用贯穿整个成矿过程,成矿环境由碱性向酸性变化,并伴随氧逸度的升高.F、Cl、W、Cu、Bi、In、Pb、Rb、Nb、Ta等元素与成矿元素Sn的迁移、富集和沉淀密切相关,其中F和Cl是迁移过程中最活跃的组分,是Sn元素最大的"搬运工",Sn元素的富集与W、Cu、Bi、In等元素迁移呈正相关,反映流体作用与Sn成矿密切相伴,而与Pb、Rb、Nb、Ta等元素的迁移呈负相关,反映致矿岩体自身元素的稀释和带出,Sn的富集和成矿是在岩浆向流体演化过程中完成的.The typical tin ores related to A-type granite have been discovered in Kalamaili region,east of the Junggar,North Xinjiang.However,little has been known about the metallogenetic mechanism of the tin ores so far.This study on petrology and geochemistry of four mineralization-alteration zones from the Kamusite and Ganliangzi tin deposits show that the ores and metallogenic rock body are the products of the fractional crystallization of homologous magma with the ores forming at the later stage,and there are two alteration zoning patterns：（1）（red）fine-grained Bt-granite→greisenized fine-grained granite→tinbearing quartz veins;（2）fine-grained Bt-granite→tin-bearing greisen→tin-bearing silicification veins.The elements migration of the altered zone show that SiO2 was externally supplied,Na2O and K2O moved out in varying degrees,more Fe2O3 was supplied than lost,and Th/U ratios kept decreasing in the whole mineralized process,which suggests that the on-going silicifi-cation and alkali metasomatism in the whole process result in the changes of metallogenic environment from basic to acidic and the increases of oxygen fugacity.The migration of trace elements（eg.W,Cu,Bi,In）was significantly positively associated with the enrichment of tin,while that of others（eg.Pb,Rb,Nb,Ta）was negative,together with the most active component of F and Cl,and these elements played important roles in the process of migration,enrichment and precipitation of tin.This indicates that the elements from the metallogenic rock body were lost while the fluid played an important role in the process of Sn mineralization,and the enrichment and mineralization of Sn was probably caused in the transition stage from magmatic to hydrothermal system.

关 键 词：锡矿 A型花岗岩 蚀变矿化分带 元素迁移规律 成矿条件 地球化学 

分 类 号：P614[天文地球—矿床学]