稀有金属花岗岩岩浆—热液的形成路径和成矿过程——以广西恭城栗木矿田为例  

Forming path of magmatic—hydrothermal system of rare metal granite and its ore-forming process——A case study in the Limu orefield,Gongcheng County,Guangxi

作　　者：梁磊 董业才 高嵛飞 张玲[2] 徐桃 LIANG Lei;DONG Yecai;GAO Yufei;ZHANG Ling;XU Tao(China Nonferrous Metals(Guilin)Geology and Mining Copany Limited,Guilin,Guangxi,541004;Institute of Karst Geology,Chinese Academy of Geological Science/Key Laboratory of Karst Dynamics,Ministry of Land and Resources&Guangxi Zhuang Autonomous Region,Guilin,Guangxi,541004)

机构地区：[1]中国有色桂林矿产地质研究院有限公司,广西桂林541004 [2]中国地质科学院岩溶地质研究所,国土资源部/广西壮族自治区岩溶动力学重点实验室,广西桂林541004

出　　处：《地质论评》2021年第3期722-735,共14页Geological Review

基　　金：全国危机矿山接替资源勘查项目“广西恭城县栗木锡矿接替资源勘查”(编号:200645091);广西区大规模地质找矿项目“广西恭城县五福锡钽铌矿普查”(编号[2010]604)的成果。

摘　　要：关于稀有金属花岗岩的成矿流体来源及与岩浆演化的成因关系长期存疑。现以华南稀有金属花岗岩的典型代表广西栗木花岗岩为例,通过对成矿地质体花岗岩垂向分带的岩相学特征及矿床地质特征的深入研究,分析岩浆—热液的形成演化路径与成矿过程。研究表明,岩浆演化除了结晶作用外,还有大规模的气—液分离,岩浆—热液的形成主要与其中的气—液分离有关,不是传统意义上的岩浆残液。不同成因类型矿床的成矿流体均来自第二次气—液分离形成的二级残余富气流体相构成的岩浆—热液,岩浆—热液系统由3个不同空间分布的分支系统组成,每个分支系统在不同环境下以交代、结晶等不同形式与上部地质体作用,演化形成成矿流体,最后形成岩体接触带及附近的不同成因类型的矿床和以细晶岩为底部边界的成分分带。研究成果还原了岩浆演化形成岩浆—热液的详细路径,构建了成矿模型,对深入认识花岗岩的岩浆演化与成岩成矿作用具有启示意义。Objectives: Learn more about the forming path of magmatic—hydrothermal system of rare metal granite and its ore-forming process.Methods: Taking Limu granite,a typical representative of rare metal granite in South China,as a case of study,come to understand the forming path of magmatic evolution through a in-depth study of petrography on vertical zoning of the granite. Then,by correlating magmatic evolution with geological characteristics of mineral deposit,deduce how the magmatic—hydrothermal system come into formation and ore-forming process.Results:(1) In addition to crystallization,there is also large-scale gas—liquid fractionation in magmatic evolution,and the formation of magma—hydrothermal fluids is mainly related to the gas—liquid fractionation.Therefore,the magma—hydrothermal fluid is not the residual magma solution in the traditional sense.(2) The forming path of magma—hydrothermal fluids is: large-scale gas—liquid fractionation takes place in the water-rich magma during its emplacement,forming gas-rich fluid and new remain molten phase magma. Then the gas-rich fluids rise to three different spaces where,they will undergo the second time gas—liquid fractionation as decrease of temperature and generate the residual gas-rich fluids which is the so-called magmatic—hydrothermal fluid.(3)Oreforming fluids of all sorts of mineral deposits in Limu orefield are all from the residual gas-rich fluids( magma—hydrothermal fluids) formed by two times of magmatic gas—liquid fractionation.(3) The magmatic—hydrothermal system consists of three branches which located in three different spaces,each of them interacts with different surrounding geological bodies by the way of hydrothermal alteration or crystallization,forming different types of deposits and vertical zoning.Conclusions: In the paper,we reconstruct the forming path of magmatic—hydrothermal system of rare metal granite and ore-forming process,and set up a new metallogenic model correlative. The results of the study would have enligh

关 键 词：稀有金属花岗岩 岩浆—热液 形成路径 成矿过程 岩浆残液 广西栗木 

分 类 号：P314[天文地球—固体地球物理学]