熔体包裹体在估算花岗岩类矿床形成压力(深度)方面的应用  

Application of melt inclusions to estimating ore-forming pressure(depth) of granite-related ore deposits

作　　者：李建康[1,2] 张德会[3] 李胜虎[3] 

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054 [2]中国地质科学院矿产资源研究所,北京100037 [3]中国地质大学,北京100083

出　　处：《矿床地质》2011年第6期1002-1016,共15页Mineral Deposits

基　　金：全国危机矿山接替资源找矿项目(20109903);国家自然科学基金项目(40702014);国土资源部公益性行业科研专项经费(Sino-probe-03-01);中央级公益性科研院所基本科研业务费专项资金(K1001)资助

摘　　要：在花岗岩类矿床中,花岗岩浆分异出富挥发分熔体/流体的过程,是导致岩浆就位和成矿元素迁移、富集的关键因素之一。在该过程中,同时捕获的不同类别的熔体包裹体和流体包裹体可以互相限定捕获条件,由此可以建立一系列与熔体包裹体有关的地质压力计,进而得到相关分异作用发生的深度。这些深度数值,对于指导花岗岩地区的找矿工作具有重要价值。与熔体包裹体有关的压力计主要分为与硅酸盐熔体包裹体共生的流体包裹体地质压力计、硅酸盐熔体包裹体地质压力计和富子晶包裹体地质压力计。这些压力计使用的难点主要是均一实验,实验设备主要有Linkam高温热台系统、冷封式高压釜和热液金刚石压腔,三者各有优缺点。国内许多实验室已经具备开展熔体包裹体均一实验的条件。在中国,如南岭地区,许多花岗岩类矿床中存在花岗岩晶洞、花岗岩中的似伟晶岩囊体、花岗岩与围岩接触带的似伟晶岩壳、花岗伟晶岩以及富挥发分花岗岩,这些地质体保留了熔体分异出富挥发分熔体/流体的痕迹,是应用与熔体包裹体有关的压力计的良好对象。In the granite-related ore deposits, the differentiation of volatile-rich melt or fluid from granitic magma con stitutes one of the key factors controlling the emplacement depth as well as the migration and enrichment of ore forming elements. In these processes, the coexisting melt and fluid inclusions can mutually constrain entrapment conditions, and then a series of geobarometers can be induced. The depth estimated by such barometers repre sents differentiation that occurred and can help ore exploration work in granite areas. These barometers include methods of fluid inclusions coexisting with melt inclusions, melt inclusions and crystal-rich inclusions. The main difficulty in application of these barometers is the melt inclusion microthermometry. At present, Linkam serial heating stage, cold-seal pressure vessels, and hydrothermal diamond anvil cell are the main facilities for heating melt inclusions, which have their respective advantages and shortcomings. In China, especially in Nanling re- gion, many granite-related ore deposits have geological features suggesting the differentiation of magma, which can meet the requirements of applying barometers related to melt inclusions to the study of ore-forming depth.

关 键 词：地球化学 花岗岩类矿床 熔体包裹体 地质压力计 成矿深度 

分 类 号：P599[天文地球—地球化学]