滇东南官房钨矿床矽卡岩矿物学特征及其地质意义  

Skarn mineral charactersistics of Guanfang tungsten deposit and its geological significance,southeastern Yunnan Province,China

作　　者：蔡金定 刘益[1] 孔志岗[1] 李文昌[1] 陈港 朱俊[1] CAI JinDing;LIU Yi;KONG ZhiGang;LI WenChang;CHEN Gang;ZHU Jun(Kunming University of science and technology,Faculty of Land Resources Engineering,Kunming 650093,Yunnan,China;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650093 [2]中国地质科学院矿产资源研究所,北京100037

出　　处：《矿床地质》2024年第3期527-546,共20页Mineral Deposits

基　　金：昆明理工大学“双一流”科技专项项目(编号:202202AG050006);校人培基金资助(编号:KKZ3202221022)联合资助。

摘　　要：官房钨矿床位于滇东南薄竹山W多金属矿集区,是近年来新发现的大型白钨矿床。矽卡岩多产于层间破碎带,呈似层状、透镜状和脉状,一般不与花岗岩体接触而形成远端矽卡岩(深部揭露有少量产于接触带),矽卡岩矿物发育。为进一步查明矽卡岩矿物学和矿物化学特征,揭示矽卡岩形成环境,探讨矽卡岩与矿化类型之间的关系,笔者采集了KT3近端矽卡岩与KT5远端矽卡岩进行对比,通过开展系统的矿物学镜下观察,利用EMPA进行石榴子石成分分析,LA-ICP-MS对典型的矽卡岩矿物进行了单矿物分析。研究表明,官房钨矿床矽卡岩属典型钙质矽卡岩,矽卡岩矿物主要有石榴子石、辉石、符山石等,其中石榴子石为钙铝榴石-钙铁榴石系列,辉石为透辉石-钙铁辉石系列,符山石属普通符山石。由近端矽卡岩向远端矽卡岩,石榴子石主要成分由钙铝榴石向钙铁榴石转化;辉石几乎全部为透辉石向透辉石、钙铁辉石的组合转化,石榴子石与辉石的特征表明矿床的矽卡岩由还原型矽卡岩转为氧化型矽卡岩;KT5形成条件较KT3氧逸度更高,两者流体交代方式以扩散交代为主。石榴子石、辉石端员组分及Mn/Fe、Mg/Fe比值稍高的特征,综合指示其矿化类型属于铁铜锌等多金属矿化类型;符山石中较低的w(W)可作为钨矿找矿标志。The Guanfang tungsten deposit,located in the Bozhushan tungsten polymetallic ore concentration area in Southeast Yunnan,is a newly discovered large scheelite deposit in recent years.The skarn mostly occurs in the interlayer fracture zones of the strata,in the form of layered,lenticular and vein.Most of the skarns do not contact with the granite body and form the distal skarn(the deep exploration revealed that a small amount occurs in the contact zone),and the skarn minerals are developed.In order to further identify the mineralogical and mineralchemical characteristics of the skarn,reveal the formation environment of skarn,and explore the relationship between skarn and mineralization types,the rock samples from near-end skarn(KT3)and distal-end skarn(KT5)were collected for comparison.A systematic mineralogical observation was undertaken,and analysis of garnet composition and In-Situ analysis of typical skarn minerals were carried out using EMPA and LA-ICP-MS,respectively.The study shows that the skarn of the Guanfang tungsten deposit belongs to the typical calcareous skarn,and the skarn minerals mainly include garnet,pyroxene,and vesuvianite,among which garnet is grossular-andradite series,pyroxene is diopside-hedenbergite series,and vesuvianite is the common vesuvianite.From the nearend skarn to the distal skarn,the main composition of garnet changes from grossular to andradite;the pyroxene transforms from almost purely diopside to the combination of diopside and hedenbergite.The characteristics of garnet and pyroxene indicate that the skarn of the deposit has changed from the reduced skarn type at near-end to the oxidized skarn type at distal end;the oxygen fugacity of KT5 is higher than that of KT3,the fluid metasomatism of KT5 and KT3 is mainly diffusion metasomatism.The characteristics of garnet and pyroxene end-member components and slightly higher Mn/Fe and Mg/Fe ratios comprehensively indicate that the mineralization type belongs to Fe-Cu-Zn polymetallic mineralization type;The lower W content in vesuvian

关 键 词：矽卡岩 矿物学 矿物化学 官房钨矿床 薄竹山 

分 类 号：P618.67[天文地球—矿床学]