云南老君山片麻岩穹隆中含绿柱石石英脉的显微构造与流体特征及地质意义  

Microstructure and fluid characteristics of beryl-bearing quartz vein in the gneiss dome of Laojunshan,Yunnan,and their geological significance

作　　者：李清松 曹淑云[1] 李孝文 田韵 刘忠 范建伟 王淑婷 LI Qing-song;CAO Shu-yun;LI Xiao-wen;TIAN Yun;LIU Zhong;FAN Jian-wei;WANG Shu-ting(State Key Laboratory of Geological Processes and Mineral Resources,School of Earth Sciences,China University of Geosciences,Wuhan 430074,China;School of Architectural Engineering,Tongling College,Tongling 244061,China)

机构地区：[1]中国地质大学(武汉)地球科学学院,地质过程与矿产资源国家重点实验室,湖北武汉430074 [2]铜陵学院建筑工程学院,安徽铜陵244061

出　　处：《岩石矿物学杂志》2025年第2期259-282,共24页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金项目(42320104007,41972220,42302262,42202229)。

摘　　要：绿柱石是重要的铍铝硅酸盐矿物,具有极高的经济和工业价值。老君山片麻岩穹窿位于华南陆块与印支陆块的结合部位,经历了多期构造-岩浆作用,并发育有锡、铜、锌等多金属矿床与祖母绿矿床。本研究重点针对区域中出露的绿柱石及其共生石英脉开展了详细的宏观与微观构造特征分析,并结合流体包裹体与石英EBSD组构开展了形成与变形温度环境限定。研究结果表明,绿柱石与石英中都保存有丰富的流体包裹体,其中绿柱石中存在低温-高盐度两相与高温-低盐度三相流体包裹体类型,石英中存在低温-低盐度两相流体包裹体类型。绿柱石石英脉中的石英变形特征主要为发育底面滑移系叠加次要的柱面<c>滑移系,指示低温(约350~400℃)为主的变形环境,局部叠加相对高温变形。燕山中晚期的岩浆流体伴随片麻岩穹窿隆升/剥露,带来了丰富的成矿元素,其中包括绿柱石成矿所需的主要Be元素。区域片麻岩穹隆从深部至浅部的剥露过程为成矿作用提供了重要的构造容矿流体通道,伴随流体不混溶现象的出现,成矿流体pH值增高,进而促进成矿元素赋存沉淀。Beryl is an important Be-Al silicate mineral with high economic and industrial value.Laojunshan gneiss dome is located in the joint of South China block and Indosinian block,which has experienced multi-stage tectonic-magmatic action and developed Sn,Cu,Zn and other polymetallic deposits and emerald deposits.This study focuses on the detailed analysis of macro-and micro-structural characteristics of beryl and its symbiotic quartz veins in the region,and limits the temperature environment of formation and deformation through fluid inclusions and quartz EBSD fabric.The results show that beryl and quartz are rich in fluid inclusions,in which beryl has low temperature-high salinity two-phase and high temperature-low salinity three-phase fluid inclusions,and quartz has low temperature-low salinity two-phase fluid inclusions.The deformation characteristics of the quartz associated with beryl mainly develop rhombal superimposed by secondary prim,indicating low-temperture(350~400℃)deformation environment,superimposed by local high-temperture deformation.The magmatic fluid in the middle and late Yanshanian was accompanied by the uplift/exhumation of gneiss dome,which brought rich ore-forming elements,including the main Be elements of beryl mineralization.The exhumation process of regional gneiss dome from deep to shallow provides an important structural ore-bearing fluid channel for mineralization.With the occurrence of fluid immiscibility,the pH value of ore-forming fluid increases,thus promoting the occurrence and precipitation of ore-forming elements.

关 键 词：绿柱石 流体包裹体 显微观测 变形EBSD组构 流体不混溶作用 

分 类 号：P315.23[天文地球—地震学] P578.953[天文地球—固体地球物理学]