赣西北地区大湖塘钨多金属矿集区隐爆角砾岩成因机制及其成矿意义  

Petrogenesis and Metallogenic Significance of Cryptoexplosive Breccia in the Dahutang Tungsten Polymetallic Orefield,Northwest Jiangxi Province

作　　者：李梦静 黄小龙[1,2] 孙德明 于洋[1,2] 张馨文[1,2,3] LI Mengjing;HUANG Xiaolong;SUN Deming;YU Yang;ZHANG Xinwen(State Key Laboratory of Deep Earth Processes and Resources,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;Center of Excellence of Deep Earth Sciences,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China;The Third Geological Brigade of Jiangxi Geological Bureau,Jiujiang 332100,Jiangxi,China)

机构地区：[1]中国科学院广州地球化学研究所,深地过程与战略矿产资源全国重点实验室,广东广州510640 [2]中国科学院深地科学卓越创新中心,广东广州510640 [3]中国科学院大学,北京100049 [4]江西省地质局第三地质大队,江西九江332100

出　　处：《大地构造与成矿学》2025年第2期335-350,共16页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(42330305);中国科学院广州地球化学研究所所长基金(2022SZJJZD-02)联合资助。

摘　　要：隐爆角砾岩是岩浆在近地表处隐蔽爆破形成的一类特殊构造岩石,是钨锡多金属矿床的重要找矿标志之一,同时也是金、铜、钨、钼、铀等矿产的重要赋存类型。赣西北地区大湖塘钨多金属矿集区地处九岭成矿带,赋存世界级超大型钨矿床。其中,石门寺隐爆角砾岩型钨铜钼矿作为该矿集区的重要矿体,是典型的伴生型隐爆角砾岩矿床。本研究通过系统的野外地质调查与岩相学观察,结合前人研究成果,揭示了石门寺隐爆角砾岩具有显著的分带特征:角砾岩由小块状岩石角砾与胶结物混杂构成,自矿体中心向边部,角砾粒度呈现由小变大的趋势,胶结物脉宽则逐渐减小并充填于围岩裂隙中。研究表明,石门寺隐爆角砾岩的形成主要受岩浆‒气液爆破作用控制,其角砾岩筒的形态特征及角砾与胶结物的组成明显区别于断裂构造形成的构造角砾岩。研究区圈闭的围岩条件、持续的岩浆活动、深大断裂构造以及大气降水的参与是隐爆作用发生的关键控制因素。隐爆作用导致围岩(晋宁期花岗岩)产生大量裂隙,为后期含矿岩浆热液与大气降水热液的运移、交代、混合以及矿质卸载、沉淀提供了有利的构造空间。因此,隐爆作用不仅改变了成矿环境,而且还是同一矿区发育多种类型矿体的重要控制因素,对大湖塘超大型钨多金属矿床的形成具有重要的地质意义。Cryptoexplosive breccias formed through concealed magmatic explosions in subvolcanic environments exhibit distinctive structural characteristics that serve as indicators of tungsten-tin polymetallic deposit exploration.These breccia-associated deposits represent a significant mineralization type for various metallic elements,including Au,Cu,W,Mo,and U.The Dahutang tungsten polymetallic orefield,situated in northwestern Jiangxi province within the Jiuling metallogenic belt of South China,hosts a globally significant super-large tungsten deposit.The Shimensi deposit,characterized by its cryptoexplosive breccia-type W-Cu-Mo mineralization,serves as a representative example of this deposit type.Through comprehensive field investigations,petrographic analyses,and the synthesis of existing data,this study elucidates the zonation characteristics of the Shimensi cryptoexplosive breccia within the Dahutang polymetallic orefield.The breccia formation primarily involved the amalgamation of small blocky fragments with cementing materials,exhibiting a gradual increase in grain size from the central orebody toward the periphery.Concurrently,the width of the cement veins diminishes as the fractures in the surrounding rocks infill.The breccia genesis is attributed to phreatomagmatic explosions,which are distinguishable from tectonic breccias through their characteristic cryptoexplosive breccia pipe morphology and distinctive breccia and cement features.The formation of cryptoexplosives depends on several critical factors,including the trap conditions,sustained magmatic activity,major fault systems,and meteoric water interaction.The cryptoexplosive process generates extensive fracture networks within wallrocks(Neoproterozoic Jiuling granodiorite batholith),creating favorable structural conduits for subsequent magmatic hydrothermal fluid migration,mixing with meteoric water,and ore precipitation.Consequently,the alteration of the ore-forming environment induced by cryptoexplosive activity constitutes the primary factor governing t

关 键 词：钨多金属矿 隐爆作用 隐爆角砾岩型矿床 花岗岩 大湖塘 

分 类 号：P581[天文地球—岩石学] P611[天文地球—地质学]