广西中酸性岩浆岩风化区风化矿床类型及成矿作用研究  

Classification and Mineralization of Intermediate-Acid Magmatic Rocks-Related Weathering Deposits in Guangxi

作　　者：万宏宇 付伟[1,2] 罗鹏 王新宇 覃定量 李春平 高山 WAN Hongyu;FU Wei;LUO Peng;WANG Xinyu;QIN Dingliang;LI Chunping;GAO Shan(Department of Earth Sciences,Guilin University of Technology,Guilin,Guangxi 541004;Collaborative Innovation Center for Exploration of Hidden Nonferrous Metal Deposits and Development of New Materials in Guangxi,Guilin University of Technology,Guilin,Guangxi 541004;Department of Land and Resources of Guangxi Zhuang Autonomous Region,Nanning,Guangxi530028;Guangxi Bureau of Geology&Mineral Prospecting&Exploitation,Nanning,Guangxi530023)

机构地区：[1]桂林理工大学地球科学学院,广西桂林541004 [2]广西有色金属隐伏矿床勘查及材料开发协同创新中心,桂林理工大学,广西桂林541004 [3]广西壮族自治区自然资源厅,广西南宁530028 [4]广西地质矿产勘查开发局,广西南宁530023

出　　处：《地质与勘探》2020年第1期1-16,共16页Geology and Exploration

基　　金：国家自然科学基金重大研究计划项目(编号:91962107);广西自然科学基金(编号:2014GXNSFAA118304);广西高校重点实验室基金(编号:桂科隐12-A-02-01、桂科能15-140-27-10);广西地质矿产勘查开发局部门预算前期工作经费项目(编号:桂地矿综研[2018]20号)联合资助

摘　　要：广西区内139个主要风化矿床(点)中有近4成集中分布于中酸性岩浆岩风化区。新近纪以来新构造运动活跃,东亚季风盛行产生了湿热气候,致使近2.0×105 km 2不同时代、不同岩性的中酸性岩浆岩广泛出露并遭受强烈风化,大面积的厚层风化壳在低山丘陵地貌景观区得以保存,这为风化矿床的发育提供了得天独厚的气候、地质、构造和地貌等条件。广西中酸性岩浆岩风化作用形成的矿床主要包括残积型(以钛铁砂矿为代表)、淋积型(以离子吸附型稀土矿为代表)和残余型(以高岭土矿和膨润土矿为代表)三个类型。这些不同类型的风化矿床在成矿条件上表现出显著的母岩专属性和风化环境偏在性,二者联合约束了风化矿床的成矿作用及成矿类型。风化过程中复杂的水岩反应(淋积作用、残积作用和残余作用)是导致中酸性岩浆岩风化形成各类矿床的内在机制。Guangxi hosts many weathering deposits characterized by wide distribution,diverse types,large scales and good ore quality which are rare in China and elsewhere in the world.The weathering mineral resources,including aluminum,manganese and rare earth,are regarded as a“name-card”of Guangxi.Statistics show nearly 40%of 139 known weathering deposits in Guangxi are distributed in areas with exposed intermediate-acid magmatic rocks,implying a special geologic setting.Data suggests that since the Neogene Guangxi has been subject to hot and humid climate associated with the East Asian monsoon.Coupled with active neotectonic movement,such a climate condition resulted in nearly 2.0×105 km 2 of strongly weathered intermediate-acid magmatic rocks.Thick regolith derived from weathering of these rocks is widely distributed,which offers a unique condition for supergene mineralization.The intermediate-acid magmatic rock weathering deposits in Guangxi can be divided into three major types:placer type(represented by ilmenite ore deposit),illuviation type(represented by ion-adsorption REE deposit)and residual type(represented by kaolin deposit).In terms of ore-controlling factors,the mineralization specificity of the parent rocks is as important as the local weathering environments,which jointly constrained the genesis of the weathering deposits.The complex water-rock reactions(e.g.,leaching,ion-exchange,and elution)during the rock weathering are the intrinsic mechanisms for the diversity of the weathering mineralization.

关 键 词：中酸性岩浆岩 风化成矿作用 风化矿床 广西 

分 类 号：P612[天文地球—矿床学]