老挝班康姆铜金矿床“岩浆核杂岩”隆起-拆离带构造控矿特征  

Ore-controlling Structural Characteristics of the Bankangmu Copper-Gold Depositin Laos:Magmatic Core Complex Uplift-Detachment Zone

作　　者：赵俊宏 杨人毅 吕古贤[2] 赵延朋 康铁锁 陈晓峰 ZHAO Junhong;YANG Renyi;LYU Guxian;ZHAO Yanpeng;KANG Tiesuo;CHEN Xiaofeng(China Nonferrous Metals Guilin Institute of Mineral Geology Co,Ltd,Guilin,Guangxi541000,China;Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing100081,China)

机构地区：[1]中国有色桂林矿产地质研究院有限公司,广西桂林541000 [2]中国地质科学院地质力学研究所,北京100081

出　　处：《现代地质》2024年第4期1067-1075,共9页Geoscience

基　　金：中国有色集团科技计划项目“中国有色矿业集团矿山资源现状调查与找矿潜力分析”(2019KJJH02);国家重点研发计划项目“钴镍成矿规律与高效勘查技术示范研究”之专题“东南亚红土型钴镍矿成矿作用与找矿勘查”(2022YFC2903502);中国有色集团科技计划项目“东南亚离子吸附型中重稀土矿床成矿规律与找矿潜力研究”(2022KJJH02)。

摘　　要：老挝班康姆铜金矿床位于东南亚思茅—彭世洛地块南缘构造活跃带,是与中生代岩浆岩有关的大型铜金矿床。该区具有巨大的资源潜力,但地质研究程度相对较低,其成矿模式和演化规律等理论问题尚未完全解决。本文通过对成矿岩体分布特征、断裂构造变形特征和拆离带构造成矿特征的研究,揭示矿床岩浆核杂岩隆起特征与拆离带构造特征,认为班康姆矿床受控于“岩浆核杂岩”及其边界的隆起-拆离带构造,为岩浆核杂岩隆起-拆离带构造热液铜金矿床。班康姆矿床“岩浆核杂岩”构造由“岩浆杂岩体核、拆离带构造和火山-沉积岩”三个部分组成,岩浆杂岩体核主要由花岗闪长岩组成。花岗闪长岩与安山岩和灰岩接触带下盘发育有似片麻理构造,片理产状以核部花岗闪长岩为中心,呈现外倾的特征,推断为岩浆岩上侵过程中受到区域挤压剪切应力的作用形成。磁法和激电测量结果,反映班康姆矿床矿化蚀变带和岩浆核杂岩的分布关系,结合地质实测的岩体分布信息,推测深部存在隐伏岩体。拆离带构造发育于下盘花岗闪长岩体与上盘火山-沉积岩之间,是铜金矿化的集中地段,且拆离带构造中矿化蚀变岩的形成年龄(244~251 Ma),晚于杂岩体侵位年龄(264±10 Ma)。通过对拆离带构造及两侧小型构造观测与分析,可知拆离带构造剖面上呈上陡下缓的“铲”式形态学特征,具有明显的早期韧性变形、晚期脆性变形的特点,其上盘的主运动方向为NWW向。本文提出班康姆铜金矿床的东南部同样具有“岩浆核杂岩”隆起-拆离带构造成矿模式的特征,为有利的找矿靶区。The Bankangmu copper-gold deposit,located in the tectonically active zone at the southern margin of the Simao-Phetchabun block in Southeast Asia,is a large copper-gold deposit associated with Mesozoic mag-matism.Despite the significant resource potential of this area,some key geological questions remain unre-solved,such as those related to ore-forming models and evolutionary processes.This paper investigates the dis-tributions of ore-forming intrusions,fault structure deformation features,and ore-forming characteristics within the detachment zone to reveal the uplift features of the magmatic core complex and the structural characteristics of the deposit in this zone.This study posits that the Bankangmu deposit is controlled by the structure of the“magmatic core complex”and its boundaries within the uplift-detachment zone,categorizing it as a hydrother-mal copper-gold deposit formed in this magmatic core complex uplift-detachment zone.The magmatic core com-plex structure of the Bankangmu deposit consists of three parts:the magmatic complex core,the detachment zone structure,and the volcanic-sedimentary rocks.The magmatic complex core is mainly composed of grano-diorite.At the contact zone between the granodiorite-andesite and limestone in the footwall,a gneiss-like tex-ture has developed.The foliation,centered on the core granodiorite,exhibits an outward dip and is inferred to have formed under regional compressive shear stress during the magmatic intrusion processes.Magnetic and in-duced polarization measurements reveal the relationship between the mineralized zone and the magmatic core com-plex in the Bangkangmu deposit.Combined with geological survey data on the distribution of intrusions,we sug-gest that there is a concealed intrusion deeper whithin the structure.The detachment zone structure,developed between the footwall granodiorite and the hanging wall volcanic-sedimentary rocks,is the focal area for copper-gold mineralization.The formation age of the mineralized alteration rocks in the detachment zone

关 键 词：班康姆铜金矿床 岩浆核杂岩隆起 拆离带构造 成矿特征 

分 类 号：P54[天文地球—构造地质学] P588.1[天文地球—地质学] P618.41P618.5