滇西维西县铜厂箐铜矿床C-O-H同位素特征及其成因探讨  

C-O-H Isotopic Composition and Genesis of the Tongchangqing Copper Deposit in the Lanping Basin,Weixi County,Western Yunnan

作　　者：沙建泽 王涛 徐荣[3] 邓明国[3] 孙涛 燕利军[1,2] SHA Jianze;WANG Tao;XU Rong;DENG Mingguo;SUN Tao;YAN Lijun(Yunnan Institute of Geological Survey,Kunming,Yunnan 650216;MLR Key Laboratory of Sanjiang Metallogeny&Resources Exploration and Utilization,Kunming,Yunnan 650051;Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming,Yunnan 650093;School of Earth Science,Yunnan University,Kunming,Yunnan650500)

机构地区：[1]云南省地质调查院,云南昆明650216 [2]自然资源部三江成矿作用及资源利用重点实验室,云南昆明650051 [3]昆明理工大学国土资源工程学院,云南昆明650093 [4]云南大学地球科学学院,云南昆明650500

出　　处：《地质与勘探》2021年第4期910-919,共10页Geology and Exploration

基　　金：国家自然科学基金项目(编号:41363001)资助。

摘　　要：滇西维西县铜厂箐铜矿床赋存于中侏罗统花开佐组二段粉砂质泥岩、粉砂岩夹泥灰岩中,受断裂构造控制呈脉状产出。本次通过研究与该矿床铜矿化关系密切的石英及方解石C-H-O同位素组成特征,揭示其成矿流体来源,进而探讨该矿床成因。研究发现,该矿床中主成矿阶段与铜矿共生的方解石样品的δ13 C V-PDB值变化于-6.93‰~-6.16‰,均值为-6.69‰,δ18 O V-SMOW值变化于10.88‰~13.07‰,均值为11.98‰;与铜矿共生的石英样品的δ18 O V-SMOW值变化于14.22‰~16.88‰,均值为15.93‰,δD V-SMOW值介于-87.0‰~-61.7‰,均值为-75.99‰,表明成矿流体主要源自岩浆水。结合区域地质背景,认为在喜马拉雅期印度-欧亚大陆碰撞背景下,由于澜沧江深大断裂和雪龙山断裂长期活动,伴有深部岩浆含矿热液沿构造裂隙充填,形成铜厂箐脉状铜矿床。The Tongchangqing copper deposit in the Lanping Basin,Weixi County,western Yunnan is a vein-type Cu deposit controlled by faults,which occurs in silty mudstone,siltstone and muddy limestone of the second member of Middle Jurassic Huakaizuo Formation.This work analyzed the isotopic composition of quartz and calcite which are closely related to copper mineralization in this deposit,determined the source of ore-forming fluid and discussed the genesis of the deposit.Analysis data show that the syn-ore calcite hasδ13 C PDB andδ18 O SMOW values of-6.93‰to-6.16‰(-6.69‰on average)and 10.88‰to 13.07‰(11.98‰on average),respectively.δD H 2O values of the fluid inclusions in the syn-ore quartz range from-87.0‰to-61.7‰(-75.99‰on average),andδ18 O H 2O values of the syn-ore quartz are of 5.25‰to 7.91‰(6.96‰on average).These C-O-H isotopic compositions indicate that the ore-forming fluid originated from magmatic water.Considering the regional geology,this study suggests that the genesis of this deposit is associated with the India-Eurasia continental collision during the Himalayan period.In such a tectonic setting,the long-term activity of the Lancangjiang and Xuelongshan faults,accompanied with ore-bearing hydrothermal fluids from deep magma filling structural cracks,resulted in the Tongchangqing vein-type Cu deposit.

关 键 词：C-H-O同位素 流体来源 矿床成因 铜厂箐铜矿床 维西县 滇西 

分 类 号：P618.65[天文地球—矿床学] P597[天文地球—地质学]