内蒙古香林香达铜矿区火山-侵入杂岩地球化学特征及年代学研究  

Geochemical characteristics and chronology of volcanic-intrusive complex in Xianglinxiangda Cu deposit,Inner Mongolia

作　　者：孙连宇 刘继顺[1,3,4] SUN Lianyu;LIU Jishun(School of Geosciences and Info-Physics,Central South University,Changsha 410083,Hunan,China;Hunan Kexin Electric Power Design Co.,Ltd.,Changsha 410007,Hunan,China;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Ministry of Education,Central South University,Changsha 410083,Hunan,China;Hunan Key Laboratory of Nonferrous Resources and Geological Hazards Exploration,Changsha 410083,Hunan,China)

机构地区：[1]中南大学地球科学与信息物理学院,湖南长沙410083 [2]湖南科鑫电力设计有限公司,湖南长沙410007 [3]中南大学有色金属成矿预测与地质环境监测教育部重点实验室,湖南长沙410083 [4]有色资源与地质灾害探查湖南省重点实验室,湖南长沙410083

出　　处：《矿产与地质》2019年第4期650-659,共10页Mineral Resources and Geology

摘　　要：香林香达铜矿区位于华北大陆北缘白乃庙弧中部。以矿区内广泛分布的含矿火山-侵入杂岩为研究对象,从野外地质特征、岩石学特征、岩石地球化学特征以及锆石U-Pb年龄等方面对岩石成因、构造环境、形成时代以及接触关系进行了系统的探讨。研究结果表明:香林香达矿区含矿黑云母石英闪长岩锆石U-Pb年龄为(250.9±2.1)Ma,与安山质火山-沉积岩呈侵入接触关系。岩石属钙碱性-高钾钙碱性系列,具准铝质、低K高Na等特征;稀土元素配分模式表现为轻稀土富集型的右倾曲线,具弱的负Eu异常;微量元素特征显示富集大离子亲石元素Rb、Ba、K,亏损高场强元素Nb、Ta、P、Ti。香林香达矿区火山-侵入杂岩地球化学特征表明,原始岩浆应来源于受俯冲洋壳流体交代的楔形地幔区,在喷发与侵入过程中,混染了地壳物质,具有壳幔混源成因特征,形成于洋壳俯冲火山弧构造环境。Xianglinxiangda Cu mining area is located in the middle of Bainaimiao arc on the northern margin of North China continent.Focusing on the ore-bearing volcanic-intrusive complex widely distributed in the mining area,this paper systematically discusses the rock genesis,tectonic environment,formation age and contact relationship from the aspects of field geology,petrology,geochemistry and zircon U-Pb dating.The results of the study showed that the zircon U-Pb age of ore-bearing biotite quartz diorite in Xianglinxiangda mining area is(250.9±2.1)Ma,which is intrusive contact with andesite volcanic-sedimentary rocks.The rocks are characterized by calc-alkalinity-high potassium calc-alkalinity,quasi-alumina,low K and high Na.The distribution pattern of REE shows a right-leaning curve of light rare earth enrichment type with weak negative Eu anomaly and the trace elements show enrichment of large ion lithophile elements Rb,Ba,K and depletion of high field strength elements Nb,Ta,P and Ti.The geochemical characteristics of the volcanic-intrusive complex in Xianglinxiangda mining area indicate that the original magma originated from the wedge-shaped mantle area which is metasomatized by subduction oceanic crust fluid.During the process of eruption and intrusion,it mixed with crustal material and had the characteristics of crust-mantle mixed origin,forming in the tectonic environment of oceanic crust subduction volcanic arc.

关 键 词：香林香达铜矿区 火山-侵入杂岩 岩石地球化学特征 锆石U-PB年龄 岩石成因 接触关系 

分 类 号：P597[天文地球—地球化学] P618.41[天文地球—地质学]