滇西北松诺斑岩体岩石化学、锆石U-Pb年龄、Hf同位素特征及其构造背景  

Petrochemical,Zircon U-Pb age and Hf Isotopic Characteristics of the Songnuo Porphyry in Northwestern Yunnan and Their Geological Significance

作　　者：王浩[1,2] 余海军 张传昱 王路 苏肖宇 江佳雯 WANG Hao;YU Haijun;ZHANG Chuanyu;WANG Lu;SU Xiaoyu;JIANG Jiawen(Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming 650093,Yunnan,China;MNR Key Laboratory of Sanjiang Metallogeny and Resources Exploration and Utilization,MNR,Kunming 650051,Yunnan,China;Yunnan Geological Survey,Kunming 650216,Yunnan,China;Yunnan Key Laboratory of Sanjiang Metallogeny and Resources Exploration and Utilization,Kunming 650051,Yunnan,China;Faculty of Earth Resource,China University of Geosciences(Wuhan),Wuhan 430074,Hubei,China)

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650093 [2]自然资源部三江成矿作用及资源勘查利用重点实验室,云南昆明650051 [3]云南省地质调查院,云南昆明650216 [4]云南省三江成矿作用及资源勘查利用重点实验室,云南昆明650051 [5]中国地质大学(武汉)资源学院,湖北武汉430074

出　　处：《大地构造与成矿学》2023年第5期1040-1062,共23页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(42173026);云南省基础研究计划专项面上项目(202301AT070019);云南省科技计划项目(202305AT350004-3);云南省“兴滇英才”青年人才项目联合资助。

摘　　要：近年来,随着普朗和红山-红牛等大型-超大型铜矿的投产,滇西北格咱地区已成为我国重要的铜资源勘查开发基地,在该区寻找类似“普朗-红山式”斑岩-矽卡岩型大型-超大型铜多金属矿床是本区找矿勘查的热点。本次在开展松诺地区铜资源远景调查的基础上,对松诺含矿石英闪长玢岩开展了锆石U-Pb年代学研究,结果显示石英闪长玢岩体锆石U-Pb年龄分别为229.7±1.1Ma和222.3±0.7Ma,早于矿区石英二长斑岩体,为晚三叠世岩浆活动的产物。石英闪长玢岩和石英二长斑岩岩石地球化学特征显示,为准铝-弱过铝质的高钾钙碱性系列I型花岗岩,稀土元素配分曲线均表现为轻稀土元素富集,重稀土元素相对亏损,具弱的负Eu异常,富集Rb、Ba等大离子亲石元素,亏损Ta、Nb、Ti等高场强元素。综合岩相学、岩石化学、锆石Hf同位素和全岩Sr-Pb同位素等特征,认为松诺含矿斑岩体形成于印支期甘孜-理塘洋壳向西俯冲的岩浆弧环境,岩浆源区为俯冲流体交代的岩石圈富集地幔,岩浆上升过程经历了壳源沉积物质混染。矿区具备弧环境斑岩型铜多金属矿床的成矿条件,且蚀变矿化强烈,找矿前景良好,值得进一步深入研究和开展勘查工作。In recent years,with the built of large and super-large copper deposits such as Pulang and Hongshan-Hongniu,the Geza area in Northwest Yunnan has become an important porphyry copper ore concentration area and copper resource exploration and development base in China,and searching for the“Pulang-Hongshan style”porphyry-skarn type large and super-large copper polymetallic deposits in this area has become a hot spot of ore geological study and prospecting exploration.Based on the prospective survey of copper resources in the Songnuo area,petrological and geochemical investigations were carried out on the mineralized quartz diorite porphyrite in the Songnuo area.Two samples of ore-bearing quartz diorite porphyrites at Songnuo have zircon U-Pb ages of 229.7±1.1 Ma and 222.3±0.7 Ma,respectively,indicating that they are the products of the Late Triassic magmatic activity.The quartz diorite porphyrite and quartz monzonite porphyry show the petrochemical characteristics of pseudoaluminous-weak peraluminous shoshonite-high-potassium calc-alkaline series I-type granite.The rocks show REE patterns characterized by LREE enrichment,relatively depletion of HREE,weak negative Eu anomalies,whereas their trace elements are featured by enrichment of large ion lithophile elements such as K,Rb and Ba,and depletion of high field strength elements such as Ta,Nb,P and Ti.Based on the characteristics of petrology,rock geochemistry,zircon Hf isotope and whole rock Sr-Pb isotopes,it is considered that the Songnuo ore-bearing porphyry was formed in the arc tectonic environment formed by the westward subduction of the Ganzi-Litang oceanic crust during the Indosinian period.The magma source is the enriched lithosphere mantle metasomatized by subducting related fluids,and during ascending process,the magma experienced contamination by crust-derived sedimentary materials.Thus,the pluton has metallogenic conditions of island arc porphyry copper polymetallic deposits,showing strong alteration and mineralization and promising prospecting pot

关 键 词：锆石U-Pb年代学 HF同位素 岩相学 松诺铜矿床 滇西北 

分 类 号：P581[天文地球—岩石学] P595[天文地球—地质学] P597