地质通报2024，Vol.43Issue(7)：1133-1148,16.DOI:10.12097/gbc.2022.10.027
东昆仑库德尔特金多金属矿床闪长玢岩年龄、地球化学特征及形成环境
Age,geochemistry and formation environment of diorite porphyrite in Kudeerte gold-polymetallic deposit,East Kunlun
摘要
Abstract
In order to determine the metallogenic age and tectonic environment of the Kudeerte gold-polymetallic deposit in Kaerqueka ore field,this work studies on zircon U-Pb isotopic dating and whole rock geochemical analysis of diorite porphyrite.The results indicated that the zircon U-Pb weighted average age of diorite porphyrite is 232.6±1 Ma(MSWD=0.17),which is slightly later than the granodiorite age(244～234.1 Ma)and Ar-Ar plateau age(236.7±4.0 Ma)of gold mineralization sericite,limiting the upper age of gold mineralization to no later than 233 Ma.The dioritie porphyrite has SiO2 ranges from 54.96%to 55.57%,rich in Al(17.94%to 18.07%,Al2O3),and high in Sr(455×10-6～505×10-6),low Y(19.2×10-6～26.4×10-6)and Yb(2.18×10-6～2.95×10-6).A/CNK ratios range from 0.87 to 0.89,and belong to high potassium calc-alkaline sub-aluminum series.The fractionation of light and high rare earth elements(LREEs and HREEs)is obvious,and the LREEs are enriched.The LREE/HREE ratios range from 6.24 to 8.69,and the(La/Yb)N ratios from 7.25 to 10.36,and the Eu is medium deficit.Enrichment of large-ion lithophile elements(LILEs),such as Rb,Th,U,K,etc.,and depletion of high-field strength elements(HFSEs),such as Nb,Ta,P and Ti.It has high Sr/Yb ratios of 154.24 to 216.74,Sr/Y ratios of 17.23 to 24.27,Nb/Ta ratios of 17.79 to 20.05,Mg#values of 49.35 to 50.18,and Rb/Sr ratios of 0.27 to 0.3,in the range of 0.05 to 0.5.Based on the regional geological background and metallogenic characteristics,it is believed that the diorite porphyrite was formed in the partial melting of the mesoproterozoic lower crust during the subduction-collision transition tectonic stage of mantle source magma,and the East Kunlun area was in an extended environment influenced by subduction plate fragmentation during the Middle-Late Triassic subduction-collision transition,which is obviously different from the typical compressional orogenic belt.The strong crust-mantle interaction promotes the concentrated production of deposits in the area.关键词
年代学/地球化学/构造环境/闪长玢岩/库德尔特/金多金属矿床/东昆仑Key words
chronology/geochemistry/tectonic setting/diorite porphyrite/Kudeerte/gold-polymetallic deposit/Eastern Kunlun分类
地质学引用本文复制引用
刘光莲,汪周鑫,张大明,张勇,刘智刚,马忠元..东昆仑库德尔特金多金属矿床闪长玢岩年龄、地球化学特征及形成环境[J].地质通报,2024,43(7):1133-1148,16.基金项目
科技部国家重点研发计划项目课题《热液型矿床钴成矿作用与找矿勘查》(编号:2022YFC2903503)、国家自然科学基金重大研究计划项目《柴北缘花岗伟晶岩型锂铍等关键金属超常富集成矿的可能机制》(编号:92062217)和青海省"高端创新创业人才"计划项目《青海省东昆仑地区榴辉岩与成矿耦合关系研究》(编号:青地矿科[2021]61号) （编号:2022YFC2903503）
