地质通报2025，Vol.44Issue(4)：679-704,26.DOI:10.12097/gbc.2024.05.047
东昆仑清水河东沟斑岩型钼矿床含矿岩体年龄、地球化学特征及其对成矿机制的约束
Zircon U-Pb ages,geochemical characteristics and their constraints on metallogenic mechanism of ore-bearing porphyry in Qingshuihe Donggou molybdenum deposit,East Kunlun
摘要
Abstract
[Objective]The Qingshuihe Donggou porphyry molybdenum deposit is one of the representative porphyry deposits in the East Kunlun metallogenic belt.[Methods]Therefore,a detailed study of the age,genesis and tectonic environment of the porphyry intrusions in the Qingshuihe Donggou deposit is needed to improve the understanding of the metallogenic regularity of this area.In this paper,zircon U-Pb dating,petrogeochemistry and zircon Hf isotope of the porphyries from the Qingshuihe Donggou deposit,which are closely related to the Mo mineralization,have been studied.[Results]The zircon U-Pb age of granodiorite porphyry is 226.9±1.3 Ma(MSWD=1.03,n=18),and the zircon U-Pb age of diorite porphyry is 224.3±1.2 Ma(MSWD=0.47,n=15),These results indicate that this deposit formed at 226.9～224.3 Ma.Granodiorite porphyry,diorite porphyry and granite porphyry are rich in Si,Na,K and Al,poor in Ti and Mg,and show a right-leaning partition pattern characterized by the light rare earth element enrichment.The former two granites have no obvious Eu depletion(δEu:0.79～0.98),whereas granite porphyry displays noticeable Eu depletion(δEu:0.22～0.24).All of them are enriched in large ion lithophile elements(e.g.,Rb,K,Ba),and depleted in high field strength elements(e.g.,Ta,Nb,Ti,P),belonging to the metalluminous to weak peraluminous high K calc-alkaline granites.The 176Hf/177Hf ratio of zircon from these porphyry rocks ranges from 0.282510 to 0.282652,the εHf(t)value ranges from-4.5 to 0.2,and the two-stage model age ranges from 1541 Ma to 1240 Ma.[Conclusions]Based on the characteristics of regional tectonic evolution,it is deduced that these porphyries formed by partial melting of the Middle Proterozoic Jinshuikou Group under the Late Triassic post-collisional extension environment,and experienced magma mixing by mantle-derived materials.关键词
斑岩钼矿/锆石U-Pb定年/地球化学/花岗闪长斑岩/清水河东沟/东昆仑Key words
porphyry molybdenum deposit/zircon U-Pb age/geochemistry/granodiorite porphyry/Qingshuihe Donggou/East Kunlun分类
地质学引用本文复制引用
张勇,马忠元,李小伟,奎明娟,刘智刚,莫生娟..东昆仑清水河东沟斑岩型钼矿床含矿岩体年龄、地球化学特征及其对成矿机制的约束[J].地质通报,2025,44(4):679-704,26.基金项目
青海省第三地质勘查院项目《东昆仑斑岩成矿系统研究》(编号:SKYZC-2022-007)、青海省地质矿产勘查开发局项目《柴周缘钴镍成矿规律及靶区优选》(批准号:青地矿科[2023]79号)、青海省高端创新创业人才计划项目《东昆仑热水喷流沉积型钴矿成矿模式及靶区优选》(批准号:青地矿科[2022]32号)和青海省自然资源厅项目《青海省祁漫塔格地区铜镍钴矿找矿突破研究》(编号:2024524028ky002) （编号:SKYZC-2022-007）
