地球学报2024，Vol.45Issue(4)：515-529,15.DOI:10.3975/cagsb.2024.042401
扬子西缘东炉房Cu-Mo矿床侵入岩年代学、地球化学特征及其成矿意义
Geochronology and Whole-rock Geochemistry of Intrusive Rocks from the Donglufang Cu-Mo Deposit in Western Margin of the Yangtze Block and Their Metallogenic Implications
摘要
Abstract
The Donglufang Cu-Mo deposit is located in the western margin of the Yangtze Block.The deposit is characterized by porphyry Mo(-Cu)orebodies associated with quartz monzonite porphyry and skarn Cu orebodies.While previous research has mainly focused on the genesis of porphyry Mo mineralization,research on skarn Cu mineralization is relatively weak.In this paper,the zircon U-Pb geochronology and whole-rock geochemistry of Cu-mineralized quartz diorite porphyrite are studied on the basis of investigations of the exploration results of the deposit.The results show that the zircon U-Pb weighted average age of quartz diorite porphyrite is 82 Ma,indicating that it was formed in the Late Cretaceous,which is consistent with the W-Mo(Cu)mineralization age of the Late Cretaceous in the Geza arc.Quartz diorite porphyrite are high silica(SiO2=60.74%-63.36%),alkali-rich(Na2O+K2O=7.03%-9.29%),metaluminous(A/CNK=0.63-0.86),displaying shoshonitic I-type granite characteristics.The rare earth elements have obvious right-leaning patterns and typical adakite affinity characteristics,which can be interpreted as the product of partial melting of the intermediate-mafic lower crust mix with mantle-derived magma.The nature of the magmatic source and the type of wall rocks determine the mineralization zoning of the Donglufang Deposit,with porphyry Mo(-Cu)mineralization occurring in the potassic zone of the deep quartz monzogranite porphyry,skarn Cu(-Mo)mineralization occurring in the contact zone,and vein Pb-Zn-Au-Ag mineralization occurring in the peripheral marble.The deposit constitutes a porphyry mineralization system with Mo(-Cu),Cu(-Mo),and Pb-Zn-Au-Ag mineralization.Our comparative study shows that the Late Cretaceous magmatic rocks and related mineralization in Geza arc extend southward to the western margin of Yangze Block,formed in the post-collision extensional setting.The degree of magmatic differentiation gradually decreases from north to south,and the contribution of mantle-derived magma gradually increased,resulting in obvious different mineralization style from north to south,i.e.,from northern Xiuwacu W-Mo,Relin Mo-W,Hongshan and Tongchanggou Mo(-Cu),to southernmost Donglufang Cu(-Mo).关键词
石英闪长玢岩/U-Pb年代学/地球化学/晚白垩世/东炉房/扬子西缘Key words
quartz diorite porphyrite/U-Pb geochronology/geochemistry/Late Cretaceous/Donglufang/the western margin of Yangtze Block分类
天文与地球科学引用本文复制引用
段召艳,张有名,杨新强,杜斌,伍建兢,杨富成,江小均..扬子西缘东炉房Cu-Mo矿床侵入岩年代学、地球化学特征及其成矿意义[J].地球学报,2024,45(4):515-529,15.基金项目
本文由云南省科技计划项目高层次科技人才及创新团队选拔专项(编号:202305AT350004)资助. This study was supported by Science and Tech-nology Plan Project of Yunnan Province(No.202305AT350004). （编号:202305AT350004）
