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Emplacement Ages and Petrogenesis of the Molybdenum–bearing Granites in the Jinduicheng Area of East Qinling, China: Constraints from Zircon U–Pb Ages and Hf Isotopes
Author(s) -
Hongying LI,
Xiaoxia WANG,
Huishou YE,
Lei YANG
Publication year - 2012
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2012.00694.x
Subject(s) - zircon , geology , geochemistry , molybdenite , petrogenesis , crust , molybdenum , partial melting , geochronology , mantle (geology) , petrology , fluid inclusions , paleontology , quartz , materials science , metallurgy
Abstract: The Mesozoic porphyry assemblage in the Jinduicheng area is a special molybdenum area in China, the Mo deposits, including the Jinduicheng, Balipo, Shijiawan, Huanglongpu, are distributed. The emplacement age and geochemical features of the granites in the Jinduicheng area can provide essential information for the exploration and development of the porphyry molybdenum deposit. In this study, we report LA–ICP–MS zircon U–Pb age and zircon Hf isotopic compositions of granite porphyries from the Jinduicheng area, and provide insights on the petrogensis and source characteristics of the granites. The results show that the zircon U–Pb ages of the Jinduicheng granite porphyry (143±1 Ma) and the Balipo granite (154±1 Ma), agree well with the Re–Os ages of molybdenite in the Jinduicheng molybdenum polymetallic deposit (139±3 Ma) and the Balipo molybdenum polymetallic deposit (156±2 Ma), indicating that the emplacement of granite porphyries occurred between Late Jurassic and Early Cretaceous. Zircons granite from the Jinduicheng area give the ε Hf ( t ) values mainly ranging from –10 to –16, and –20 to –24, respectively, corresponding to two–stage model ages ( t DM2 : mainly focused on 1.86–2.0 Ga, and 2.2–2.6 Ga, respectively) of zircons of the granite from the Jinduicheng values. The ore–forming materials are mainly derived from crust, with minor mantle substances. Zircons of the granite from the Balipo area give ε Hf ( t ) values ranging from –18 to –20, –28 to –38, and –42 to –44, respectively, corresponding to two–stage model ages ( t DM2 : mainly focused on 1.88–3.0 Ga, and 3.2–3.90 Ga, respectively), the ε Hf ( t ) values of the Jinduicheng porphyry more than that of the Balipo porphyry, and two–stage model ages ( t DM2 ) less than that of the Balipo porphyry, shows that he source of the porphyries originated from ancient lower crustal materials in the Jinduicheng area, and mixed younger components, more younger components contributed for the source of the Jinduicheng porphyry.