Zircon U-Pb age and petrogenesis of ore-bearing granitoid for the Chigou Cu-Mo deposit from the Zhashan basin, Shaanxi Province
陕西柞山盆地池沟铜钼矿区含矿岩体的锆石U-Pb年龄和岩石成因

There have plenty of Cu-Mo deposits (occurrences) which are genetically associated with intermediate-acid granitoid stock from the Zhashan basin in the Qinling Orogenic Belt, recently huge copper orebody has been discovered in the Chigou Cu-Mo deposit region, but the timing and petrogenesis of ore-bearing granitoids were poorly constrained. In this contribution, ore-bearing granitoids for the Chigou Cu-Mo deposit were selected; geochemistry and LA-MC-ICPMS zircon U-Pb data for these rocks have been carried out. They are dominantly quartz diorite, diorite and porphyritic granite in petrology, and geochemically belong to high potassic calc-alkaline I-type granitoid, geochemical and Sr-Nd isotopic evidence demonstrate that these rocks originated from partial melting of upper mantle and lower crust. The weight average 206Pb/238U ages for these ore-bearing granitoids are ~145Ma. In combined with regional geological characteristics and relation between igneous rocks and mineralization, it is proposed that the Chigou ore-bearing igneous rocks were formed during the Late Jurassic-Early Cretaceous time, and it is indicated that there have regional Late Jurassic-Early Cretaceous granitoid and porphyry-skarn Cu-Mo ploymetallic deposits in the Zhashan basin, synchronously the formation of granitoid batholith or stock and the corresponding porphyry Mo-hydrothermal vein Zn-Pb-Ag deposits in South margin of North China Craton.