Acta Petrologica et Mineralogica

The North China Craton (NCC) has undergone a long and complicated geological process. During the Mesozoic, a series of intermediate-acid granitoids were formed in the Taihang Mountains. Mapeng granitic pluton is located in the northern part of Taihang Mountains, emplaced in Fuping complex, with porphyritic monzonitic granite, granodiorite and quartz diorite exposed from the center to the edge. The petrology, petrochemistry, genetic type of Mapeng granitic pluton have been studied by predecessors, but the type and source of granitic pluton are still controversial. In this paper, the petrochemistry, zircon SHRIMP U-Pb isotopic chronology and Lu-Hf isotopic composition of porphyritic monzonitic granite, granodiorite and quartz diorite in Mapeng pluton are systematically studied, and the geochemical type, formation age and magma source nature of Mapeng granite are further discussed. Geochemical magmas show that the Mapeng granite has high SiO₂、Na₂O+K₂O、Ba、Sr、LREE and the ratio of K₂O/Na₂O, lower Al₂O₃、MgO、Rb、Nb、Ta、Th、U、Y、HREE and Mg^#value, no obvious Eu anomaly and obvious depletion of high field strength elements such as Nb, Ta, P and Ti. The SHRIMP U-Pb isotopic ages of the three newly obtained granites with different facies belts are 129.4±1.4 Ma, 131.2±2.2 Ma, 129.5±1.3 Ma, and they have similar major element compositions and REE and trace element distribution patterns. It also reflects that the Mapeng pluton is a magmatic activity of the same period, and has undergone rapid emplacement and cooling crystallization. Lu-Hf isotopic analysis shows that the εHf(t) value of magmatic zircon from the Mapeng granite is -27.00~-15.44, and the two-stage model age t_DM2 is 2 358~1 765 Ma. The magma source of the Mapeng granite is the result of mixing of mantle magma and magma formed by partial melting of Precambrian metamorphic basement.

Mapeng pluton; zircon SHRIMP U-Pb age; Lu-Hf isotope; high Ba-Sr granite