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Numerous late Mesozoic (Late Jurassic to Early Cretaceous) granitic plutons are present along the southern margin of the North China Craton (s-NCC), which belongs to the northernmost tectonic unit of the eastern Qinling orogenic belt. This tectonic unit records multiple tectonothermal and metallogenic events that occurred after continental collision of the North and South China Cratons in the late Early to Middle Triassic. This study reports the zircon U-Pb ages and the whole-rock and apatite geochemical compositions of the Taishanmiao granite, one of the largest late Mesozoic plutons in eastern Qinling. Three phases of this granite, emplaced between ∼125 and ∼113 Ma, are characterized by uniformly high SiO2 and K2O but low CaO, TFe2O3, and MgO contents and enriched Nd isotopic composition with initial ε Nd values of −13.5 to −12.7. Geochemical features reveal that these are A-type granites derived from partial melting mainly of ancient crust. Temperatures obtained from Ti-in-zircon thermometry and oxygen fugacity (f O2) data indicate that the magma(s) formed at high crystallization temperatures (∼800°–840°C) and f O2 levels (fayalite–magnetite–quartz [FMQ] buffer −1.5 to +1.5). Comparison with neighboring granites, such as the ∼150–130 Ma adakitic Heyu granite and the ∼115 Ma Donggou ore-bearing granite porphyry, implies that the Heyu granite formed from thickened crust and that the Donggou granite porphyry and Taishanmiao granite likely originated from a consistent magma system during the crustal thinning that occurred ∼125–113 Ma, except the porphyry rock was more evolved. This finding implies that their uniform magma chamber could provide sufficient metals and associated materials and even energy for the Donggou Mo deposit. [ABSTRACT FROM AUTHOR]

The Qinling orogenic belt in central China resulted fromthe final collision of theNorth China and South China blocks in the Triassic. Early Mesozoic granitoids are widespread in the Qinling orogen. Their genesis can provide key constraints on the tectonic evolution of this orogenic belt. The Late Triassic Baoji pluton, located in the North Qinling unit, consists of granodiorites, monzogranites, quartz monzodiorites, and K-feldspar granites. U-Pb zircon dating via the laser ablation ICP-MS technique yields ages of 217.4 ± 1.4, 212.3 ± 1.8, 212.6 ± 1.6, and 195.1 ± 2.0 Ma for granodiorites, monzogranites, quartz monzodiorites, and K-feldspar granites, respectively. The granitoids have high-K calc-alkaline, metaluminous to weakly peraluminous composition(s). Silica contents increase andMg, Fe, Ti, Ca, and P contents decrease from quartz monzodiorites through granodiorites to monzogranites and K-feldspar granites. Combining our findings with evidence from whole-rock Sr-Nd and zircon Hf isotopes, we suggest that the granodiorites formed by magma-mixing processes involving metasomatized lithospheric mantle and Mesoproterozoic crustal material. Themonzogranites record the contribution of an asthenospheric mantle source. The quartzmonzodiorites were derived fromametasomatized lithosphericmantle source. Partialmelting of crustal lithologies generated the K-feldspar granites. It is argued that the Baoji pluton formed in a late-collision setting. [ABSTRACT FROM AUTHOR]