Porphyry-type Cu (Mo, Zn) deposits have been discovered along the late Paleozoic Kokirqin arc in the western Tianshan Mountains of China, part of the Central Asian Orogenic Belt. The deposits include the Lailisigao’er Mo-Cu deposit, the 3571 Cu deposit, and the Lamasu Cu-Zn deposit. The ore-forming porphyries from these three deposits are predominantly intermediate-felsic and belong to calc-alkaline and transitional series. Laser ablation–ICPMS zircon U-Pb dating on ore-forming porphyries from the Lailisigao’er and 3571 deposits yields ages of 346.1±1.2 Ma and 354.0±0.68 Ma, respectively. The trace element compositions of these porphyries from these three deposits are similar to those formed in a continental arc setting and are characterized by enrichment of large ion lithophile elements and depletion of high field strength elements and heavy rare earth elements ) coupled with slightly negative Eu anomalies. These rocks also show high (87Sr/86Sr)t (0.70722–0.71028) and low ɛNd(t) values (−3.71 to +0.17), coupled with depletion of Ba relative to Th and elevated Th/Ce, Nb/Y, and Th/Yb ratios, suggesting that the porphyry magma originated from a partial melting of subducted sediments, mixed with minor melts produced by partial melting of mantle wedge components and involvement also of lower continental crust during emplacement. These three deposits belong to the first metallogenic group in the Chinese Tianshan, which formed from the Middle Devonian to the early Carboniferous in a continental arc environment related to a subducted oceanic slab; this group is distinguishable from a second group that formed in the Permian during a late collisional stage, in which regional collisional compression changed to extension.

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