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The Qinling Orogen in central China preserves the records of a complex geological and tectonic history, and also carries abundant mineral resources. Previous investigations on the Qinling Orogen have identified that the final transition from the Palaeo-Tethys Ocean to a continental orogen occurred in the Triassic, although the timing of the oceanic closure and the tectonic affinity of the Triassic Qinling belt have been poorly constrained. In this contribution, we compile the palaeomagnetic data and geological evidence related to sedimentation, magmatism and mineral systems. The palaeomagnetic data show that the Palaeo-Tethys Ocean in the Qinling Orogen gradually closed westward during the Triassic, terminating in the beginning of the Jurassic. Triassic strata are widely developed in the Qinling Orogen and conformably overlie the Permian strata. They are composed of carbonates and siliciclastic rocks that were strongly deformed and weakly metamorphosed during the Late Triassic to Late Jurassic. The Triassic magmatic rocks are dominated by I-type granitoids, with subordinate S-type and alkaline granites and minor carbonatite dykes, with a clear northward transition in lithology and geochemical features from the Mian-Lue Suture. Different types of Triassic mineral systems have been reported from this region, including sedimentary-hosted epizonogenic hydrothermal Hg-Sb, Pb-Zn ± Ag, Au deposits, metamorphic hydrothermal lodes of Au, Ag-Pb-Zn, Mo-Au and Mo, magmatic hydrothermal systems including porphyry Mo, breccia pipe Au, and carbonatite-hosted Mo deposits. We infer that the Triassic Qinling Orogen witnessed synchronous oceanic plate subduction in the west and continental linkage in the east, with a transition from oceanic basin to continental orogen through gradual subduction-related consumption of the oceanic plate. The Palaeo-Tethys Ocean closed in a westward scissor-like fashion in the Triassic and continental collision and extensive crustal shortening in the Jurassic, following which post-collisional extension occurred in the Early Cretaceous. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Dashui porphyry granitoids in the western Qinling Orogen are spatially associated with the Dashui gold deposit, but their ages and tectonic setting have not been well defined yet in previous studies. This paper reports the results and understandings obtained from our original study in geochronology and isotope and element geochemistry. SHRIMP zircon U-Pb dating yielded ages of 213.7 ± 2.7 Ma for granitic stock and 215.1 ± 2.5 and 210.2 ± 1.6 Ma for granitic dikes. The granitoids are characterized by high LREE but low HREE and HFSE. They have (87Sr/86Sr) i ratios of 0.706 to 0.709 and εNd(t) values of −5.3 to −7.6. The majority of zircons in the Dashui granitoids have εHf(t) values ranging from −6.2 to 6.7 and TDM2(Hf) ages from 743 to 1464 Ma. The isotope signatures, together with La/Y and Mg# values, show that the magmas are mainly sourced from partial melting of a subducted slab, and possibly assimilated immature sediments during upward migration. Thus, the Dashui granitoids most likely formed in a volcanic arc where supra-subduction zone melts assimilated lower crustal material no later than 215 Ma. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]