Petrogenesis and tectonics of the Naruo Porphyry Cu(Au) deposit related intrusion in the Duolong Area, Central Tibet

摘要: The Duolong area is the most important part of Western Bangong-Nujiang Suture Zone porphyry Cu(Au) metallogenic belt, in Tibet, China. Here new detailed data are presented from LA-ICP-MS zircon U-Pb, whole-rock geochemical, and in-situ Hf isotope analyses for igneous rocks large Naruo deposit (2.51 Mt Cu 82 t Au) which located ∼2 km NE (Duobuza Bolong) super-large gold-rich copper deposit. We integrated our results with previous research other deposits have identified timing, geodynamic setting, petrogenesis mineralization-associated magmatic events. Based on measurements, formations associated Early Cretaceous intermediate-felsic magmatism, consistent U-Pb ages 120 Ma. All main intrusive ore-concentrated similar lithogeochemical characteristics; they show a relative enrichment both light rare earth elements (LREEs) large-ion lithophile (LILEs: Rb, Ba, K, etc.) depletion heavy (HREEs) high field strength (HFSEs: Nb, Ta, Zr, Hf, etc.). Moreover, granite shows positive eHf(t) values between 1.38–7.37 suggesting that magmas were potentially derived partial melting depleted mantle wedge had been metasomatized by subducted slab-derived fluids or melts. This paper points out formation porphyry-epithermal was dominated northward subduction Bangongco Tethys Plate beneath Qiangtang block (124–114 Ma), when oceanic crust reached 50–70 km underground generated different degrees phase transformation, lead to melt produced dehydration amphibole minerals, wedge, induced magma. Those occurred continental arc tectonic margin environment ocean-continent setting Andes belt South America.