Petrogenesis of the Late Jurassic Granodiorite and Its Implications for Tectonomagmatic Evolution in the Nuocang District, Western Gangdeses

The Gangdese magmatic rocks of the southern Lhasa terrane, are generally thought to be an important window witness formation and evolution Neo-Tethys oceanic opening, subduction, closure, India-Eurasian continental collision. We investigated a new occurrence granodiorite in Nuocang district western Gangdese, conducted series analyses on their petrology, chronology, geochemistry. granodiorites have zircon U-Pb ages 151–154 Ma, which suggest that Late Jurassic granitoids present terrane. They relatively high SiO2, Al2O3, low K2O, Na2O, Sr/Y ratios, enrichments LILE LREE, depletion HFSE, with positive correlation between Rb Th, negative correlations SiO2 P2O5, Rb, Y, showing features I-type granites. (87Sr/86Sr)i values from 0.712231 0.712619, εNd(t) −9.56 −8.99, together εHf(t) −10.8 −5.0 (mean value −8.9) suggested probably sourced partial melting ancient parts mantle materials involving in. Combined previous geochronology geochemical data Mesozoic magmas belt, as well granodiorite, this paper, we propose formed margin arc environment triggered by northward subduction Neo−Tethys crust.