Zircon U-Pb geochronology and Hf isotopic constraints on petrogenesis of Carnian Huanglonggou granodiorites in Wulonggou area of Eastern Kunlun Orogen,NW China

The Wulonggou area located in the Eastern Kunlun Orogen in NW China is characterized by exten-sive granitoid magmatism, ductile faulting and orogenic gold mineralization.The Huanglonggou granodiorite is cut by an orogenic gold-bearing fault.This study investigated the major and trace-element compositions, zircon U-Pb dates and zircon Hf isotopic compositions of the Huanglonggou granodiorite.One Huanglonggou granodior-ite sample yielded a weighted mean U-Pb zircon age of ～221 Ma ( Carnian) .The Carnian granodiorite is meta-luminous, with high alkalis contents of 6.37％-8.86％, high Al2 O3 contents of 15.41％-16.19％, high Sr contents of (426--475) ×10 -6 , relatively high Sr/Y ratios, high ( La/Yb) N values and low HREE, suggesting an adakite type high-SiO2 granite.The Huanglonggou granodiorite sample has zirconεHf ( t) values ranging from-4.4 to +1.1.These Hf isotopic data suggest that the Carnian granodiorite was likely derived from the partial melting of subducted Paleo-Tethys oceanic slab.It is suggested that the Late Triassic granodiorite was emplaced during the northward subduction of Paleo-Tethys oceanic slab.Orogenic gold mineralization in the Wulonggou area formed after the emplacement of the Late Triassic intrusive rocks.