GEOCHEMISTRY AND GEOCHRONOLOGY OF GRANODIORITES IN QUPANGLANGXIE AREA, NORTHERN BAYANKALA TERRANE

Through the study on the petrography, lithogeochemistry and geochronology of granodiorites in Qupanglangxie area, the paper discusses the genesis and tectonic environment of the intrusive rocks. The SHRIMP zircon U-Pb dating yields a weighted mean age of 213.8±2.0 Ma, indicating that the emplacement occurred in Mesozoic Late Triassic. The granodiorites are characterized by high Si, Al₂O₃ and Na, low K, poor in Ca, Mg and Fe, belonging to SiO₂ supersaturated and aluminum supersaturated I-type granite, with obvious enrichment of K, Rb and Th, deficiency of Sm, Hf, Zr, Y and Yb, and negative Eu anomaly. The granodiorites in the area were formed by the partial melting of crust caused by deep detachment structure in the stage of intracontinental collision orogeny.