LA-ICPMS zircon U-Pb age of the Yemaquan granodiorite in the Qimantag area, Qinghai Province and its geological implications

Qimantag area in the western part of the East Kunlun orogenic belt is a characteristic intrusive magmatic structural belt, and is also an important polymetallic metallogenic belt. The Yemaquan Fe-Cu polymetallic ore district is a typical contact metasomatism skarn deposit. In this study, the authors obtained the petrogenetic age of the granodiorite (226±2Ma) by using LA-ICP-MS zircon U-Pb dating. The result is in agreement with previous isochron age of 225.0±4.0Ma for skarn copper molybdenum polymetallic ore and 230.1±4.7Ma for skarn type molybdenum ore obtained by molybdenite Re-Os method. It is thus held that the petrogenetic and ore-forming epoch is Middle-Late Triassic.