LA-ICP-MS zircon U-Pb age and geochemical characteristics of quartz diorite from the Haxiyatu iron-polymetallic ore district in Eastern Kunlun

Eastern Kunlun region is an important skarn-type iron-polymetallic metallogenic belt in Qinghai Province, and the Haxiyatu iron-polymetallic deposit is related to the intermediate intrusive body discovered in recent years in the area of Jinshuikou rock group. The iron, gold and zinc reserves of the deposit have reached a medium-size deposit. The mineralization has a close relationship with quartz diorite in northeast mining area, and the orebody occurs in the outer contact zone of quartz diorite. LA-ICP-MS isotope dating of zircons from the quartz diorite yielded an age of 246.8±1.8Ma (MSWD=0.074), suggesting that the quartz diorite was formed before Early Triassic and that there existed skarn mineralization in Eastern Kunlun area in Early Triassic. Geochemical studies indicate that quartz diorite is of high-K calc-alkaline series and has the attribute of Andean type epicontinental igneous tectonics. It is thus held that the quartz diorite was formed after the northward subduction of Animating ocean basin which caused the mixing, emplacement and crystallization differentiation of the crust mantle magma.