Zircon U-Pb Ages and Geological Significance of Metamorphic Basic Intrusive Rocks in the Acite Area of East Kunlun

The Acite metamorphic basic intrusive rocks in Balong area, Dulan County, located in the eastern section of the central tectonic belt of East Kunlun, are intruded into the Mesoproterozoic Xiaomiao Formation and Paleozoic granitic gneiss. Field geology, petrology and geochemistry characteristics claim that these Acite metamorphic basic intrusive rocks belong to orthometamorphic rocks, and their protoliths are tholeiitic gabbro. The zircon LA-ICP-MS U-Pb geochronology analysis has been conducted for these intrusive rocks, the obtained zircon U-Pb ages vary from(240.8±2.8)Ma to (241.9±7.3)Ma, which belong to middle Triassic.The zircon morphology and geochemistry characteristic show that these zircons have same characteristics with magmatic zircon, representing the forming age of the Acite metamorphic basic intrusive rocks. The abundant captured zircons in these samples were recorded multiphase tectono-magmaticevents of East Kunlun in Precambrian period.