Zircon U-Pb Ages and Its Geological Significance of the MonzoniticGranite in the Aikengdelesite, Eastern Kunlun

Aikengdelesite is the first found porphyry molybdenum (copper) deposit in EasternKunlun for the past years and the degree of geological work and research for the deposit is quite low.The deposit lies to the Eastern Kunlun southern composite accretion belt. The hosted rocks are diorite, monzonitic granite, granite porphyry, medium-fine grain granite and volcanic rocks and sedimentary rocks of Hongshuichuan Group.In this paper,we present zircon U-Pb age data of monzonitic granite using laser ablation ICP-MS technique. The zircons of granite are mainly euhedral and hypidiomorphic texture, have clear ring and high Th/U ratio (0.83～1.47, average 1.15) which belong to the typical magmatic zircons. The results show that the intrusion mainly comes from late Hercynian but not late Indosinian period with the206Pb/238U average weighted age of (268.7±1.6) Ma (MSWD=0.24) and concordant age of (268.5±0.83)Ma (MSWD=0.051). Comprehensive analysis reveals that the research area has entered into oceanic crust subduction stage in 268Ma±.