西藏中冈底斯带措勤地区则弄群熔结凝灰岩锆石LA-ICP-MS U-Pb年龄

Zircon LA-ICP-MS U-Pb age of ignimbrite from Zenong Group in Coqen area of the central Gangdese belt, Tibet, China.

摘要: 对措勤地区则弄群熔结凝灰岩进行了LA-ICP-MS锆石U-Pb定年，所测的2件熔结凝灰岩样品的LA-ICP-MS锆石U-Pb年龄分别为112.7Ma±1.0Ma和108.6Ma±1.6Ma。根据已有的年代学数据、地球化学资料和最新的1∶25万区域地质调查成果，认为中冈底斯北部的则弄群火山岩很可能与班公湖-怒江特提斯洋向南的俯冲作用有关。

Abstract: To ascertain the genesis and regional correlation, the authors measured the LA-ICP-MS zircon U-Pb ages of ignimbrite from Zenong Group widely developed in the Coqen area. LA-ICP-MS zircon U-Pb ages of two ignimbrite samples are respectively 112.7±1.0Ma and 108.6±1.6Ma. According to the chronological data, geochemical data and latest 1∶250000 regional geological survey results obtained, the authors believed the Zenong Group volcanic rocks in the northern central Gangdese were most likely associated with southward subduction of Bangong Co-Nujiang Tethys oceanic crust.