Constraints of the Age of Yingfeng Rock Mass on the Age of Wandonggou Group in Tanjianshan Area of the Northern Margin of Qaidam

Wandonggou Group is mainly composed of carbonate, schist and phyllite,preferable geologically for gold deposit prospecting. However, there has not been a unified understanding on the distribution law of the Wandonggou Group because of the uncertainty of its forming age and the difficulty in distinguishing it from Daken Daban Group, which results in slow proceeding in gold deposit prospecting in Tanjianshan area of the northern margin of Qaidam. This paper carried out zircon U-Pb chronology research on the age of the intruding Yingfeng rapakivi granite and obtained the weighted average age of (1 773.1±3.7) Ma.The intrusive contact of Yingfeng rapakivi granit with the direct surrounding rock, the formation age of Mesoproterozoic fossils from Wandonggou Group and the regional comparison with Daken Daban Group redefined segment B of Wandonggou Group, the direct surrounding rock of Yingfeng rapakivi granite, as Daken Daban Group. The optimized definition of Wandonggou Group provides a basis for the deployment of the gold deposit prospecting in the northern margin of Qaidam and the Tanjianshan Area.