LA-ICP-MS zircon U-Pb dating of syenite from Yushigou in Northern Qilian Mountain

The Yushigou ophiolite in Northern Qilian Mountain, which has developed relatively complete and typical ophiolite rock association, has received widespread attention. The authors conducted the chronological study of zircons from the syenite by means of LA-ICP-MS U-Pb. The weighted mean age of the zircons is 522.7±5.3Ma, which belongs to the Early Cambrian and confirms the earliest record of alkaline intrusive magmatic activity in Northern Qilian Mountain. At the same time, this age gives a constraint that the upper limit of the age of Yushigou ophiolite should be no later than 522.7Ma.