U-Pb dating of Zicon from the Gaojian Group tuff in central Hunan Province and its geological implication

The Gaojian Group stata of Central Hunan regions are mainly distributed in the south of Congjiang-Hongjiang-Xupu-Lianyuan-Shuangfeng region, the outcropped completed geological section occur in Shuangfeng Gaojian, Shiqiaopu of Longhui and Chengbujiang. 30 zirconite grains were collected from tuff in the top of Zhuanqiangwan formation and the U-Pb age was dated by LA-ICP-MS, and the weighted average age of zirconite 206Pb/238U is (774.9±2.6)Ma, which provides new chronological evidence to classify and compare strata in the continental margin rift basin of post-Wuling Period in southeast edge of Yangtze platform. The dated age is obviously yonger than the age of related strata in northwestern Hunan, but close to the age of related strata in Xiajiang Group of eastern Guizhou. This finding is helpful for re-building the basin evolution, strata comparison and mineralization effect in the southeastern edge of Yangtze plateform of Neoproterozoic age. It can also be regarded as of strata significance in studying sedimental relationship and mineralization effect of basin-fill sequence.