TIMS U-Pb zircon ages of Fuyun post-orogenic linear granite plutons on the southern margin of Altay orogenic belt and their implications

A series of post-orogenic granite plutons occur on the southern margin of Altay orogenic belt.A gneis- sic deformed granitic pluton occurs in the Ertix faulted zone to the south of Fuyun,intruded by an underformed granitic pluton.The former pluton is dated by U-Pb TIMS method at 281±5 Ma and the latter at 275±2 Ma. These data indicate that shearing deformation still took place to some extent along Ertix zone during ca.280～ 275 Ma in the post-orogenic period.The deformation probably ended or became much weaker after 275±2 Ma.