~(40)Ar-~(39)Ar DATING OF SERICITE IN THE SONGKAERSU CU-AU DEPOSIT OF EASTERN JUNGGAR,XINJIANG

The porphyry-type Songkaersu Cu-Au deposit occurred in Carboniferous continental volcanic belt of Karamaili and related to the continental volcanic-intrusive rocks.Mineralization mainly takes place in the contact zone of granite porphyry.In order to obtain the metallogenic time,the sericites separated from the phyllic zone of the altered granite porphyry was measure.The 40 Ar-39 Ar analysis of plateau age and isochron age yield(338.6±2.2)Ma and(341.5±3.9)Ma,respectively.The former represents the ore-forming age.It is suggested that the porphyrytype metallogenesis in the Songkaersu deposit took place in Early Carboniferous,which is consistent with the ages of the continental volcanic-intrusive rocks and the epithermal Au mineralization in the adjacent regions.It reveals that the Songkaersu porphyry Cu-Au deposit and the epithermal Au deposits were formed in the same magma-fluid mineralization system controlled by extrusionextension conversion period in post collision environment.