Re-Os AGES OF THE ZHONGJIA TIN POLYMETALLIC DEPOSIT,SOUTHWESTERN FUJIAN, AND THEIR GEOLOGICAL SIGNIFICANCE

The mineralization age of ore deposits is one of the important subjects in the study of the genesis of ore deposits and it has long been obtained by means of indirect methods.The Re-Os dating technique is an effective means for the direct accurate determination of the model ages of molybdenite and related mineralization.The alkali fusion combined with ICPMS was used in this study to determine the Re-Os ages of molybdenite in the Zhongjia tin poly metallic deposit.The results indicate that the model age of mineralization of the Zhongjiatin polymetallic deposit is 193-196 Ma,assigned to the early stage of the early Yanshanian period.The biotite granite related to mineralization was emplaced during the late Indosinian-early Yanshanian The transformation from the Tethys tectonic domain to the circum-Pacific tectonic domain in the continent of southeastern China began in the late Indosinian.The tin polymetallic mineralization resulted from the transformation of the two tectonic domains.The determination of the early Yanshanian mineralization provides direct chronological evidence for looking for new regional ore prospect areas.