Re-Os isotope dating of the Da'ao tungsten-tin deposit in the Jiuyi Mountains,southern Hunan Province

The Da'ao tungsten-tin deposit in the Jiuyi Mountains,southern Hunan,is closely related to the Jinjiling composite granite which has the characteristics of aluminous A-type granite. The deposit types include the greisen type,altered granite type,fractured zone alteration type and greisen-quartz vein type. Based on the precise Re-Os dating of molybdenite from the ore-bearing greisen-quartz vein,a mineralization age of 151.3±2.4 Ma was obtained,which is consistent with the formation age (151-156 Ma) of granite,suggesting that the mineralization occurred simultaneously with the rock formation. An integrated analysis and comparison of highly precise mineralization ages obtained on a regional scale shows that the period of 150-160 Ma was the peak stage of Mesozoic large-scale mineralization in the Nanling region and that the Da'ao tungsten-tin deposit in the Jiuyi Mountains is just the product of this peak stage. The new data provide important isotope chronological evidence for the further study of the regional metallogenic characteristics and guidance of regional mineral prospecting.