Abstract

• Tagu Taung area is situated about 59 km southeast of Myeik, Tanintharyi Region. In the study area, porphyritic granite intrudes the metasediments of the Carboniferous to Early Permian Mergui Group. Porphyritic granite is medium- to coarse-grained and characterized by the phenocrysts of feldspar. It is mainly composed of quartz, plagioclase, microcline, perthite, orthoclase, muscovite, biotite, chlorite and zircon. Geochemical data indicates that the granites from the study area have A/CNK ratio (1.2-1.4) is greater than 1.1 expressing peraluminous and S-type. When plotted in the (Y+Nb) / Rb discrimination diagram, Tagu Taung granites occupy syn-COLG (syncollisional granite) setting. Therefore, it can be said that these S-type granites are formed at syncollisional setting. The W-Sn mineralization is spatially and genetically associated with porphyritic granite. W-Sn ores are associated with sulfide bearing quartz veins that intrude the graywacke and granite. There are two stages of mineralization: namely greisen stage and vein stage. Molybdenite, chalcopyrite and sphalerite were deposited during the greisenization process (early stage). Successively, wolframite, cassiterite, arsenopyrite, pyrite, chalcopyrite, bismuth and sphalerite formed in the vein stage. The Sn-W mineralization is genetically related to the S-type granite emplacement that is resulted from the partial melting of the crust.