Abstract

• Win Gyi area is located in the south-eastern part of Wuntho Massif and characterized by the lithologic units of (i) plutonic rocks of Kanzachaung Batholith, (ii) volcanic rocks of Mawgyi Volcanics, and (iii) volcanoclastics and volcanic rocks of the Mawlin Formation. Gold mineralization in the study area is mainly confined to the andesitic unit of Mawgyi Volcanics and, hence, we study the petrography and geochemistry of Mawgyi Volcanics to determine petrogenesis and tectonic setting. Mawgyi Volcanics mainly consist of porphyritic andesite and basalts. A geochemical study indicates that the volcanic rocks possess of SiO2 (48.5- 57.9 %), Na2O (1.21-6.55%), K2O (0.13-0.5%), MgO (4.5-7.18%), Fe2O3 (9.27-11.2%), and TiO2 (0.741.08%), mostly show calc-alkaline characteristics. Chondrite-normalized REE patterns and primitive mantle-normalized spider diagram reveal that the volcanic rocks are derived from slab derived fluids, resulting from partial melting of the metasomatized mantle wedge. The volcanic rocks were formed by the subduction of the Neo-Tethyan oceanic lithosphere to the Eurasia plate during Cretaceous.