Whole rock geochemistry shows that the Pugo and Lepanto Metavolcanics exhibit transitional island arc tholeiite - mid- ocean ridge basalt characteristics while the Quaternary (?) andesite-dacite dikes intruded into the basement complex, silicic plutons and sedimentary cover display island-arc signatures. Fractional crystallization, magma mixing and to a certain extent, assimilation are involved in the generation and evolution of the Pugo and Lepanto Metavolcanics. Several pulses of magmatism are believed to be responsible for these rocks. Field, petrographic and whole rock geochemical data suggest that the Baguio Mining District is floored by a subduction-related marginal basin crust that served as platform to later-stage silicic intrusives.