The Baguio Mining District consists of Late Cretaceous ophiolite basement rocks. These are overlain by Eocene back arc tholeiitic Pugo Metavolcanics. These grade into the Dalupirip Schist, which is separated from the Early Oligocene-Early Miocene sedimentary Zigzag Formation by an unconformity. The Zigzag is composed of deep depositional environment interbedded green sandstones, red siltstones, oligomicitc conglomerates, and minor limestone units. The late Early Miocene-early Middle Miocene reefal Kennon Limestone overlays the Zigzag. The Late Oligocene-Early Miocene Agno Batholith intrudes the Pugo and Zigzag. The Middle-Late Miocene Klondyke Formation was deposited during Central Cordillera geologic uplift, consisting of coarse clastics, polymictic conglomerates, sandstones, and vitric (glassy) tuffs, with minor shales and siltstones. Gold mineralization occurred with dioritic and gabbroic intrusions, and basaltic to andesitic lavas, including the Monglo adakite. The Pliocene Baguio Formation consists of conglomerates interbedded with lava flows and pyroclastics. Pleistocene gold-copper mineralization occurred with calc-alkaline and dioritic and dacitic adakitic intrusions. This mineralization characterizes the Philex Mine.