The Baguio Mining District is underlain by a marginal basin crust, the Pugo Metavolcanics,
that was later intruded by island arc magmas. The available geological information does not support the presence of a complete exposed ophiolite suite, a crust-mantle sequence, in the area. The Baguio Mining District and the Mankayan Mining District are floored by a common volcanic basement, with the Pugo Metavolcanics considered as equivalent to the Lepanto Metavolcanics, suggesting that these two districts and the area in between may actually be one single terrane.