Onland signatures of the Palawan microcontinental block and Philippine mobile belt collision and crustal growth process: A review

The collision of the Palawan microcontinental block with the Philippine mobile belt had significantly influenced the geological evolution of the Philippines. Multiple collisions involving several fragments, through space and time, resulted into the collage of terranes of varying origin exposed in this part of central Philippines. Cusping of the overriding plate, volcanic arc gap, ophiolite emplacement, incipient back-arc rifting, island rotation and tilting, raised coastal terraces, metamorphism, intrusion of igneous rocks and steepened subducted slab as seen in focal mechanism solutions are some of the manifestations of this collision. A late Early Miocene to early Middle Miocene age (20–16 Ma) is proposed for the major collision between the Palawan indenter and the Philippine mobile belt. The collision boundary is located from the northern part of Mindoro through the central mountain range swinging east of Sibuyan Island in the Romblon Island Group and finally threading along the Buruanga Peninsula and eastern side of the Antique Ophiolite Complex before exiting and connecting with the Negros Trench. The collision, through accretion and crustal thickening, has contributed to the crustal growth of the Philippine archipelago.