Exhumation History of Mindoro Orogenic Belt, South of Luzon (Philippines) and its Implication to Plate Motion of the Philippine Sea Plate

Mindoro orogenic belt, south of Luzon (Philippines) locates on southernmost of the Manila trench that result from collision between North Palawan block and the western Philippines Mobile belt. This collision process exposed the Mesozoic metamorphic basement along the strike of orogenic belt. Previous studies suggest two different models for the timing of collision, early Miocene or late Miocene. In this study we conduct the zircon fission track dating(ZFT) to reveal the timing of collision. We collected samples from bed rock and river sands along the strike of the orogenic belt and the samples locations also across the partial to total reset zone. The oldest reset ZFT ages for bed rocks range from 4-6 Ma and the river sand samples also shows the reset age group from 4-7Ma. The reset ZFT ages indicate the timing of mountain building started from late Miocene that is consistent with initial exhumation timing of Taiwan orogenic belt. Considering both orogenic belts show similar timing of mountain building we suggest that while Philippine sea plate changes the motion to NW trending in late Miocene that result in the Luzon arc/Philippine Mobile belt collides with Eurasia continental margin resulting in mountain building of Taiwan and Mindoro orogenic belts.