Contrasting morphological trends of islands in Central Philippines: Speculation on their origin |
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| Authors: | Graciano P Yumul JR Carla B Dimalanta Rodolfo A Tamayo JR and Jenny Anne L Barretto |
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| Institution: | Rushurgent Working Group, National Institute of Geological Sciences, College of Science, University of the Philippines, Diliman, 1101, Quezon City The Philippines, (email:;),Ocean Research Institute, University of Tokyo, Tokyo, Japan,;UMR 6538 Domaines Océaniques, Universitéde Bretagne Occidentale, Brest, France |
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| Abstract: | Abstract The Palawan microcontinental block collided with the Philippine Mobile Belt in the Central Philippine region resulting in the counterclockwise rotation of Mindoro– Marinduque and clockwise rotation of Panay. The collision also brought about the clockwise rotation of north-east Negros, Cebu, north-west Masbate and Bohol (collectively called the Western Visayan block), resulting into their present-day northeast–southwest trend. This suggests a far more dramatic role of the collision than was previously recognized. Furthermore, the south-east Sulu Sea sub-basin is inferred to have also undergone collision-related clockwise rotation which can account for the observed east-west trending magnetic lineations in the basin. Aside from explaining the contrasting morphological trends of the different islands in Central Philippines, the rotation can also explain, albeit in a different way, how the belts of sedimentary basins, ophiolites and arcs in Panay and Negros can extend to Northern Luzon. Published paleomagnetic data suggest that the collision-related rotation commenced during the early to middle Miocene and had ceased by the late Miocene. |
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| Keywords: | collision indenter tectonics microcontinent ophiolites Philippines rotation |
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