Tectonic evolution of Taiwan

Abstract

Geologically Taiwan sits squarely on the continental shelf of the East China Sea and is considered as a coastal range of the Asiatic continent with the Tertiary eugeosyncline and miogeosyncline as side-troughs of the central Cordillera. Structurally Taiwan is situated at the junction of the Ryukyu Arc and the Philippine Arc and must have been affected by the eastward pulsation of the plate tectonics during the Tertiary that produced the islandarc system in the Philippine Sea Basin. One glaucophane schist belt occurred in the eastern flank of the Central Mountain and may tentatively be considered as representing a subduction zone in Late Miocene time. A mechanism of collision of continent—ocean type is here proposed with development of a synthetic thrust belt in the East Coastal Range and antithetic thrust belt in the western part of the island. In Plio-Pleistocene time, the Benioff zone assumed a vertical position through rotation and Taiwan experienced a remarkable bending from a linear trend to a concave structure due to the shifting of the direction of the movement of the Philippine Sea Plate from westerly to northwesterly, and since then it has become a less active region of block tectonics. In the Ryukyu—Taiwan—Luzon system, a correlation of the tectonic belts can be effectively made. However, the study of the tectonic history of Taiwan indicates that it had close relation with the Ryukyu-Arc during Miocene time, but is more closely affiliated with Luzon Island of the Philippines since Pliocene time.