Origin and Tectonic Evolution of TaipeiBasin
Chih-Yo Chien
Abstract
Taipei basin is located in the northern Taiwan mountain belt. Now the active collision zone is progressive to the south-central Taiwan, and the northern Taiwan is undergoing crustal extension. But the origin of Taipei basin has two different ideas. The one is extension collapse, and the other one is evolution of fault wedge basin. The tectonic evolutions separately are as follows.
Engineered by the northwest movement of the Philippine Sea plate, the collision orogen progressively enlarged and migrated from northeast to southwest. Following the southwest propagating collision, the north-dipping Philippine Sea plate extended westward and caused flipping of subduction in the northern part of the collision orogen. In consequence, the orogen lost the compressive support by the colliding plates and became subjected to lithospheric stretching induced by the trench suction. The Hsinchuang Thrust Fault on front of the mountain range was reactivated as the Shanjiao Normal Fault. The mountain located on the hanging wall collapsed and slid down to become a depression. At 400Ka, the depression slid down to near the sea level and began to pond fluvial sediments, with continued subsidence and deposition, the depression enlarged and eventually evolved to the present TaipeiBasin.
Due to the oblique collision of the Philippine Sea plate, the northeast-southwest strike thrust faults almost have left slip component. TaipeiBasin was formed by the divergent fault wedge basin on the horse tail branching fault system, composed of Hsinchuang fault, Kanchiao fault, and Taipei fault.
Reference
Teng, L. S., C. T. Lee, C. H. Peng, W. F. Chen, and C. J. Chu, 2001,Origin and geological evolution of the Taipei basin, northern Taiwan. W. Pac. Earth Sci., 1, 115-142
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