Deformation front development and strike variation at the east margin of Taiwan thrust belt

Chuang, Chieh-wei

Abstract

A model of imbricate thrust wedges based on the conceptual model of the critically tapering wedge is discussed and applied to the case of the Taiwan thrust belt. This model takes into account (1) the occurrence of compressional features located far from the foreland of the orogen and (2) the occurrence of deep-crustal decoupling that allows both the regional stress field to be transmitted in the foreland and the basement to be involved in the orogenic wedge. The along-strike structural changes are usually accompanied by changes in tectonic regimes due to local effects such as frontal contraction and lateral movement in response to indentation by the basement highs. This suggests that single-minded models based solely on the principles of either thin-skinned or thick-skinned tectonics may be unrealistic in the case of the Taiwan thrust belt. In addition, based on surface geology and subsurface well and geophysical data , The geological setting south of the Tsengwen River and the Tsochen Fault is the transitional zone between the Tainan foreland basin and Manila accretionary wedge in Southwestern Taiwan. This transitional zone is characterized by the triangle zone geological model associated with back thrusts that is quite unique compared to the other parts of the Western foreland that are dominated by thrust imbrications. Structures in the the Tainan and Kaohsiung areas provide important features of the initial mountain building stage in Western Taiwan. The Hsinhua structure, the Tainan anticline, and the H2 anticline formed a western most deformation front aligned above the leading detachment during the Penglay Orogeny in Southwestern Taiwan.

 

Reference

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