Sandbox Models of Wulipai graben and Penghu basin of Taiwan and deformation front of Columbia orogenic belt

• Main Authors: Shih-ChoHuang, 黃士倬
• Other Authors: Ching-Weei Lin
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/08119991624657259096

碩士 === 國立成功大學 === 地球科學系碩博士班 === 101 === Understanding foothills and foreland basin evolution of the structure and the related mode, that can provide the necessary of domestic and international oil exploration and evolution of the infrastructure mode. In this study, sandbox model are used to better understand the structural style of Wulipai graben and Penghu basin where located offshore of Taiwan and deformation front of Columbia orogenic belt. The Wulipai graben which located at offshore of Miaoli, is mainly bounded by east - west trending normal fault, but the dominant faults turn into northeast - southwest trending in western part. Therefore, the sandbox model focused on the occurrences of two different trending fault and its related geological structures. Penghu basin which located in southwestern offshore of Taiwan, is a typical half - graben basins. The main boundary fault is northeast – southwest trending, and the entire basin was separated by east - west trending faults. Therefore, the sandbox experiment also focused on the occurrences of two different trending fault and its related geological structures. For the deformation front of Columbia orogenic belt, sandbox model focused on the development of structural style of multiple vergence, and ramp - flat geometry of thrust system. Based on normal fault experiments, the study results show that the dip and geometry of fault is highly affected by throw of fault. When the ratio of thickness of sand and throw of fault is 1.82 - 3.33, the structure morphology of what are convex upward normal faults; When the ratio of sand thickness and fault throw is 4.18 - 8.50, the structure morphology of what are listric normal faults or both convex upward normal faults and convex upward reverse faults. For thrust experiments, ramp spacing controls the location and spacing of thrust faults in sand layers. In the model without external compression stress, thrusts in sand layer are parallel to the strike of the backstop. When there is an intersection between compression direction and strike of ramp, the morphology of fault is divergent.