Cleavage fronts and fans as reflections of orogen stress and kinematics in Taiwan

作     者：Fisher, Donald M. Willett, Sean En-Chao, Yeh Clark, M. Brooks 

作者机构：Penn State Univ Dept Geosci University Pk PA 16802 USA Univ Washington Dept Earth & Space Sci Seattle WA 98195 USA Natl Taiwan Univ Dept Geosci Taipei 10617 Taiwan ExxonMobil Explorat Co Houston TX 77210 USA 

出 版 物：《GEOLOGY》 (地质学)

年 卷 期：2007年第35卷第1期

页      面：65-68页

核心收录：

学科分类：0709[理学-地质学] 081803[工学-地质工程] 07[理学] 08[工学] 0818[工学-地质资源与地质工程] 

主　　题：cleavage fan cleavage front Taiwan slaty cleavage incremental strain 

摘      要：Recent observations of cleavage patterns, strain histories, and kinematics across the Taiwan mountain belt depict systematic orogen-scale variations with respect to the synorogenic divide and suggest that the pattern of cleavage development is a predictable consequence of orogen stresses and kinematics. In Taiwan, continental crust within the collision is accreted in the prowedge facing Asia, but is advected eastward into the east-verging retrowedge, where the most deeply exhumed rocks are exposed. Wedge mechanics predict a reversal in the direction of plunge of the principal compressive stress at the topographic divide between the opposing wedges. The observation of a single cleavage in western Taiwan suggests that the cleavage in the prowedge remains stable with respect to the stress orientation. In contrast, the existence of a second crenulation cleavage in the retrowedge is evidence for an abrupt change in stress orientation and unstable buckling of preexisting prowedge fabrics. Advection of a fabric across a topographic divide in a doubly vergent wedge provides an explanation for the occurrence of cleavage fronts and fans in natural systems such as Taiwan.