A new interpretation of the metamorphic core in the Taiwan orogen: A regional-scale, left-lateral shear zone that accommodated highly oblique plate convergence in the Plio-Pleistocene
A new interpretation of the metamorphic core in the Taiwan orogen: A regional-scale, left-lateral shear zone that accommodated highly oblique plate convergence in the Plio-Pleistocene
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DOI：
10.1016/j.tecto.2022.229332
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发表时间：
2022-04-26
期刊：
影响因子：
2.9
通讯作者：
Chang, Chung-Pai
中科院分区：
文献类型：
--
作者：
Ho, Gong-Ruei;Byrne, Timothy B.;Chang, Chung-Pai
在过去的几十年里，台湾的弧-陆碰撞通常被解释为一个相对连续的过程，至少在过去的6年里，板块会聚矢量是不变的。5 Ma.俯冲大陆边缘和板块边界之间的这种稳定的会聚，包括速率和结晶度，表明了一种传播碰撞，其时空等价性沿着发展中的造山带。最近，详细的低温地质年代学和板块重建表明，在过去的2至1 Ma，板块会聚从高度倾斜变为几乎正交。这种早期阶段的斜向会聚，主要是由菲律宾海板块wrt欧亚板块向北运动，意味着一个重要的？？？化石？沿推测为北向的板块边界沿着的左旋走滑运动分量。本研究中汇编的现有数据的综合表明，在Tailuko带存在以前未表征的走滑变形带，在这里，我们记录：1）水平剪切的分布，2）变形的运动学，3）变形的年龄，和4）地质研究和板块重建之间的区域一致性。在台湾南部的浅层构造层次，也可能记录到水平剪切，这是由脆性断层和块体旋转造成的。这些新数据与先前发表的跨走向运动学数据的整合也表明，板块会聚与后楔中的走滑运动（即，Tailuko带）和prowedge中的缩短（即，（Slate Belt）
In the past decades, the arc-continent collision in Taiwan was commonly interpreted as a relatively continuous process with an invariant plate convergence vector for at least the last 6???5 Ma. This steady convergence, including the rate and the obliquity, between the subducting continental margin and the plate boundary suggest a propagating collision with a space-time equivalence along the developing orogen. More recently, detailed lowtemperature geochronologic and plate reconstructions suggest that the plate convergence changed from highly oblique to nearly orthogonal in the last 2 to 1 Ma. This early phase of oblique convergence, driven primarily by the northward motion of the Philippine Sea Plate wrt the Eurasian Plate, implies a significant ???fossil??? component of left-lateral, strike-slip motion along the presumably north-trending plate boundary. A synthesis of available data compiled in this study suggests that previously uncharacterized zones of strike-slip deformation exist in the Tailuko Belt, and here we document: 1) the distribution of horizontal shear, 2) the kinematics of deformation, 3) the age of deformation, and 4) regional consistency between geologic studies and plate reconstructions. Horizontal shear may also be recorded at shallow structural levels in southern Taiwan by brittle faults and block rotations. Integration of these new data with previously published kinematic data across strike also suggests plate convergence was partitioned with strike-slip motion in the retrowedge (i.e., the Tailuko Belt) and shortening in the prowedge (i.e., the Slate Belt).