Triassic convergence and tectonic evolution of the West Qinling orogen: Constraints from reflection-seismology imaging

作者：Li, Huilin; Gao, Rui; Huang, Xingfu^*; Wang, Haiyan; Guo, Xiaoyu; Liang, Hongda; Tan, Xiaomiao; Liu, Xiaohui; Yang, Zhen

来源：Gondwana Research, 2023, 122: 1-10.

DOI：10.1016/j.gr.2023.05.020

• West Qinling orogen
• Seismic reflection profile
• Tectonic evolution
• Mianlue Ocean
• Lithospheric structure

Although it is well known that the West Qinling orogen was created by the convergence and collision be-tween the North China block (NCB) and the South China block (SCB), the process of the microplate con-vergence in the West Qinling orogen and its adjacent blocks remains poorly understood. Here we address this question by analyzing ti 400 km seismic-reflection-profile data to constrain the subsurface structure of the orogenic system. Our data reveal two north-dipping reflection sets sandwiched between a sub-horizontal Moho (16 s to 18 s, t.w.t.) and a decollement zone (-6 s, t.w.t.) that separates the upper and mid-lower crusts. In detail, two sets of north-dipping reflectors occur beneath the Zoige basin (CDP 3000-4500, NR-1) and the southern West Qinling orogen (CDP 7000-10500, NR-2), which correlate to south-directed thrusts and are best interpreted as the result of the closure of the Paleo-Tethys Mianlue ocean in the early Triassic. This interpretation is consistent with the presence of an ocean separating the southern West Qinling orogen (S-WQO) from the northern West Qinling orogen (N-WQO). The origin of the required ocean is likely to be a branch of the Paleo-Tethys Mianlue ocean. & COPY; 2023 International Association for Gondwana Research. Published by Elsevier B.V.

• 单位
  中山大学; 桂林理工大学; 中国科学院