Scholarlink

<p>The Sichuan-Yunnan region (SYR) in the eastern and southeastern margins of the Tibetan Plateau covers the central and southern parts of the North-South Seismic Zone in China. As a key frontier tectonic zone of the India–Eurasia collision, its lithospheric deformation mechanisms are crucial for understanding plateau material extrusion and intracontinental tectonic evolution. In this study, we present a lithospheric azimuthal anisotropic model as a part of the seismic body-wave sphere-layered anisotropic model for the SYR. The lithospheric anisotropy parameters are derived from teleseismic XKS (including SKS, PKS, and SKKS phases) splitting. The model reveals a pronounced north-south contrast in lithospheric anisotropy across the SYR. In the north, anisotropy is oriented predominantly NW–SE, whereas in the south, it rotates to an approximately E–W orientation, with a sudden change near 26.5°N. This boundary reflects differences in upper mantle dynamic processes. In the north, the model supports the crust-mantle coupling, reflecting likely coherent eastward extrusion of Tibetan Plateau crust and mantle material under the ongoing northward subduction of the Indian plate. In the south, the model supports the crust-mantle decoupling, associated with likely slab rollback-induced mantle flow. The spatial distribution shows clear zonation in deep deformation patterns, closely related to tectonic blocks. In addition, in several small local zones, the inconsistencies among XKS results from different studies indicate the presence of complex deep structures, which require further constraints with better measurement data.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Body-wave anisotropic model AniCD-L: Illuminating the zonation of lithospheric azimuthal anisotropy by XKS splitting in the Sichuan-Yunnan region of SW China

  • 期刊论文

  • 发表日期：

    2026年4月22日

查看全文
  • Xinyi Li,
  • Yuan Gao,
  • Yutao Shi,
  • Yiwen Yang

摘要

The Sichuan-Yunnan region (SYR) in the eastern and southeastern margins of the Tibetan Plateau covers the central and southern parts of the North-South Seismic Zone in China. As a key frontier tectonic zone of the India–Eurasia collision, its lithospheric deformation mechanisms are crucial for understanding plateau material extrusion and intracontinental tectonic evolution. In this study, we present a lithospheric azimuthal anisotropic model as a part of the seismic body-wave sphere-layered anisotropic model for the SYR. The lithospheric anisotropy parameters are derived from teleseismic XKS (including SKS, PKS, and SKKS phases) splitting. The model reveals a pronounced north-south contrast in lithospheric anisotropy across the SYR. In the north, anisotropy is oriented predominantly NW–SE, whereas in the south, it rotates to an approximately E–W orientation, with a sudden change near 26.5°N. This boundary reflects differences in upper mantle dynamic processes. In the north, the model supports the crust-mantle coupling, reflecting likely coherent eastward extrusion of Tibetan Plateau crust and mantle material under the ongoing northward subduction of the Indian plate. In the south, the model supports the crust-mantle decoupling, associated with likely slab rollback-induced mantle flow. The spatial distribution shows clear zonation in deep deformation patterns, closely related to tectonic blocks. In addition, in several small local zones, the inconsistencies among XKS results from different studies indicate the presence of complex deep structures, which require further constraints with better measurement data.