Electrical resistivity structure of the Xiaojiang fault system (SW China) and its tectonic implications
Electrical resistivity structure of the Xiaojiang fault system (SW China) and its tectonic implications
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DOI：
10.1016/j.jseaes.2019.01.031
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Ilya Lozovsky
中科院分区：
文献类型：
--
作者：
Xin Li;Denghai Bai;Xiaobing Ma;Yun Chen;Ivan M. Varentsov;Guoqiang Xue;Shuai Xue;Ilya Lozovsky
It is widely accepted that large-scale strike-slip faults play an important role in.accommodating the India‐ Eurasia convergence, but the relationships between surface.displacements and deep deformation along the faults remain largely uncertain. To.address this issue, new magnetotelluric (MT) images were obtained along two profiles.across the Xiaojiang fault system (XJFS), one of the most tectonically active areas in.southwest China. Although different in details, these two profiles show similar overall.crustal resistivity structures. The upper crust is generally resistive but separated by.several narrow, subvertical conductors that broadly coincide with the surface traces of.the XJFS. These fault zone conductors (FZCs) are interpreted to represent fault.damage zones that formed by strike-slip faulting/shearing along the XJFS and filled.with deeply-sourced magmatic and/or metamorphic fluids. The lower crust is broadly.characterized by enhanced conductivity and likely associated with partial melting at.high temperatures. These observations are consistent with other geophysical.measurements in this area and in favor of the development of ductile flow along the.XJFS, although the pattern of flow is more complex than previously suggested. Based.on these observations, we propose that active deformation along the XJFS can be.better described, in the brittle upper crust, by strike-slip motion along the.fluid-weakened faults, and by shear-enhanced ductile flow in the partially molten.lower crust. These two mechanisms are not mutually exclusive but rather may be.complementary to each other.
