基于岩石圈厚度和地幔横向黏度变化的地幔对流模型重估云南地区剪切波各向异性源的深度

在已有模型的基础上,考虑岩石圈厚度和软流层横向黏度的变化,本文建立了更接近地球实际情形的地幔对流模型,然后重新推测了导致云南地区剪切波各向异性的软流层源的深度.结果 表明:岩石圈厚度和软流层横向黏度变化对云南地区的软流层各向异性源的深度及软流层的变形程度和机制具有重要影响;软流层各向异性对云南西南部区域、东部区域北纬2...

Re-estimating the depth of shear wave splitting anisotropy in the Yunnan region by using a mantle convection model based on lithospheric thickness and lateral mantle viscosity variations

In the present paper, we propose a more realistic mantle convection model by introducing the lithospheric thickness and lateral asthenospheric viscosity variations into a previous model and re-estimate the depth of shear wave splitting (SWS) anisotropy. Our results indicate that the variations greatly affected the depth of asthenospheric source responsible for SWS anisotropy and the intensity and mechanism of asthenospheric deformation in the Yunnan region. Asthenospheric anisotropy obviously contributed to a SWS residing at 90-180, 170-330, and 200-320 km depths in southwestern Yunnan, eastern Yunnan south of 26°N, and the Sichuan Basin and its western margin, respectively. Asthenosphere responsible for a SWS in southwestern Yunnan and eastern Yunnan south of 26°N likely experienced large shear deformation and was primarily controlled by mantle flow-direction/flow-plane mode; whereas asthenosphere resposible for a SWS in the Sichuan Basin and its western margin likely experienced small shear deformation and was mainly controlled by strain mode.