【摘要】 本文将横向黏度变化提高到3个量级,获得了地震波速度结构约束下的大横向黏度变化的地幔浅部的极型场和环型场对流图像.与小横向黏度变化下的结果相比,本文的结果具有显著的改善.对极型场对流图像,主要体现在本文结果能更清楚地解释太平洋板块、大洋洲和南美洲以及东太平洋洋中脊处的现今运动状态;对环型场对流图像,能更合理地解释北太平洋板块的右旋运动.本文计算的极型场、环型场对流速率以及揭示的某些区域如欧亚大陆和非洲大陆的运动状态与现今地表板块的运动速率以及欧亚板块和非洲板块的运动状态有明显差异,但相比小横向黏度变化下的结果,有助于更好地认识和理解现今地表板块运动的深部动力学过程.更多还原

【Abstract】 In the present paper,the poloidal and toroidal convection patterns at shallow depths of the mantle were obtained for the mantle convection model with large lateral variable viscosity (LVV)of 3 orders constrained by seismic wave velocity.Compared with the results of small LVV,the results in this paper were bettered remarkably.It mainly showed that we could interpret more reasonably the current motion states of the Pacific plate,the Oceania and the South America and at the ridge of the eastern Pacific Ocean from the poloidal convection patterns and the clockwise rotations of the northern Pacific plate from the toroidal convection patterns in this paper.The computed poloidal and toroidal convection rates and the motion states in some regions such as Euro-Asian and African continents revealed by convection patterns were different from the motion rates of current plates and the current motion states of Euro-Asian and African plates,but compared with the results of small LVV,it could be helpful to understand and recognize more reasonably the deep dynamic processes of current plate motions.更多还原