Effects of Mantle Flow on Generation and Distribution of Global Lithospheric Stress Field

Abstract

We apply the kinematic simulation modeling method to study the effects of mantle flow on the generation of global lithospheric stress field. The internal density anomalies and surface plates' movements both drive the mantle circulation. Mantle flow causes normal stress and tangential stresses at the bottom of the lithosphere, and then the sublithospheric stress field induces the lithospheric deformation as surface force and results in the stress field within the lithosphere. The simulation shows that the agreement between predictions and observations is good in most regions. Most of subduction zones and continental collisions, such as the circumpacific subduction zone and the collision zone between the India and Eurasia plate, are under compression. While ocean ridges, such as the east Pacific ridge, the Atlantic ridge and the east African rift valley, are under tension. And most of the hotspots preferentially occur in regions where calculated stress is tensile. The calculated directions of maximum principal horizontal compressive stresses are largely in accord with that of the observation except for some regions such as the NW-Pacific subduction zone and Qinghai-Tibet Plateau, in which the directions of the maximum principal horizontal compressive stress are different. It shows that the mantle flow plays an important role in causing or affecting the large-scale stress field within the lithosphere.