ON SPHERICAL MANTLE MIXTURE DRIVEN BY MODERN PLATE TECTONIC MOTION
Shan Bin 1,2) ;Fu Rongshan 3) ; and Zheng Yong 4)
1) Institute of Geodesy and Geophysics, CAS, Wuhan 4300772) Graduate School of Chinese Academy of Science, Beijing 1000493) School of Earth and Space Science, University of Science and Technology of China, Hefei 2300264) Institute of Geophysics, CEA, Beijing 100081
Abstract This paper simulated the pattern of mantle convection and its evolution process under the driven force from modern plate tectonic motion based on a 3D mantle convection model and then analyzed the mantle mixture effect further.The results show four main characteritics of mantle mixture: 1) Degree of mantle mixture is mainly controlled by tectonic driven forces. 2) The degree of material mixture in the upper mantle is higher than that in the lower mantle. About 80% elements in the upper mantle and 60% in the lower mantle have been past through by at least two curves. 3) The degree of mantle mixture also depends on the convection time. The longer the time, the higher the degree of mixture, but the trend of mixture increase is getting downward, that makes the existence of mantle heterogeneities under the full mantle convection environment possible. 4) Mantle convection type can affect the mantle mixture in quite a deal. The existence of toroidal convections can make the material travel much longer distance than spheroidal convections, thus increase the mixture effect efficaciously.
