笔者建立了基于地震层析成像的热地幔对流模型,并分别计算了有、无地袁板块运动约束下的中国大陆岩石圈底部的地幔对流速度场和水平剪切应力场.结果表明,欧亚板块运动速度对中国大陆地幔浅部的对流速度场影响较大,而对对流应力场的影响较小.在岩石圈底部(约100 km深度),对流速度方向差异基本上达到了50％,幅度差异达到了80％以上,而地幔对流应力场的差异在方向上基本上小于10％、幅度上基本上小于20％.因此,如果仅研究岩石圈底部地幔对流应力场,则可以采用无板块速度约束的热对流模型.但如果要研究地幔浅部的对流状态和格局,则需要考虑板块运动速度.%In this paper,seismic tomography-based thermal mantle convection models are presented and then used to predict the mantle convective velocity and mantle convection-induced horizontal shear stress (HSS) at the base of the lithosphere below Mainland China,with or without constraint of surface plate motions.Our results show that motions of the Eurasian plate have larger effects on the convective velocity than on HSS in the uppermost mantle beneath Mainland China.At the base of the lithosphere (at depth ～ 100 kin),the percent difference between the directions of convective velocities predicted by the two models above is almost above 50％,and that between the amplitudes is almost larger than 80％;whereas for HSS,the percent differences are almost smaller than 10％ and 20％ in direction and amplitude,respectively.Therefore we conclude that,if it were only to predict the basal HSS of the lithosphere due to mantle convection,the thermal mantle convection model without constraint of the Eurasian plate motions could be adopted;however,if the convective state and pattern in the uppermost mantle were to be investigated,it is necessary to consider surface plate motions.
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