地幔对流诱发的莫霍面起伏与下地壳塑性流动

摘要

本文用定量模型研究了在地幔对流作用下下地壳物质流动过程和莫霍面起伏的变化。数值结果表明莫霍面起伏与岩石层弹性厚度（hel）和载荷波长（λ）相关。对于相同的λ，hel越大，莫霍面起伏越小，反之亦然。而对于相同的hel，λ越大，莫霍面起伏调整到最终状态所需时间越长，其达到的幅值也越大。本文结果暗示，地幔对流形态与地表地形起伏可能并非直接相关。同时，本文结果为解释地球上存在与Airy均衡相偏离地区提供了一种可能的动力学机制。%The flow of lower crust and variation of Moho undulation under the influence of mantle convection is investigated by a quantitative model.The numerical results show the correlation between undulation of Moho and the elastic lithospheric thickness,hel,and loading wavelength,λ.For a given constant λ,the undulation of Moho is smaller when the hel is greater.It is hold conversely.For a given constant hel,the duration of adjustment of Moho undulation to the final stage is longer,and its amplitude is greater when the λ is greater.It is also hold conversely.The results imply that the pattern of mantle convection is probably not directly correlated to the topography undulation.And,the study provides a possible mechanism for explanation of the discrepancy from classical Airy-type compensation in some regions.