岩石圈弯曲的黏弹性松弛及其对确定弹性岩石圈厚度的影响  

Viscoelastic relaxation of lithospheric flexure and its influence on determining thickness of elastic lithosphere

作　　者：邵翠法 王世民 SHAO Cuifa;WANG Shimin(Key Laboratory of Computational Geodynamics of Chinese Academy of Sciences,College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院大学地球与行星科学学院中国科学院计算地球动力学重点实验室,北京100049

出　　处：《中国科学院大学学报（中英文）》2020年第5期640-649,共10页Journal of University of Chinese Academy of Sciences

基　　金：国家自然科学基金(41374090,41674086)资助。

摘　　要：确定弹性岩石圈厚度在地球科学中具有重要意义。基于弹性板弯曲解析解结合岩石圈弯曲外缘隆起位置反演弹性岩石圈厚度的传统方法具有深远影响。利用变黏度可压缩黏弹性有限元模型定量研究岩石圈在表面垂向载荷作用下弯曲的黏弹性松弛问题。模拟结果显示,外缘隆起位置具有先向弯曲中心运动而后向弯曲外侧移动的特点,反向运动发生在载荷作用约9 Ma后。与基于松弛时间定义的弹性岩石圈厚度相比,基于弹性板弯曲解由外缘隆起位置约束弹性岩石圈厚度的方法仅在载荷作用后0.2~5.0 Ma的时间段内给出较为合理的结果。It is of significant importance to determine the thickness of elastic lithosphere in geoscience.The traditional method of inverting the thickness of elastic lithosphere constrained by the location of peripheral bulge in the flexural lithosphere based on the analytical solution of elastic plate flexure has far-reaching influence.In this work,the viscoelastic relaxation of the lithosphere flexure under vertical surface loads is studied quantitatively by means of a compressible viscoelastic finite element model with variable viscosities.The simulation results show that the position of the peripheral bulge moves first to the bending center and then to the outside of the bending,and the reverse motion occurs about 9 Ma after the loading.Compared with the elastic lithospheric thickness defined by relaxation time,the method of determining the thickness of the elastic lithosphere by the position of the peripheral bulge based on elastic plate bending solution gives reasonable results only in the period of 0.2-5.0 Ma after loading.

关 键 词：岩石圈弯曲 弹性岩石圈 黏弹性松弛 数值模拟 

分 类 号：P31[天文地球—固体地球物理学]