上通流对大陆岩石圈地幔-地壳热结构模式的潜在影响  

Potential effects of upward throughflow on thermal structure models within the continental lithospheric mantle-crust

作　　者：林舸[1] 赵崇斌[2,3] B.E.HOBBS 张露[4] 周叶[1] 

机构地区：[1]中国科学院边缘海地质重点实验室,广州地球化学研究所,广州510640 [2]中南大学计算地球科学研究中心,长沙410083 [3]CSIRO Exploration and Mining,PO Box 1130,Bentley WA6102,Australia [4]中国科学院遥感应用研究所,遥感信息科学重点实验室,北京100101

出　　处：《地球物理学报》2008年第2期393-401,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(NSFC-40773004);中国科学院知识创新工程方向性项目(kzcx2-yw-128-04);中国科学院边缘海地质重点实验室课题(MSGL04-8)资助

摘　　要：本文以多孔介质中大尺度传热问题为基础,结合热平衡理论分析与数值计算,探讨了上通流对大陆岩石圈地幔-地壳热结构模式的潜在影响.根据大陆岩石圈中孔隙波传热概念模型的初步理论分析结果,指出了采用理论分析和数值模拟相结合的方法在研究大陆岩石圈地幔-地壳热结构模式时的重要性.理论分析方法可用来确定岩石圈尺度范围内大陆岩石圈的厚度和大陆地壳相关的边界条件,从而为地壳范围内数值模型的建立提供一些重要信息.数值模拟方法可以用来模拟地壳尺度范围内地壳的详细结构和复杂几何形状.如果地壳内的热分布是所考虑的主要因素,采用具有地壳尺度的合理数值模型可以有效减少计算机工作量.利用理论分析方法求出的岩石圈尺度范围内大陆岩石圈厚度与地幔传导热流之间关系的理论解,不仅可以用来验证模拟大陆岩石圈内传热问题所采用的数值方法,而且可以用来初步研究大陆岩石圈内热分布的基本规律,为研究岩石圈地幔热事件中大陆岩石圈热减薄过程提供相应的边界条件.本文从理论分析的观点初步探讨了中国大陆不同构造背景下大陆岩石圈的热结构模式,其结果与从地球物理和地质资料中获得的大陆岩石圈热结构模式十分吻合.研究结果表明由大陆岩石圈中孔隙波传播所导致的上通流是影响大陆岩石圈地幔-地壳热结构模式及大陆岩石圈地幔与地壳之间物质和能量交换的可能机制之一.Heat transfer problems between the lithospheric mantle and crust are similar to large-scale heat transfer problems in porous media. The main purpose of this paper is to investigate the potential effect of upwardthroughflow on the thermal structure model within the continental lithospheric mantle-crust. Based on the preliminary theoretical results from the porosity-wave induced heat-transfer and mass-transport model, it is indicated that it is important to use a combination of theoretical and numerical approaches for solving lithospheric mantle-crust heat transfer problems. The theoretical approach is used to determine the thickness and the related boundary conditions of the continental crust at the lithospheric scale, so that some important information can be provided accurately for establishing a numerical model of the crustal scale. On the other hand, the numerical approach can be used to simulate the detailed structures and complicated geometries of the continental crust at the crustal scale. If the thermal distribution in the crust is of the primary interest, the use of a reasonable numerical model at the crustal scale results in a significant reduction in computer efforts. Not only can the analytical solutions for the relationship between the continental lithosphere thickness and the mantle conductive heat flux at the lithospheric scale be useful for validating numerical methods in dealing with lithosphere-scale heat transfer problems, but also they can be used to investigate the fundamental issues related to thermal distributions within the continental lithosphere. Thus, these analytical solutions can provide correct thermal boundary conditions for numerically solving lithosphere thermal-thinning problems associated with mantle thermal events. Good agreement between the thermal structure types obtained from the present analytical solutions and those obtained from the geophysical and geological observations indicates that the generation and propagation of porosity waves are one of the potential mechanisms fo

关 键 词：热结构 热传递 上通流 岩石圈地幔一地壳 

分 类 号：P314[天文地球—固体地球物理学] P541[天文地球—地球物理学]