中生代地球系统与核—幔边界动力学研究进展  

Latest Progress in the Study of the Earth System and the Core -Mantle Boundary Dynamics

作　　者：邵济安[1] 韩庆军[2] 

机构地区：[1]北京大学综合技术研究所,100871 [2]中国科学院地质研究所,北京100029

出　　处：《地质论评》1998年第4期382-388,共7页Geological Review

基　　金：国家自然科学基金(编号49672156)

摘　　要：本文介绍了90年代以来地球物理学在地球磁场方面(地球磁场古强度,地磁场极性反转频率以及真极移)的研究成果,揭示了200～100Ma全球低的地球磁场古强度;124～83Ma低的极性反转频率以及170～110Ma近乎停滞的真极移。与此同时,地球表面发生了一系列由地幔热柱上升而导致的构造热事件。它们的联系引起地球科学工作者的极大兴趣。本文介绍的两种模型,正是从核—幔边界结构演变的角度去探讨地球磁场与热场的关系。最后还从地质学的角度,提出了面临的挑战及一些值得深入探讨的地球动力学问题。In this article, advances in the study of the geomagnetic field over the last decade, especially changes in the Mesozoic geomagnetic field, are introduced. It is unveiled that during most of the Mesozoic (200~100 Ma) the paleointensity of the geomagnetic field was very low, only one-third of the mean Cenozoic value, that the geomagnetic field shows no reversals from 124 to 83 Ma, and that the true polar wander (TPW) almost remained a standstill from 170 to 110 Ma. Simultaneously, the earth surface is characterized by great unrest with many remarkable geological and geophysical processes, such as episodic mantle convection, plume activity, see-floor spreading, changes in global temperature and oil generation. The coincidence of these phenomena indicates some form of coupling among the core, mantle and earth surface activities. To comprehend the coupling, some schematic theoretical models which connect changes of the geomagnetic-field with the core-mantle boundary dynamics have been constructed in recent studies. Two main models are introduced and compared with each other. Finally, some valuable earth dynamics questions, which are the third challenge in the geoscience and need further research by geologists and geophysicists, are put forward in light of the latest progress in the study of Mesozoic geology of North China.

关 键 词：地球系统 核-幔边界 动力学 中生代 地幔柱 

分 类 号：P183.2[天文地球—天文学] P541