中国岩石圈动力学概要

本文是1:400万“中国及邻近海域岩石圈动力学图”说明书的节要。它对我国现今活动着或在新生代活动过的地质和地球物理作用过程作了综合概括,重点是板内现象,并从板块构造作用基本过程上对它们加以解释。 中国的岩石圈很不均匀。其动力学涉及8个活动亚板块和有关的17个构造块体的性质、它们的相对运动和构造应力场、以及新构造变形的特征。阐明了我国岩石圈现今运动和变形

SUMMARY OF THE LITHOSPHERIC DYNAMICS IN CHINA

This paper is a summary of the Explanatory Notes for the 1:4,000,000 scale "Lithospheric Dynamics Map of China and Adjacent Seas", which gives an overview of the geological and geophysical processes that are presently active or have been active in the Cenozoic. The focus is on intraplate phenomena and on explaining them in terms of fundamental plate tectonic processes.The lithosphere beneath China is very heterogeneous, Its dynamics concerns the nature of 8 active subplates and related 17 tectonic blocks, their relative motions and tectonic stress field, and the characteristics of neotectonic deformation. Consequently the present-day movement and deformation of the lithosphere in China, their relationship with the deep-seated processes, and the lateral heterogeneity, mass difference and stresses within it that will tend to cause movement in the future are illustrated.The intraplate tectonics and stress field are mainly controlled by the heterogeneity of the lithosphere and the mode of interaction between subplates and their boundary conditions. The collision of the Indian plate with the Eurasian plate commenced and proceeded,along the Tethys ocean side produced a strong compressional stress in western China and brings about high shear in the regions around the eastern and western corners of the Himalaya block. However eastern China is directly influenced by the Pacific side plate boundaries. The minimum prici-pal stress here is tensional, which makes the shear stress high, it may be the cause of the high seismicity in North China and southeastern China sea coast.Some features of the tectonic stress field in China are the expression of the interferences by boundary conditions along the Indian and Pacific Ocean side. The key factors that govern the formation of active structures are the mutual interaction of preexisting tectonic features, the changing geodynamic setting and the stress field.