岩石圈热—流变结构与大陆动力学

THE CONTINENTAL DYNAMICS RELATED TO THE THERMAL-RHEOLOGICAL STRUCTURE OF THE LITHOSPHERE

由于大陆内部存在上千公里宽的弥散边界变形带 ,板块构造理论用于解释新生代大陆内部的显著的构造变形遇到了困难。因此 ,探讨大陆岩石圈的构造变形机制、演化及动力学过程从而成为国际地球科学的热点研究领域———大陆动力学。大量的地震测深、地震层析成像技术的应用对岩石圈的精细结构研究 ,已揭示岩石圈结构和物质组成存在显著的横向非均质性。这种横向非均质性是地质时期内大陆岩石圈经历多期次构造—热事件叠加与改造所形成的。同时 ,也决定了岩石圈热—流变学结构的横向分块、纵向分层的特性。大陆岩石圈热—流变学结构非均质性及其构造继承性对大陆内部构造变形起控制作用。所以 ,大陆动力学应注重开展大陆变形的运动学、大陆岩石圈的热—流变学结构和大陆变形的地球动力学数值模拟研究。

The difficulty is met in the explanation of continental deformation in Cenozoic by means of plate tectonics model, due to the existence of obvious diffuse plate boundary deformation zones with over thousands kilometers wide inside continents. Which gives birth to the new frontier of international earth science communities-continental dynamics, focusing on the deformation mechanism, evolution and dynamic process of the continental lithosphere. Many geophysical techniques including Deep Seismic Souding and Seismic Tomogrpahy have been applied widely to reveal the fine structure of lithosphere, indicating the prominent lateral heterogeneities of structure and composition within continental lithosphere. The heterogeneity of continental lithosphere derived from episodic superimposition and alternation of tectono-thermal events during its long geological history, then again induces the thermal-rheological structure of lateral heterogeneity and vertical stratification. Here we propose that the heterogeneity of lithospheric thermal-rheological structure and tectonic inheritance are the controlling factors for intracontinental deformation. Kinematics and geodynamic modeling of continental deformation, along with thermal-rheological structure of the continental lithosphere are all emphasized here for study in future.