中国中、新生代沉积盆地类型与演化

我国中、新生代沉积盆地形成于不同的地质背景中,印支期古特提斯洋闭合,印支褶皱带以北出现了陆相盆地,南方上扬子区出现残留海盆。燕山期、喜山期随着中特提斯、新特提斯洋相继关闭,使原有的大型盆地得到改造,形成一系列新生的沉积盆地。这些盆地形成的构造环境各不相同,可由板块或块体的边界系统的地球动力学环境来划分。这些环境分别形成裂谷型裂陷盆地、造山型压陷盆地,以及剪切型拉分盆地等。如以盆地构造特点可分为坳陷盆地和断陷盆地。随着地质历史的发展,不同时期板块或块体所处的地球动力学环境也在发生变化。因此,某些盆地形成以后,其力学性质多次发生变化,不仅表现在盆地边界的力学性质转化上,而且表现在不同阶段不同类型的盆地相互叠加,从而使我国中、新生代沉积盆地具有许多独特新颖的构造类型;建立这些盆地演化的模型,可为研究岩石圈构造变形及能源矿产分布规律提供依据。

THE TYPES AND EVOLUTION OF MESOZOIC-CENOZOIC SEDIMENTARY BASINS IN CHINA

The Mesozoic-Cenozoic sedimentary basins in China are developed in the different geological settings.During Indo-Chinese epoch,nonmarine basins were generated in the north of Indo-Chinese folded belt but remn-ant sea basins developed in the western part of Yangtze area in Southern China as Palaeo-Tethys Ocean became vanished.During Yanshan period and Himalayan period,the old basins were deformed as Meso-and Neo-Te-thys became terminated,and a number of newly-developed basins formed in these different tectonic settings.These settings can be classified into three kinds according to the geodynamic settings of plate or block boundary system,that is,extensional-rifted setting with divergent boundary system; orogenic setting with convergent boundary system,shear-extentional or shear-compressional setting with stike-slip transform boundary system.Rift-rifted basin,mountain front basin and intermountain compie-ssional-depression basin as well as pull-agart basin were generated respectively in these settings.Based on basin structure characteristics,we can group these basins into two classes,namely depression and faulted basin.In fact,faulted basin includes two kinds of strctural types: rifted basin and compressional-faulted basin; pullagart basin belongs to faulted structure.Geodynamic settings of plates or blocks,however,would be different in the different periods.Therefore,the dynamic characteristics of some basins would have changed several times,which can be reflected not only on the changes of their force characteristics,but also on the superimposition of different types of basins at the different stages.This makes that Mesozoic-Cenozoic basins in China have many unique types.The evolution models of these basins can be developed through careful studies,which can lay a foundation for the study of tectonic deformation of lithosphere and the distribution of mineral as well as that of energy resource.