中国大陆阶梯地貌的基本特征

本文通过中国大陆山顶面高程等值线图和大河河床高程等值线图来研究和讨论中国大陆阶梯地貌的基本特征。大致沿大兴安岭—太行山—雪峰山和昆仑山—阿尔金山—祁连山—龙门山—玉龙山—喜马拉雅山存在两条明显的山顶面高程等值线和大河河床高程等值线梯度带。它们是重要的构造地貌界线,将我国大陆分成三级由西向东逐级降低的地貌阶块。中国大陆阶梯地貌于晚期喜马拉雅运动中初具雏形。在新构造运动中,特别是发生于1.4—1.2MaB.P.的构造运动以来,使其得到进一步加强和发展。现今中国的地貌格局,主要是近100万年期间新构造运动造成的。

FUNDAMENTAL CHARACTERISTICS OF THE STEPPED LANDFORM IN CHINA CONTINENT

In this paper,the main characteristics of the stepped landform in China continent have been studied and discussed based on two maps of the altitude isolines of summit planes and major river beds. There are two obvious gradient zones of altitude isolines of summit planes and major river beds along the Daxing'anling Mountain-Taihang Mountain-Xuefeng Mountain and the Kunlun Mountain-Aerjin Mountain-Qilian Mountain-Longmen Mountain-Yu-long Mountain-Himalayas. The gradient zones serve as important tectonic morphologic boundaries as well, dividing China continent into three geomorphologic steps, getting down gradually from west to east. It seems that stepped landform had its embryonic form during the Late Himalayan movement,and got further developed through the neotectonic movement,especially the movement during 1. 4-1. 2Ma. B. P.. In a word,today's China continental morphologic framework has been formed mainly by the neotectonism in the last 1 Ma.