青藏高原北缘晚新生代的差异性隆起特征  

STUDY ON DIFFERENTIAL UPLIFT OF THE NORTH EDGE OF TIBETAN PLATEAU DURING THE LATE CENOZOIC

作　　者：马钦忠[1] 李吉均[2] 

机构地区：[1]上海市地震局,上海200062 [2]兰州大学地理科学系,甘肃兰州730000

出　　处：《地学前缘》2003年第4期590-598,共9页Earth Science Frontiers

基　　金：国家重点基础研究发展规划青藏项目(G1998040802)

摘　　要：在青藏高原的研究中,一个涉及高原隆升过程和机理的重要科学问题就是高原差异性隆升问题。文中初步研究了晚新生代以来青藏高原北缘的这种差异性隆升特征。研究表明,高原北缘山系隆升变化的差异性是很明显的。自23.7 Ma以来西昆仑山、阿尔金山和祁连山平均剥蚀率分别有4次阶梯式、谷—峰—谷—峰—谷式和二次阶梯式的变化形式。在3.6 Ma BP以前,青藏高原北缘山系的差异性隆升总体上呈现出东高西低的地貌特征;在3.6～1.7 Ma青藏运动发生期间,高原北缘山系的差异性隆升特征是西强东弱;在0.6 Ma以来,高原北缘山系的隆升差异性呈现出西强—中弱—东次强的特征。自1.7 Ma以来青藏高原北缘西昆仑山褶皱带平均缩短应变为38％,阿尔金山褶皱带平均缩短应变为8％,祁连山褶皱带平均缩短应变为15％。这和它们的高度在此期间的差异特征极为相似。The differential uplift of Tibetan Plateau is a very important topic in the study of Tibetan Plateau concerning the process of its uplift and formation mechanism. This paper primarily studies the characteristics of the uplift difference of the north edge of Tibetan Plateau during the Late Cenozoic. The results of the study show that the uplift difference is obvious in the north edge of Tibetan Plateau. The average denudation rate of the mountain system of the west-Kunlun, Altyn and Qilian has experienced the changes with the characteristics of four ladders, of valley-peak-valley-peak-valley and of two ladders respectively, since 23. 7 Ma BP. Before 3. 6 Ma BP the uplift difference of the north edge of Tibetan Plateau presented the east-high and west-low feature. During the period of the Tibetan Movement (3. 6-1. 7 Ma) the uplift difference presented the west-high and east-low feature. Since 0. 6 Ma BP the uplift difference has appeared strong in the west, weak in the middle and less strong in the east. Since 1. 7 Ma the average strain of the tectonic shortening by the squeezing action in the north mountain system of the Tibetan Plateau are 38% in the west Kunlun fold belt, 8% in the Altyn fold belt, 15% in the Qilian fold belt respectively. These characters are similar to that of the uplift difference in the altitude during the same period of time.

关 键 词：青藏高原北缘 差异性隆升 传播比 构造变形 

分 类 号：P542[天文地球—构造地质学]