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| 新生代晚期青藏高原强烈隆起及其对周边环境的影响 | |
| 引用本文： | 李吉均,方小敏,潘保田,赵志军,宋友桂.新生代晚期青藏高原强烈隆起及其对周边环境的影响[J].第四纪研究,2001,21(5):381-391. |
| 作者姓名： | 李吉均 方小敏 潘保田 赵志军 宋友桂 |
| 作者单位： | 1. 兰州大学地理科学系,兰州,730000;南京师范大学地理科学学院,南京,210097 2. 兰州大学地理科学系,兰州,730000 3. 南京师范大学地理科学学院,南京,210097 |
| 基金项目： | 国家重点基础研究发展规划项目 (批准号 :G1 9980 4 0 80 9和G1 9980 4 0 81 5 )，国家自然科学基金 (批准号 :4 973 1 0 1 0 )资助重点项目 |
| 摘 要： | 青藏高原主夷平面形成的上限年龄为3.6MaB.P.,临夏盆地新生代湖相沉积同时结束,青藏运动开始,分为A(3.6MaB.P.),B(2.6MaB.P.)和C(1.7MaB.P.)3幕,A幕现代亚洲季风形成,B幕黄土开始堆积,C幕黄河出现;昆黄运动(1.2～0.6MaB.P.)使黄河干流切入青藏高原,大面积山地进入冰冻圈,可能导致中更新世之气候转型;共和运动造成黄河切穿龙羊峡,青海湖孤立,高原达到现代高度.中国三大自然区是高原隆升驱动大气环流改变而导致的中国最高层次的景观分异.本文讨论了8MaB.P.的有限高度隆升及亚洲干旱化的问题,亚洲夏季风22MaB.P.已经开始,是高原隆升及其它因素共同作用的结果,为亚洲古季风阶段.3.6MaB.P.才是现代亚洲季风真正开始的时期,可能北半球进入冰期也与此有密切关系. |
| 关 键 词： | 新生代晚期 青藏高原 构造隆升 环境变化 |
| 收稿时间： | 2001-06-29 |
| 修稿时间： | 2001年6月29日 |
Late Cenozoic intensive uplift of Qinghai-Xizang Plateau and its impacts on environments in surrounding area |
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| Affiliation: | 1. Department of Geography,Lanzhou University,Lanzhou 730000; 2. College of Geography Science,Nanjing Normal University,Nanjing 210097 |
| Abstract: | Studies on the uplift timing of Qinghai Xizang Plateau and long term climatic records in and around the Plateau hold the key to understand the mechanisms of continental collision mountain building and its coupling with or impacts on regional and global climatic changes( e.g., the formation and evolution of the Asian monsoon,drying of the Asia,global cooling,periodicity and magnitude of climatic change) in Pleistocene. The stratified landforms (planation surfaces,pediment and river terraces)and the related basin sediments recorded the whole histories of Plateau uplift and its accompanied climatic changes. These landforms and basin sediments in and along the margins of the Qinghai Xizang Plateau have been recently dated intensively by methods of paleomagnetism,fission track,K Ar,TL and 14 C,showing that the main surface on Qinghai Xizang Plateau was ended at 3.6 MaB.P. accompanied with the cessation of the Cenozoic lacustrine deposits,and suggesting the commencement of Qinghai Xizang uplift. This movement manifests itself as three phases:A,B and C,at ages of about 3.6 MaB.P.,2.6MaB.P. and 1.7MaB.P.,respectively,and accompanied accordingly with the formation of present like Asian monsoon,the beginning of Chinese loess and appearance of the Huanghe River. The Kunhuang(Kunlun Huanghe)Movement (1.2～0.6MaB.P.) caused the Huanghe River to cut back into Qinghai Xizang Plateau and raised most of mountains into geocryosphere which may lead to the Mid Pleistocene climatic shift. The Gonghe Movement(～0.15MaB.P.) has caused the Huanghe River to cut through the Longyang Gorge, isolated the Qinghai Lake and raised the Plateau to its present height. It is the uplift of Qinghai Xizang Plateau that has caused the change of the atmosphere circulation system that lead to the highest level of differentiation of the Chinese landscape,resulting in the establishment of the modern three large physiographical regions in China. The paper has dealt also with the some extent uplift at about 8 MaB.P. and Asian drying. The coming evidence shows that the East Asian summer monsoon initiated at about 22 MaB.P.,triggered by a combination of Qinghai Xizang uplift and other factors. We call this paleo Asian monsoon. Present like Asian monsoon began at 3.6 MaB.P. and is probably related closely to the onset of the Northern Hemisphere glaciation. |
| Keywords: | late Cenozoic Qinghai Xizang Plateau tectonic uplift environmental change |
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