Red Clay Sediment in the Central Chinese Loess Plateau and Its Implication for the Uplift of the Tibetan Plateau  

作　　者：SONG Yougui LI Jijun FANG Xiaomin XIA Fei DONG Hongmei 

机构地区：[1]State Key laboratory of Loess and Quaternary Geology, InsHtute of Earth Environment, Chinese Academy of Sciences, Xi＇an 710075, China [2]MOE National Laboratory of Western China＇s Environmental Systems ＆ Department of Geography, Lanzhou University, Lanzhou 730000, China [3]Department of Geosciences, East China Institute of Technology, Fuzhou 344000, China [4]Xi＇an University of Science and Technology, Xi＇an 710054, China

出　　处：《Journal of Mountain Science》2005年第2期137-145,共9页山地科学学报（英文）

基　　金：supported by the National Natural Science Foundation of China(NO:40202019,90102017,40121303);National Basic Research Program of China(2004CB720202);China Postdoctoral Fund

摘　　要：The widely distributed red clay sediment underlying the Chinese Loess Plateau truly records the Neogene environmental evolution, and its genesis and development are intrinsically related to the uplift processes of the Tibetan Plateau and the evolution of East Asia monsoon system. In this paper, a detailed magnetostratigraphy of a loess-red clay section （107°13′E, 35°02′N） from the central Loess Plateau is reported. The loess-red clay sequence is composed of 175 m Quaternary loess-paleosol sequence and 128 m Neogene red clay sediments. Based on the correlation with the standard geomagnetic polarity time scale, the paleomagnetic results indicate that the age of Chaona red clay sequence extends to 08.1 Ma, which is the older red clay deposition in the central Chinese Loess Plateau. The commencement of red clay at -8.1 Ma may imply that the Ordos planation surface was broken by the movement of the Haiyuan-Liupanshan Faults, which was related to the uplift of the Tibetan Plateau induced by the collision of India Plate and Eurasian Plate. And the western part adjacent to the Tibetan Plateau was uplifted to form the embryo of the Liupan Shan （Mts.） and the eastern part was down-faulted to receive red clay deposition. We link this faulting to an initial uplift of the Tibetan Plateau. The undulating nature of the broken Ordos planation surface may explain the chronological differences and depth discrepancies among various cross-sections of red clay.

关 键 词：Loess-paleosol red clay sequence MAGNETOSTRATIGRAPHY planation surface geological significance 

分 类 号：P942[天文地球—自然地理学] P941.74