Dating and genesis of the upper Weihe River terraces in Longxi basin,China

作     者：Pan Baotian, Liu Xiaofeng, Gao Hongshan, Wang Yong and Li Jijun(Key Laboratory of Western China’s Environmental System, Ministry of Education, Lanzhou University, Lanzhou 730000, China) 

作者机构：Key Laboratory of Western China's Environmental System Lanzhou University Lanzhou 730000 China 

出 版 物：《Progress in Natural Science:Materials International》 (自然科学进展·国际材料(英文))

年 卷 期：2007年第17卷第11期

页      面：1334-1340页

核心收录：

学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学] 

基　　金：Supported by National Natural Science Foundation of China ( Nos 40401007,40471016 ,40421101) the National Programon Key BasicResearch Project (No 2005CB422001) 

主　　题：loess stratigraphy river terraces climate change Upper Weihe River 

摘      要：Seven terraces along the Weihe River in Longxi basin have been investigated. These terraces all consist of archetypal duality in structure, namely the floodplain deposits and the layer of gravels overlaid by varying thickness of the loess. By resorting to various dating approaches such as palaeomagnetic, optically stimulated luminescenece (OSL), 14C and loess-paleosol sequence, we provide preliminary timing of these seven terraces along upper Weihe River. Analysis on sedimentation characteristics and dating of these terraces showed that seven terraces may be jointly generated by tectonic uplifts and climatic changes. Tectonic uplifts may accommodate initial river incision, and climatic change may be responsible for processes of subsequent channel widening and aggradation. Aggradation normally occurs during glacial periods, in contrast to down-cuttings during transitions from glacial to interglacial period. Moreover, on the basis of the timings and heights of these terraces, we infer that the long-term rate of river incision was determined to be 0.2 m/kyr during the last 870 kyr, which differs from other river incision rates. This discrepancy may reflect spatio-temporal differentiation of tectonic activities in the Qinling orogenic belt during the Pleistocene.