Magneto-and pedo-stratigraphy of paleosol-loess sequences in the Lanzhou Basin:Evidence for evolution of Huang He  

作　　者：LI Ji-Jun ZHANG Bo ZHU Jun--Jie ZHAO Zhi--Jun CAO Ji--Xiu Department of Geography. Lanzhou University, Lanzhou. 730000 China 

出　　处：《Chinese Science Bulletin》1999年第S1期119-128,共10页

摘　　要：Results of magnetopedostratigraphic study of three sections of loess in the LanzhouBasin are significant. (1) The oldest aeolian loess deposited on pediment in the Lanzhou Basindates back to 1.8 Ma, indicating the end of erosion development. (2) The highest (also oldest)terrace T7 is identified and dated at about 1.7 Ma. Huang He began developing (about 1.8-1.7 Ma)after dissection of the pediment and before the oldest terrace formed. The incision rate of HuangHe varied with time. Its two peak periods are from 1.8 to 1.7 Ma BP and from 0.15 Ma BP topresent, corresponding to episodic uplift of the Tibetan Plateau.Results of magnetopedostratigraphic study of three sections of loess in the Lanzhou Basin are significant. (1) The oldest aeolian loess deposited on pediment in the Lanzhou Basin dates back to 1.8 Ma, indicating the end of erosion development. (2) The highest (also oldest) terrace T7 is identified and dated at about 1.7 Ma. Huang He began developing (about 1.8-1.7 Ma) after dissection of the pediment and before the oldest terrace formed. The incision rate of Huang He varied with time. Its two peak periods are from 1.8 to 1.7 Ma BP and from 0.15 Ma BP to present, corresponding to episodic uplift of the Tibetan Plateau.

关 键 词：Lanzhou Basin HUANG HE TERRACE LOESS magneto-pedostratigraphy 

分 类 号：P531[天文地球—古生物学与地层学]