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

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.