Magnetostratigraphic record of the Late Miocene onset of the East Asian monsoon, and Pliocene uplift of northern Tibet

Widespread eolian red clay underlying the Plio-Pleistocene loess-palaeosol succession in northern China has been dated magnetostratigraphically back t o 8.35 Ma, indicating that the East Asian monsoon started at about the same time as the Indian monsoon. An initial sedimentation rate of 11 m/Myr incr eased gradually to 17.5 m/Myr by 6 Ma, and then decreased to 6 m/Myr betwee n 5 Ma and 3.5 Ma. A marked increase in sedimentation rate and grain size b eginning between 3.5 Ma and 3.1 Ma indicates that the East Asian winter mon soon strengthened at this time, and intensified further after 2.6 Ma. The t emporal coincidence of the stronger winter monsoon and the Pliocene uplift of northwestern Tibet just before the onset of the Northern Hemisphere glac iation indicate that the three events could be causally linked. (C) 2001 Pu blished by Elsevier Science B.V.