Environmental and rock magnetic studies of rapid fluctuations of Asian summer monsoon during the last interglacial maximum (MIS 5e)

A systematic environmental rock magnetic study of a century-millennial scal e loess-paleosol sequence of the last interglacial in the Jiuzhoutai well s ection, Lanzhou, on the western Loess Plateau demonstrates that Asian summe r monsoon experienced fast and large oscillations manifesting as three peak s and two valleys lasting about 1-2 ka. Valley 4 with a central age of 120. 5 ka is the most evident, suggesting that summer monsoon was weakened nearl y to a level in glaciations. This indicates that summer monsoon has a natur e of instability in century-millennial scale change in the last interglacia l.