Late Miocene- early Pleistocene paleoclimate history of the Chinese Loess Plateau revealed by remanence unmixing

Previous studies show that the Quaternary loess sequence and the late Miocene-Pliocene red clay sequence on the Chinese Loess Plateau (CLP) share similar magnetic properties despite their being deposited under different climate conditions. To solve this paradox, we apply a novel remanence unmixing technique and demonstrate that loess and red clay on the central CLP contain a similar low-coercivity pedogenic component, but their high-coercivity components differ dramatically, reflecting different oxidation and temperature conditions. We infer that temperatures on the Chinese Loess Plateau cooled from the late Miocene to the Quaternary, in a manner similar to sea surface temperature records for the same time interval. This coherency between marine and terrestrial records argues for a CO2 forcing on long-term paleoclimatic variations. Key Points Backfield remanence data of Chinese loess and red clay consist of two components Loess and red clay have similar pedogenic but different detrital components The Loess Plateau experienced a cooling trend from the late Miocene to the Quaternary