NOAA/WDS Paleoclimatology - Chaona, Chinese Loess Plateau Late Neogene Magnetic Susceptibility Data

The Late Cenozoic red clay-loess sequence in the Chinese Loess Plateau provides a high-resolution record of paleoclimatic and tectonic changes related to the phased uplift of the Tibetan Plateau. Detailed magnetostratigraphy of a recently recovered 125-m-thick sediment sequence from the central Chinese Loess Plateau shows that the red clay began to accumulate at ca. 8.1 Ma, implying a marked drying in the interior of Asian as well as the initial establishment of the East Asian paleomonsoon regime. Prior to 3.8 Ma, the ferromagnetic mineral concentrations, as revealed by both magnetic susceptibility and S-ratios, exhibit a cyclic pattern superimposed upon a linear trend. This pattern collapsed immediately after 3.8 Ma, suggesting a change in source area. This in turn may have resulted from the reorganization of atmospheric circulation and the onset of the modern Asian monsoon, probably associated with the accelerated uplift of the Tibetan Plateau to a certain threshold elevation.