Palaeoclimatic and sedimentary history from magnetic susceptibility of loess in China

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Abstract
The magnetostratigraphic age of the oldest loess sediments in the central Chinese loess plateau investigated so far has recently been placed at ca. 2.4 million years B.P. Thus, glaciations in Central Asia, which are believed to provide the detritus for the formation of Chinese loess, commenced at the same time as the first ice‐rafted debris sank into the ocean basins of the northern hemisphere [Shackleton et al., 1984], Lithologic, palaeontologic, geochemical and especially rock‐magnetic variations throughout the loess column are indicative of palaeoclimatic fluctuations during loess deposition. The variations of magnetic low field susceptibility in loess closely resemble those of the marine oxygen‐isotope record [Shackleton and Opdyke, 1976] and establish for the first time a continuous record of the Pleistocene glacial and interglacial stages in a continental section. Spectral analysis of the rock‐magnetic time series indicates slow apparent sedimentation during interglacial periods which are characterized mainly by calcium dissolution and related compaction of the soils. Variable aeolic sediment influx as well as erosion and/or polygenetic soil formation may also strongly influence the sedimentary history.