Variations in loess and palaeosol properties as indicators of palaeoclimatic gradients across the Loess Plateau of North China

New data are presented on micromorphology, magnetic susceptibility and particle size characteristics of three soil/sediment units at four locations along a WNW-ESE transect across the Loess Plateau of North China. Differences and spatial trends are used to assess the sensitivity of such data as proxies of regional palaeoclimatic gradients. The steepest climatic gradient suggested by the magnetic susceptibility for the S1 palaeosol is at the eastern (humid) end of the traverse. Micromorphology and particle size analysis show that the loess units in the east are richer in clay than the best developed palaeosols in the semi-arid west, and that particle size in the west appears to provide a more sensitive record of climatically-driven changes than magnetic susceptibility. The use of surface and near-surface soils as a datum for inferring palaeoprecipitation values is reviewed in the light of recent evidence of substantial degradation of such soils. Micromorphological and particle size analysis of closely spaced samples from loess-palaeosol sequences is a sensitive addition to magnetic susceptibility stratigraphy and correlation.