Spatial climatic variability on the Central Loess Plateau (China) as recorded by grain size for the last 250 kyr

At 10 locations on the Central Loess Plateau (CLP), the grain-size distribution of the loess was analysed in order to increase our understanding of the dynamics of the aeolian system that was driving the deposition of the huge amounts of loess. We focused on the upper 18 to 40 m of the loess sections representing the previous 250 ky. After chronostratigraphical subdivision of each section, the grain-size variations of the different loess sections have been compared with each other in two north–south transects. As a result, the regional variability of the grain size over the Central Loess Plateau is obtained for different periods in the last 250,000 years. This variability is linked to both climatic changes and topographic characteristics. Steep grain-size gradients were present during glacial periods with very large variation in deposition quantity, while dust deposition over the Plateau was much more uniform during interglacial periods, with regard to both grain size and dust flux. It means that the dust deposition was very sensitive to climate variations in the northern part of the Central Loess Plateau. In contrast, the variability in loess deposition between glacials and interglacials was decreasing towards the south.