Pathways of dust input to the Chinese Loess Plateau during the last glacial and interglacial periods

Abstract

It has been established that loess deposited on the Chinese Loess Plateau was derived from arid and semi-arid regions in north and northwest China, but the specific pathways of dust transport are still not proved. In this study, 32 loess–palaeosol profiles of the last glacial and interglacial periods were measured for magnetic susceptibility in order to investigate the dust transport pathways of dust input to the Loess Plateau. The magnetic susceptibility variations of the loess–palaeosol deposits within the last glacial cycle can be correlated with marine oxygen isotope variations to estimate the ages of boundaries of the loess units and intercalated palaeosols. The sedimentation rate of each depositional unit can be obtained by dividing the thickness by the time that it represents. Because sedimentation rates decrease downwind from the dust source, the spatial distribution of dust sedimentation rates shows that northwest and west winds were the two most important agents for transport of dust to the Loess Plateau during the last glacial cycle. The north and northeast winds played an almost negligible role. In addition, topography and dust from local sources strongly affected the dust accumulation rates at some measured sites.