Abstract:

There is a land of around 1500000 km2 in north China covered by sand and loess deposits, and the sandloess deposition system is venerable in response to climatic changes and human disturbance. However, to quantificationally separate which one, the climatic change or the human activity, is dominate driver of deposition and erosion of the sand and loess sediments, is still an open question. In this study, we summarize ages of optically stimulated luminescence dating of the sand and loess sediments, employ geostatistic and remote sensing methods, and collect modern observation data of dust fall and surface erosion, to investigate deposition and erosion process in the past, and their possible responses to climatic changes and human activity in the future on the sandloess system.  Based on these interdisciplinary data synthesis, we suggest that climatic change is the most important force to control deposition and erosion of the sand and loess deposits in north China, and that the sandloess region is both the source and the sink of dust, depending on climate and surface structure. The loess deposit is a more complete palaeoclimatic archive than the sand deposits. The loess erosion in Chinese Loess Plateau commenced in the geological time; the human activity has accelerated the surface erosion, but it did not substantially change the erosion. Under the global warming scenario, the intensified evaporation in the sandloess region probably may exceed the increase of the monsoon precipitation, causing drying of the sand fields. A drying sand field will strengthen dust activity and increase dust sedimentation rate in the Loess Plateau.

Key words: the sandloess system, deposition and erosion, climatic changes, human activity, North China