Holocene sediment-accumulation rates in the western Loess Plateau, China, and a 2500-year record of agricultural activity, revealed by OSL dating

High-resolution optically stimulated luminescence (OSL) dating of a terraced loess section in the western margins of the Chinese Loess Plateau provides evidence of continuous and varying accumulation of dust throughout the Holocene. From 12030 to 2500 years ago, the sediment-accumulation rate was approxi mately 0.2 mm/year. After this time, it increased to approximately 0.8 mm/year, during a historically docu mented period of agricultural expansion in adjacent areas. From 680 years ago, a further increase in accumu lation rate, to approximately 3.4 mm/year, is evident. Particle-size analysis indicates that this increase in accumulation rate was associated with anthropogenic addition of sandy sediment, probably for soil improve ment. The OSL dating also identifies the period when the terrace was first cut for agricultural use, between 2500 and 2070 years ago.