Variations of surface soil δ~(13)C_(org) in the different climatic regions of China and paleoclimatic implication

摘要

Knowledge of relationships between organic carbon isotope composition (delta C-13(org)) of surface soils and climatic factors (precipitation and temperature) is very crucial to reconstruct the paleoclimate variations. Relationships relating delta C-13(org) and climatic factors remain relatively different in the regions influenced by various climatic systems. In this study, based on compiled 1394 surface soil delta C-13(org) data in China, the relationship between soil delta C-13(org) and precipitation and temperature are statistically investigated in the different climatic regions of China (i.e., Xinjiang region, Tibetan Plateau, northern China and southern China). The result show that, spatially, surface soil delta C-13(org) values in Xinjiang region are mainly controlled by temperature and precipitation, while that are mainly controlled by precipitation in Tibetan Plateau. Surface soil delta C-13(org) in northern China and in southern China are mainly influenced by temperature but with a contrary picture. Temporally, a decrease of Holocene delta C-13(org) in Xinjiang region was caused by reducing temperature and increasing precipitation, while an increase of delta C-13(org) in Tibetan Plateau was a response to reducing precipitation. A decrease of Holocene delta C-13(org) in northeast China resulted from temperature decreasing and that in Loess Plateau from temperature decreasing and C-4 abundance reducing. In southern China, temperature decreasing since Holocene was responsible for an increasing trend of delta C-13(org) sequence. Our results can be considered as a basis for the past climate and vegetation interpretation of delta C-13(org) data inferred from various geological archives in the different climatic regions of China.