Variations of surface soil δ13Corg in the different climatic regions of China and paleoclimatic implication

Abstract

Knowledge of relationships between organic carbon isotope composition (δ13Corg) of surface soils and climatic factors (precipitation and temperature) is very crucial to reconstruct the paleoclimate variations. Relationships relating δ13Corg and climatic factors remain relatively different in the regions influenced by various climatic systems. In this study, based on compiled 1394 surface soil δ13Corg data in China, the relationship between soil δ13Corg 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 δ13Corg values in Xinjiang region are mainly controlled by temperature and precipitation, while that are mainly controlled by precipitation in Tibetan Plateau. Surface soil δ13Corg in northern China and in southern China are mainly influenced by temperature but with a contrary picture. Temporally, a decrease of Holocene δ13Corg in Xinjiang region was caused by reducing temperature and increasing precipitation, while an increase of δ13Corg in Tibetan Plateau was a response to reducing precipitation. A decrease of Holocene δ13Corg in northeast China resulted from temperature decreasing and that in Loess Plateau from temperature decreasing and C4 abundance reducing. In southern China, temperature decreasing since Holocene was responsible for an increasing trend of δ13Corg sequence. Our results can be considered as a basis for the past climate and vegetation interpretation of δ13Corg data inferred from various geological archives in the different climatic regions of China.