Advances in Earth Science
• Articles •
Rao Zhiguo,Zhu Zhaoyu,Chen Fahu,Zhang Jiawu. Reviews on the Stable Carbon Isotopic Researches of Organic Matter of Chinese Loess[J]. Advances in Earth Science, 2006, 21(1): 62-69.
Soil stable organic carbon isotopic composition (δ13Corg) is a sensitive indicator of relative abundance of local C4/C3 plants due to the distinct distribution range of their δ13Corg and has little or no isotopic fractionation during bury and decompound process of plants. Chinese Loess Plateau (CLP), located in the northwest inner continent, is a sensitive area to climatic and environmental change and weak change of climate and environment can result in strong landscape change. So, the research on δ13Corg of Chinese loess can partly reconstruct paleovegetation type, and furthermore, indicate the relationships between climate and environment related to paleovegetation. Reviews on δ13Corg studies of Chinese loess showed: δ13Corg of Chinese loess more positive in paleosols developed during warm and moist interglacials and more positive southeastward in both paleosols and loess. The available δ13Corg data indicate the proportion of C4 plants increasing form glacial to interglacial and from the northwestern part to southeastern part of CLP. The past vegetation type of CLP determined as grassland still lack direct evidences because of all trees are also use C3 photosynthesis pathway. The key control environmental factors on C4 plants, such as temperature and Asian Summer Monsoon are still debated. Although the general rule of the distribution of Chinese loess δ13Corg is clear in both temporal and spatial sequence, some other problems including the control mechanism on Chinese loess δ13Corg are still blurry. Further understanding of Chinese loess δ13Corg needs more research work.