Isotopic and pollen evidence of paleo-vegetation changes in loess plateau of Luochuan, China

Abstract

Carbon isotopes in loess through S₀ to S₁₁ at Luochuan section in Shanxi province, China were studied. The curve of δ¹³C compares well to that of the oxygen isotope in deep sea sediments from Deep Sea Drilling Project Site 607 drill hole. There is a negative peak of δ¹³C within S₅ paleosol where the content of δ¹³C is -16.615⁰/₀₀, shows that the climatic of that period is optimum, and the vegetation is likely forest. Compared with the pollen analysis, we conclude that the vegetation type of palesol S₀,S₁,S₄,S₈,S₉, whose δ¹³C content is -5.85--10.00⁰/₀₀, is forest-grass. The d13C content of paleosol S₂, S₃, S₆, S₇ is -8.72~-6.95⁰/₀₀, and their vegetation is grass. The loess layer L₁, L₂, L₅, L₆, L₈, L₉ represent the severe cold-dry glacial period with the δ¹³C content of -3.7- -2.27⁰/₀₀, and their vegetation belongs to steppe-desert. The research of paleo-vegetation type is significant to anti-soil erosion in the loess plateau of China.