Organism Records of Holocene Peat nAlkanes in the Northeastern QinghaiXizang Plateau

Key words: 
• the northeastern Qinghaixizang Plateau

Abstract: The distribution of the nalkanes in the Hongyuan peat core of the northeastern Qinghaixizang Plateau was systematically analyzed based on the GCMS analysis. The organism records during the Holocene were reconstructed in this region. The regular variation between the dominant C25 and C31 nalkanes concentration in the peat core reveal that the peat swamp possibly occur the replacement of the morphologically based species or the chemicallybased species during the Holocene. This replacement might be the result of climatic change. When the climate fluctuates largely, the swamp possibly appears the replacement between aquatic plants and the terrestrial plants; On the contrary, when the climate has a small variation, the chemicallybased species will present replacement. The results are compared with pollen records in the same region. The discrepancy between the nalkanes and pollen records was analyzed. One of reason is the nalkanes mainly record the composition of plant debris deposited locally, the pollen assemblage is more an average signal of the flora over a wider area. The results give a new proof for the biology information of the Holocene in the QinghaiXizang Plateau. The author also proposes lipid biomarkers (such as nalkanes) can be viewed as the effective tool of vegetation reconstruction, together with the pollen, and will gain the detailed vegetation evolution history.