Environmental Evolution Records of Biomakers from Lacustrine  Deposits of Xingyun Lake Yunnan

Key words: 
• recent environmental evolution /
• lipids /
• nalcohols /
• lacustrine deposits /
• Xingyun Lake

Abstract: A 76 cm core was drilled from Xingyun Lake, in the center of Yunnan Province, southwest China, to get the environment change record. Using GCMS analysis, a series of lipids, including nalkanes, nalkanoic acids and nalcohols, have been identified. This paper focuses on nalcohols in this core. Result shows that the distinct nalcohols distributions in different depth. The chromatographic peak of most of the samples are identified according to carbon number (arrangement) in double peak, in which the former and back main peak carbons are C16 and nC26, respectively; the evenodd carbon predominance both in the lower and higher carbon number nalcohols. The carbon number components of lower and higher are in the relative balance at 76~ 60 cm, dominated by higher at 60~38 cm, the higher present in less abundance at 38~12 cm and the lower show greater abundance at 12~0 c m depth. The rate of the higher carbonate components to the lower (Rl/h ) are between 0.13~4.1 , which have marked corresponding relation to the temperature curve under the less human effect. Four climate stages can be divided according to the records since about 130 a, i.e. cool period before 1920 ,warm period between 1920~1956 with the warmest period in 1940s′, cold period between 1957~1970s and warm period 1980s. Since 1993 Rl/h increase may record the euotrophic history of the lake. The carbon preference index (CPI) reveals the organic origin of the lake has some alternations. More attention must be paid to that the high effected by the euotrophic which may lead the the high Rl/h.The lipids are sensitive to the environment evolution. However, further and more detailed work should be done for better understanding the relationship between environment evolution and Lipid records.