Long-chain alkenones in sulfate lakes and its paleoclimatic implications  

作　　者：SUNQing CHUGuoqiang LIShengqiang LUCaifen ZHENGMianping 

机构地区：[1]NationalResearchCenterofGeoanalysis,Beijing100037,China [2]InstituteofGeologyandGeophysics,ChineseAcademyofSciences,Beijing100029,China [3]CenterforAnalysisandPrediction,CSB,Beijing100036,China [4]InstituteofMineralResourcesandOpenLaboratoryofSalineLakeResourcesandEnvironment,ChineseAcademyofGeologicalSciences,Beijing100037,China

出　　处：《Chinese Science Bulletin》2004年第19期2082-2086,共5页

摘　　要：The proxy of U37 index is widely applied to K ’ reconstructing paleotemperature in the marine environment. However, the long-chain alkenones (LCAs) research is rarely reported in the liminic system. In this paper, we studied LCAs in the surface sediments (0 —10 cm) of nine sulfate lakes in the Inner Mongolia Autonomous Region, Xinjiang Uygur Autonomous Region and Qinghai Province, China. LCAs are detected in eight of the nine lakes, except a dry salt lake —Lake Lop. The result shows that LCAs might be uni- versal in the sulfate lakes. In most of the surface samples, the sequence of the abundance of the long-chain alkenones is C37>C38>C39>C40. And C37︰4 methyl ketone is a predominant compound in the C37 alkenone homologue. Based on regres- sion analysis of U37 -ratios and the average annual, seasonal K ’ (spring, summer, autumn, winter) temperatures, the linear K ’ relativity of U37 -ratios and mean annual temperatures is superior to the others, and the correlation coefficient is 0.88 (r2 = 0.88). The linear relationship of U37 and the average K ’ annual temperature in different water chemistry environ- K ’ ments suggests that the mechanisms controlling U37 index in the saline lakes might be the same as those in the ocean environment. The alkenone unsaturation could become an important paleotemperature proxy in the lacustrine envi- ronment.The proxy of U37 index is widely applied to K ' reconstructing paleotemperature in the marine environment. However, the long-chain alkenones (LCAs) research is rarely reported in the liminic system. In this paper, we studied LCAs in the surface sediments (0 —10 cm) of nine sulfate lakes in the Inner Mongolia Autonomous Region, Xinjiang Uygur Autonomous Region and Qinghai Province, China. LCAs are detected in eight of the nine lakes, except a dry salt lake —Lake Lop. The result shows that LCAs might be uni- versal in the sulfate lakes. In most of the surface samples, the sequence of the abundance of the long-chain alkenones is C37>C38>C39>C40. And C37︰4 methyl ketone is a predominant compound in the C37 alkenone homologue. Based on regres- sion analysis of U37 -ratios and the average annual, seasonal K ' (spring, summer, autumn, winter) temperatures, the linear K ' relativity of U37 -ratios and mean annual temperatures is superior to the others, and the correlation coefficient is 0.88 (r2 = 0.88). The linear relationship of U37 and the average K ' annual temperature in different water chemistry environ- K ' ments suggests that the mechanisms controlling U37 index in the saline lakes might be the same as those in the ocean environment. The alkenone unsaturation could become an important paleotemperature proxy in the lacustrine envi- ronment.

关 键 词：U37^K 古温 温度测定 古气候 长链烯酮 硫酸盐湖 

分 类 号：P941.78[天文地球—自然地理学] P332.6[天文地球—水文科学]