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系统地分析了中国柴达木盆地察尔汗湖贝壳堤剖面中的生物标志化合物,在古湖泊沉积中检测出含季碳的长链支链烷烃A~C系列化合物,分别被确定为5,5-二乙基烷烃、6,6-二乙基烷烃、5-丁基,5-乙基烷烃系列,它们的相对丰度表现为A>B>C.根据A,C系列为奇数碳分布,B系列为偶数碳分布,A系列的高值区域对应于B和C系列的高值区域的特征,认为A,B和C来自相同生物源.根据在剖面下部A系列丰度较低,而在剖面上部湖泊咸化过程中A系列丰度较高来判断,该系列化合物来自更适宜湖泊咸化过程中所存在的某种喜热的菌藻类.从研究剖面变化趋势来看,湖泊早期输入的有机质成熟度较高,A系列C23为主峰,湖泊发育和晚期低成熟有机质比较丰富,其主峰碳有向高碳数转移的趋势.在剖面中A25/nC25比值在湖泊发育过程中其相对丰度存在明显差异,反映了柴达木盆地该阶段湖泊演化过程与气候环境的特殊性,表明这类支链烷烃的分布特征可能记录了湖泊演化历史过程中的环境信息,这对恢复与重建剖面记录的气候环境具有十分重要的意义.
The biomarkers in the shell dike Chaerhan Lake of Qaidam Basin in China were systematically analyzed. A ~ C series of long chain branched paraffins containing quaternary carbon were detected in the sediments of ancient lakes, and were identified as 5, 5-Diethyl Alkane, 6,6-Diethyl Alkane, 5-Butyl, 5-Ethylalkane series, their relative abundances are expressed as A> B> C. According to A, the C series is an odd number carbon distribution , The B series are even carbon distributions and the high values of the A series correspond to those of the high values of the B and C series and A, B and C are from the same biological source.According to the lower abundance of the A series in the lower part of the profile Judging from the higher abundance of A series in the lakes salinization process in the upper part of the profile, this series of compounds are from a more thermophilic algae and algae that are more suitable for lake salinization. The A25 C23 was the main peak, and the lacustrine lake developed and the late low mature organic matter was rich, and the main peak of carbon had the trend of high carbon carbon transfer. The A25 / nC25 ratio in the lake was relatively high in the lake development There is a significant difference in degree, reflecting the evolution of the lake and gas at this stage of the Qaidam Basin The special nature of the environment, suggesting that distribution of such branched alkanes may record the information environment lake evolution historical process, which is of great significance for the rehabilitation and reconstruction profile records climate.