国家自然科学基金项目（面上项目，重点项目，重大项目）
DUAN Yi
1) Gansu Provincial Key Laboratory of Petroleum Resources, Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou, 730000; 2) School of Earth Science and Resources, Chang’an University, Xi’an, 7100543) University of Chinese Academy of Science, Beijing, 100049系统采集了位于青藏高原东北部的尕海湖淡水湖泊沉积物，对沉积物中正构烷烃及其氢同位素进行了分析，研究了沉积物中正构烷烃及其氢同位素组成，探讨了它们的来源。研究结果表明，尕海湖沉积物中正构烷烃分布反映了它们来自水生和陆生植物。尕海湖沉积正构烷烃氢同位素组成平均值为-221.9～-190.5‰。C21～C33奇碳数正构烷烃δD值明显地将样品划分为两种类型。类型Ⅰ样品的C21～C33奇碳数正构烷烃平均δD值明显地高于类型Ⅱ样品。类型Ⅰ沉积正构烷烃δD值分布特征反映了它们主要来自尕海湖水生植物；类型Ⅱ沉积物中正构烷烃δD值特征指示了它们主要来自研究区陆生草本植物。提出了具有δD值低、丰度高和CPI值低的中等链长正构烷烃起源于改造陆源草本植物的细菌。研究成果证实了沉积正构烷烃δD值可以作为指示有机质源的地球化学指标。
Sediments in Gannan Gahai lake located in the northeast of the Tibetan plateau were systematically sampled. n-Alkanes and their hydrogen isotope in these sediments were analyzed by GC-MS and GC-TC-IRMS. Compositions and origin of n-alkanes and their hydrogen isotope in the samples were studied. The distributions of n-alkanes in the samples showed that they were derived from aquatic and terrestrial plants. The mean δD values of n-alkanes in the sediments range -221.9 to～-190.5‰. The studied samples were obviously divided into two types on the basis of δD values of C21-C33 odd carbon number s. The n-alkane δD values for type 1 samples indicated that the n-alkanes come from aquatic plants in Gannan Gahai lake, while those for type 2 samples showed that they were derived from terrestrial herbaceous plants. It was considered that the medium-chain length n-alkanes with high content, low δD values and low CPI values were derived from bacteria by which sedimentary terrestrial herbaceous plants were transformed. The studied results further confirmed that n-alkanes in sediments record the hydrogen isotopic composition of source water used by organisms. Therefore, δD values of sedimentary n-alkanes can be used as geochemical indicators of paleoclimate and organic matter source.
段毅,吴应忠,赵阳.2016.青藏高原东北部尕海湖沉积物中正构烷烃及其氢同位素组成与有机质源指示意义[J].地质学报,90(5):1030-1039.
DUAN Yi, WU Yingzhong, ZHAO Yang.2016. Composition and Hydrogen Isotope of n-Alkanes in Sediments from Gahai Lake of Qinghai-Tibet Plateau, China and Their Implications for Organic Origin[J]. Acta Geologica Sinica,90(5):1030-1039.
