察尔汗盐湖正构烷烃和单体碳同位素分布特征及其古植被意义

对察尔汗盐湖ISL1A钻孔沉积物样品进行了有机分子地球化学分析, 检测出了丰富的类脂物, 包括正构烷烃、一元正脂肪酸、一元正脂肪醇等, 本文主要讨论正构烷烃类脂物的分布特征。正构烷烃的分布型式表明其来源于低等菌藻类生物和陆生高等植物, 正构烷烃的高碳数部分均有显著的奇偶优势, 高碳数正构烷烃全部以C31 为主峰碳。正构烷烃分布特征表明在110.1~50.1 ka B.P.期间, 察尔汗盐湖地区为草原植被景观。对C27、C29、C31 长链正构烷烃进行了单体碳同位素测定, 利用二元模式估算了C3 和 C4 植物的相对输入贡献, 结果表明, 以C3 植物为主。

Chemical and compound-specific carbon isotopic characteristics of n-alkanes in the Qarhan Salt Lake sediments and their paleovegetation significance

Molecular biomarkers, including n-alkanes, n-alcohols and n-alkanoic acids, were identified in the core sediments taken from the Qarhan Salt Lake by GC/MS analysis. The distribution of n-alkanes was mainly discussed in this paper. The n-alkanes exhibited strong odd-over-even carbon number predominance and the main peak at C31, suggesting that they were derived from terrestrial higher plants. The distribution of n-alkanes indicated that the grass vegetation was dominated in the Qarhan Salt Lake area during 110.1 ka B.P. to 50.1 ka B.P. In addition, the compound-specific carbon isotopic composition was determined for C27, C29 and C31 n-alkanes in the core. Relative contribution of C3 and C4 plants was estimated by using a binary model, indicating that C3 plants are a dominantinput.