【摘要】 为了探讨季风边缘区气候变化特征,对内蒙古磴口一个深15m的钻孔沉积物中的正构烷烃进行了分析.结果显示,正构烷烃总体呈现出以高碳数为主的分布特征,表明其主要来源于陆生高等植物,多数样品以nC27、nC29为主峰,奇碳优势明显,局部样品以nC25为主峰,显示了流域植被类型为木本植物和少量水生植物.但在钻孔上部短链正构烷烃相对丰度较高,主要以nC18为主峰,无明显的奇偶优势,反映了低等藻类生物增加.正构烷烃的分布特征在沉积钻孔中表现出的多阶段变化,与岩性、有机碳同位素等变化相吻合,反映出研究区寒暖交替的气候条件.更多还原

【Abstract】 To characterize the palaeoclimatic variations in monsoon margin zone,n-alkane analyses are done on samples collected from one borehole of 15 min depth in Dengkou,Inner Mongolia.The results indicate that most samples are dominated by high carbon,primarily nC27 and nC29,presenting a significant odd-carbon advantage and terrestrial origin.Several samples with a main peak of nC25 show the organic origin of partial aquatic plants.However,in the upper part of the borehole,short chain nalkanes are relatively abundant,mainly with nC18 as the main peak and without obvious odd-even predominance,reflecting the increased algal biomass.It is found that alternately cold and warm climatic conditions dominated the study area by various distributions of n-alkanes in sediments,in line with lithology and organic carbon isotope variations in this study.更多还原