安徽宣城更新世红土正构烷烃分布特征及其古植被意义  

Distribution of n-Alkanes as Indicative of Paleovegetation Change in Pleistocene Red Earth in Xuancheng, Anhui

作　　者：梁斌[1] 谢树成[1] 顾延生[1] 郭建秋[1] 阮小燕[1] 易轶[1] 黄俊华[1] 

机构地区：[1]中国地质大学地球科学学院

出　　处：《地球科学（中国地质大学学报）》2005年第2期129-132,共4页Earth Science-Journal of China University of Geosciences

基　　金：中国地质调查局项目"中国南方红土型第四系的划分与对比"(No.200113900072);湖北省青年杰出人才基金项目

摘　　要：利用气相色谱-质谱联用仪(GC-MS)在安徽宣城更新世红土中检测出了微量的分子化石,包括正构烷烃、一元正 脂肪酸、一元正脂肪醇以及α-正构脂肪酮等.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,其中高 碳数正构烷烃主要以C29为主峰,显示流域中的植被类型以木本植物为主;(C27+C29)/(C31+C33)比值的变化反映出,在以 木本植物占优势的背景下,流域中草本植物的相对比例也发生了多次变化.这一比值在本剖面上表现出多阶段的变化,而 且这种变化与岩性、粒度变化密切相关,反映出这些参数可能还蕴涵着古气候信息.Using GC/MS analysis, a series of molecular fossils, including n-alkanes, n-alkanoic acids, n-alkanols, and n-alkan-2-ones, have been identified from the Pleistocene red earth in Xuancheng, Anhui Province. The n-alkanes are proposed to be of mixed origin, derived from microorganisms and higher plants. The dominance of C29 homologue in the n-alkane distribution in most samples suggests the occurrence of trees in the region studied here. The parameter of (C27+C29)/(C31+C33) n-alkanes, representative of the abundance of grassy plants relative to woody plants, infers a varied grassy density spanning the last 1 Ma. Profiles of this ratio of n-alkanes display a varied trend comparable with the lithology, an indirect inference of paleoclimate which merits further investigation.

关 键 词：分子化石 红土 第四纪 古植被 

分 类 号：Q91[天文地球—古生物学与地层学]