不同类型沉积物中脂肪酸的分布、演化和生烃意义

对近代海洋沉积物、泥炭、福山凹陷第三系泥岩、茂名盆地第三系油页岩和辽河盆地东部凹陷第三系沉积岩剖面等样品中脂肪酸类型和分布特征进行了分析与研究。结果表明以低等浮游动植物为主的沉积中，二元肪酸丰度相对比一元酸占优势。随深程度增加，沥青中脂肪酸高碳数相对减少，低碳数相对增高，偶碳估势逐渐消失。在辽河盆地东部凹陷埋深２２６６ｍ的泥岩中发现脂肪酸仍具有偶碳优势，证明沉积有机质中偶碳脂肪酸优势可以保存到生油高峰前的较高演化阶段，对低熟原油烷烃的生成和具奇碳优势有重要意义。

The Distribution and Evolution of Fatty Acids in Various Sediments and Its Significance

The type and distribution of fatty acids in the recent marine sediment, peat, Tertiary mud stone ofthe Fusha depression, oil shale of the Maomin basin and a cerise of Tertiary core samples from the east-ern depression of the Liaohe basin were analysed and investigated. As a result, the predominant fattyacids in the bitumen of sediments with planktons as the main input were found to be monocarboxylicacids,whereas more abundanta,cu dicarboxylic acids were found in the sediment with terrigenous highplants as the main input. The relative abundance of long-chain and short-chain acids in fatty acids ofsamples was found to be reducing and increasing, respectively, with increasing evolution of samples. E-limination in the preference of even to odd carbon acids was observed with increasing the evolution ofs am p les,too. The fact that fatty acids in the rock collected at 2266m from the eastern depression of theLiaohe basin are still showing preference of evencardo n to odd cardon demonstrated that the fatty acidswith preference of even to odd cardon can be reserved in sedimentary rocks before they reach to the peakstage of generating hydrocarbons and that the fatty acids in sedimentary rocks can play an important rolefor generating alkanes with preference of odd carhon to even caron in immature oils.