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

Key words: 
• fatty acid /
• peat /
• mudstone /
• oil shale /
• immature oil

Abstract: 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.