The Study On Relationship Between The Distribution Of N-alkanes, Pristane And Environment Change In JinChuan Peatland

Great achievement has been made in the study of biomarkers in peatland. Since n alkanesare highly resistant to biochemical degradation in the sedimentary record, the componentsand distributions in biomarkers of peat profile can help distinguish sources of plant input. AsPrevious studies have shown that the composition of such peat deposits record climaticinformation can serve as a useful tool in palaeoclimate reconstructions. So,in this paper,theauthor selected JinChuan as his sampling area, then analyzed the n alkanes and pristanescomprised in the peat deposits. The n alkanes compositions were determined by GC MS(gaschromatography mass spectrometry) after they were extracted by benzene. From the dataidentified by GC MS,conclusions can be made as follows:1. The distribution of n alkanes are not a sequence,some moleculars are not found in thedetermined results,which would have something to do with the method of extraction.2. The n alkanes usually range from 21 to 35 carbons in chain length,with a maximumabundance at C₂₁,C₂₅,C₂₆or C₂₇. And can be divided into four different types without obviousodd over even preference.3. L/H ratio,revealed typical higher plant distributions. And the parameters C₂₃,C₂₁ /C₂₂+in n alkanes suggests a relationship between vegetations and environmentalconditions at the time of their growth. The abundance of pristane is 0.24% ～1%,and thefigure made from these data shows the abundance of Pr in the peat samples is sensitive toclimate change 1972a B.P. ～1546a B.P.(14C dating).