沉积有机质中藿烯的成因研究——碳稳定同位素证据

Origin Study of Geohopenes from Different Depositional Environments Stable Carbon Isotopic Evidences

结合传统有机地球化学和新兴生物标志物单烃碳稳定同位素技术，首次较系统地研究了来自不同沉积环境，代表不同干酪根类型样品中的藿烯类化合物，获得如下认识：泥炭样品中的里白烯是某种细菌或蓝细菌的合成物，里白烯的同位素组成相对于来自Ｃ３５藿类先质的其它藿类明显亏损１３Ｃ，这种Ｃ３０的藿类先质分子对泥炭中藿类的贡献较小，在８．５５％～３．１７％之间；Δ１３（１８）新藿烯是Δ１７（２１）藿烯的热力学转化产物。

Compound specific isotopic study in combination with conventional organic geochemical investigation of hopenes from 'thermally immature' samples representing various kerogen types,depositional environments in a try to further the understanding of the bioorigin of geohopenes and to quantitate the relative contribution of C30 precursor co occuring with C35 precursor shows:①C30Δ22(29) hopene in the peat samples can be differentiated from other hopanoids presumed to be the transformation products of C35 precusor molecule on the basis of conspicuous difference between their stable carbon isptopic fingerprints.The contribution of C30 precursor(8.55%～3.17%) in the studied peats is relatively small when compared with C35 precusor(91.45%～96.83%);②The double bond migration mechanism from Δ17(21) to Δ13(18) is resubstantiated.