Biomarkers diagenesis

The hopane series are the natural product biomarkers elucidated initially as attributable to bacteria.The 17a(H),2ip(H)-hopanes ranging from C27 to C35 (no C28) were encountered in numerous ancient sediments and petroleums, and diagenesis and maturation of the microbial precursors (e.g. bacteriohopanepolyol and diploptene, Fig. 4) were elucidated. The diagenesis of diploptene in contemporary sediments proceeds by double bond migration from via to... 

Madureira L. A. S., Conte M. H., and Eghnton G. (1995) The early diagenesis of hpid biomarker compounds in North Atlantic sediments. Paleoceangraphy 10, 627—642. 

However, some carotenoids retain a taxonomi-cally diagnostic structure during diagenesis and belong to the most important biomarkers for paleoenvironmental reconstructions as discussed below. 

The scheme inFigure 4.12 is an example of extensive and variable biomarker reactions after sedimentation. It illustrates the fate of sterols particularly during diagenesis. Although the scheme looks complex, it shows oidy a few selected stmctures out of more than 300 biogenic steroids and geochemical conversion... 

Hedges, J.I. and Prahl, F.G., 1993. Early diagenesis Consequences for applications of molecular biomarkers. In Engel, M.H. and Macko, S.A. (eds), Organic geochemistry. Principles and applications. Plenum Press, NY, pp. 237-253. 

Ll M., Larter S. R., Taylor P., Jones D. M., Bowler B. and Bjoroy M. (1995) Biomarkers or not biomarker A new hypothesis for the origin of pristane involving derivation from methyltrimethyltridecylchromans (MTTCs) formed during diagenesis from chlorophyll and alkylphenols. Org. Geochem. 23(2), 159-167. 

The molecular composition of an oil is a fingerprint of its source, alteration, and thermal history, and this is also true of oil in fluid inclusions. Early work demonstrated that oil inclusions contained hydrocarbons [108,109], and by 1988, biomarkers were being detected in inclusions by MS and used to constrain the physiochemical aspects of mineral diagenesis [110,111]. Several studies up to 1998 examined the molecular composition of oil inclusions [33,34,45-48,58,59,62,75,81,85,108-117], and many more have been published subsequently. Space does not permit an exhaustive review of all the post-1998 papers. Some highlights from key early papers are presented in the sections below, together with more recent work that particularly demonstrates the breadth of use of MS for analysis. 

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