Biomarkers or not biomarkers? A new hypothesis for the origin of pristane involving derivation from methyltrimethyltridecylchromans (MTTCs) formed during diagenesis from chlorophyll and alkylphenols

Pristane (2,6,10,14-tetramethylpentadecane), frequently the most abundant biomarker hydrocarbon in crude oils and rock extracts, was thought originally to be derived directly from phytol or, later, from thermal degradation of tocopherols. We present new evidence supporting the hypothesis that pristane, under certain conditions, may result from the catagenic decomposition of methyltrimethyltridecylchromans (MTTCs) derived during diagenesis from condensation reactions between chlorophyll and alkylphenols. We show that phytol can condense, under mild conditions, with phenolic systems (in free or polymeric form) to produce free or bound structures that generate pristenes on flash pyrolysis. We suggest straightforward tests of this hypothesis.