C16–C29 homologous series of monomethylalkanes in the pyrolysis products of a Holocene microbial mat

Preparative open pyrolysis products of kerogen isolated from a Holocene microbial mat collected in Abu Dhabi (United Arab Emirates) contain homologous series of monomethylalkanes (MMAs, C16–C29). The isomer and carbon number distributions of these branched alkanes closely match those of MMAs in ancient sediments and oils. It is proposed that monomethylalkanes in oils and in thermally mature ancient sediments derive from non-extractable organic matter produced by one or more members of the cyanobacterial assemblage, eubacterial primary producers and/or heterotrophic bacteria.