C-16-C-29 homologous series of monomethylalkanes in the pyrolysis productsof a Holocene microbial mat

Preparative open pyrolysis products of kerogen isolated from a Holocene mic robial mat collected in Abu Dhabi (United Arab Emirates) contain homologous series of monomethylalkanes (MMAs, C-16-C-29) The isomer and carbon number distributions of these branched alkanes closely match those of MMAs in anc ient sediments and oils. It is proposed that monomethylalkanes in oils and in thermally mature ancient sediments derive from non-extractable organic m atter produced by one or more members of the cyanobacterial assemblage, eub acterial primary producers and/or heterotrophic bacteria. (C) 2000 Elsevier Science Ltd. All rights reserved.