Originally posted by galathaea
Oh come on, now! Cyanobacteria don't produce protective fibers like lignin and are consumed long before they are buried deep enough for the oil generating processes!
aww you made me have to go look this crap up shame on you...not that I want to get in a P'ing match with you, I'd have to spend too much time refreshing my memory, and that cuts into my beer time.

Oil inclusions fluoresce under excitation by ultraviolet light and were found in ~1400 million-yr-old sandstone in the Roper Superbasin, Australia. The molecular composition of the oil determined by careful gas chromatography–mass spectrometry revealed a complex composition that has remained protected from the outside environment since trapping. Biomarkers show that the oil was derived from the remains of bacteria, in particular cyanobacteria. Colonies of these aquatic and photosynthesizing microbes also form stromatolites, which are some of the oldest fossils in the world, and are responsible for having generated an oxygen-rich atmosphere. Future work on even older samples could lead to a richer and more robust record of early microbial life.