Molecular fossils and microfossils of prokaryotes and protists from Proterozoic sediments

Reviews and summarizes the results of recent biomarker studies of well-preserved sediments in the light of current micropaleontological and geochemical perceptions. Several occurrences of Proterozoic hydrocarbons are known, including one from the Early Proterozoic, where there is good reason to believe that the biomarkers represent the remains of microbes living at the time the sediments were deposited. The identities of specific hydrocarbons in these assemblages correlate well with information derived from independent geological and paleontological observations. Furthermore, the biomarker distribution patterns are unusual when compared to Phanerozoic sediments, suggesting that Proterozoic microbial ecosystems were generally different in composition to those from younger sedimentary environments. -from Authors