A modern perspective on ancient life: Microbial mats in sandy marine settings from the Archean era to today

Abstract

Most valuable paleontological studies on the ancient life in the Archean era are on fossils of bacterial cells preserved in chert, or on the famous stromatolites we find in the oldest carbonate or silica rocks. The past decade, a new window into Earth's most antique worlds opened: Modern sandy coastal areas and the biofilms and microbial mats therein! The interaction of the modern microbial mats with the physical sediment dynamics creates sedimentary structures of mm to m sizes. Those 'microbially induced sedimentary structures-MISS' are found in the fossil record as well. Both modern and fossil examples look alike, but much different to stromatolites. We distinguish 17 main types of those MISS, related to their modes of formations. Our studies showed that ancient microbial mats developed in tidal, lagoonal, and shelf sandstones during the Phanerozoic, and Proterozoic ages, and even colonized already sandy marine deposits billions of years ago-during the Archean time. The ancient MISS suggest the existence of cyanobacteria potentially before 3 billion years ago. © 2011 Springer Science+Business Media B.V.