A new model for silicification of cyanobacteria in Proterozoic tidal flats

Microbial fossils preserved by early diagenetic chert provide a window into the Proterozoic biosphere, but seawater chemistry, microbial processes, and interactions between microbes environment that contributed to this preservation are not well constrained. Here, we use fossilization experiments explore processes preserve marine cyanobacterial biofilms precipitation of amorphous silica in medium is analogous seawater. These demonstrate exceptional silicification benthic cyanobacteria oldest diagnostic requires among extracellular polymeric substances (EPS), photosynthetically induced pH changes, magnesium cations (Mg2+), >70 ppm silica.