Researchers from the Institut de chimie des milieux et matériaux de Poitiers (IC2MP, Université de Poitiers/CNRS) led by Abderrazak El Albani in collaboration with an international team have developed a new scientific approach that could reveal traces of biological activity in ancient rocks. The study, which has been published in Nature Communications might also help in the exploration of very discreet traces of life on Mars.
The results from this work suggest that microbial biofilms trapped K+ from seawater and released it into the pore-waters during respiration, resulting in a process called illitisation. The K-rich illite developed exclusively in fossilized structures thus provides a new biosignature for metasediments derived from K-feldspar-depleted rocks that were abundant crustal components on ancient Earth, say the researchers.
Read the research paper: J. Aubineau, A. El Abani, A. Bekker, A. Somogyi, O. M. Bankole, R. Macchiarelli, A. Meunier, A. Riboulleau, J-Y Reynaud & K. O. Konhauser. Microbially induced potassium enrichment in Paleoproterozoic shales and implications for reverse weathering on early Earth. Nature Communications 10.1038/s41467-019-10620-3