PROTOS · The role of silica in the dawn of life on our planet

All information humankind has of the ancient past of our planet comes from analyzing the geological record encoded in rocks. There is, however, no rock record of the first 600 million years of Earth’s history. Unlocking the secrets of this earliest period –the Hadean– is a fundamental task for science, as it is key to understanding how the planet became habitable, when the first forms of metabolism and self-replication developed, and life appeared. The lack of a geological record has led scientists to use computational modeling to make inferences about the conditions in Early Earth’s environments. Less common are laboratory experiments specifically targeted to simulating Hadean conditions. Based on ubiquitous carbonaceous chert deposits in the oldest rock record, it is widely accepted that many early Archean aquatic settings were reducing and rich in silica and some basic carbon-based molecules. We reason that such aquatic conditions were already established during the early Hadean, and inevitably led to the existence of a large-scale factory of simple and complex organic compounds, many of them relevant to prebiotic chemistry and to the route to biomimetic hybrid microstructures able to self-organize and catalyze prebiotic reactions relevant to the origin of life. Our project is aimed at understanding the crucial role of silica in directing the geochemical and protobiological processes, creating habitats for early life, and preserving early biomass on Earth’s surface during the first billion years of its history. PROTOS will use an array of laboratory experiments (the Hadean Simulator) to systematically study ab-initio reactions of water and gases with the earliest rock types in order to determine compositions of aquatic habitats and subsequent silica precipitation mechanisms, organic synthesis processes on silica/iron surfaces, and the preservation of the first remnants of life. PROTOS will change our view of the infancy of the planet.