The role of silica in a lifeless planet

Ubiquitous as life is today, and as it was during most of the Earth’s geological history, our planet was once devoid of life. There are two main problems in investigating the early and barren stage of our planet. First, there are no rock remains from the first half a billion years of Earth’s history (the Hadean eon). Second, the impact of life on the geochemistry of the planet has been and is so important that we cannot use actualism to reveal the chemistry that prevailed during the planet’s early age. Following the latest information provided by Hadean zircons, water condensed on the Earth’s surface shortly after the solidification of its first ultramaphic crust. The thermally driven interaction between water and ultramafic minerals (serpentinization) created an alkaline hydrosphere, rich in silica and a reducing atmosphere, which triggered the formation of complex organic compounds. I propose that this global geochemical scenario also triggered the formation of silica-based mineral self-organized structures that played an important role in the transition from inorganic to organic chemistry and ultimately to the origin of life itself. I will discuss in the talk i) the fundamentals of mineral self-assembly, ii) its geochemical plausibility and iii) its role in the problem of detecting primitive life and in catalyzing the formation of biochemically relevant prebiotic compounds