Theme 3 will explore the co-evolution of minerals and proteins through geologic time.  We propose to carry out data-driven abductive studies of mineral evolution that document the changes in Earth’s mineral diversity and distribution through deep-time, focusing on mineral interactions with the biosphere. Mineralogical data (e.g., mineral composition, solubility, and age) will be incorporated into geochemical models to constrain the concentration of metals over geologic time and metal bioavailability during Archean and Proterozoic eons.

We will then use the availability of redox-active transition metals to date specific positions in the protein evolution tree constructed in Theme 2. Employing large meta-omics and geochemical datasets of modern environments, we will test if metal concentrations are reliable markers for the occurrence of protein cofactors, and thus the validity of using metal bioavailability to constrain a protein evolution timeline. Finally, we will explore if the co-evolution of minerals and proteins resulted in specific suites of minerals that may actually be fossil “geobiosignatures” of life. We hypothesize that mineral diversification on Earth was a consequence, direct or indirect, of the biosphere.

Using a “Large Number of Rare Events” statistical approach, we will compare Earth’s mineral distribution with that of Mars, the Moon, and meteorites. This work will allow us to distinguish key differences in mineral diversity and distribution on terrestrial planets and moons, and reveal if minerals require life to proliferate.