The precipitation of alkaline-earth carbonates in silica-rich alkaline solutions yields nanocrystalline aggregates that develop non-crystallographic morphologies. These purely inorganic hierarchical materials, discovered by the IP of this project, form under geochemically plausible conditions and closely resemble typical biologically induced mineral textures and shapes, thus the name ‘biomorphs’. The existence of silica biomorphs has questioned the use morphology as an unambiguous criterion for detection of primitive life remnants. Beyond applications, the study of silica biomorphs has revealed a totally new morphogenetic mechanism capable of creating crystalline materials with positive or negative constant curvature and biomineral-like textures which lead to the design of new pathways towards concerted morphogenesis and bottom-up self-assembly created by a self-triggered chemical coupling mechanism. The potential interest of these fascinating structures in Earth Sciences has never been explored mostly because of their complexity and multidisciplinary nature. PROMETHEUS proposes an in depth investigation of the nature of mineral structures such as silica biomorphs and chemical gardens, and the role of mineral self-organization in extreme alkaline geological environments. The results will impact current understanding of the early geological and biological history of Earth by pushing forward the unexplored field of inorganic biomimetic pattern formation. PROMETHEUS will provide this discipline with much needed theoretical and experimental foundations for its quantitative application to Earth Sciences. The ambitious research program in PROMETHEUS will require the development of high-end methods and instruments for the non-intrusive in-situ characterization of geochemically important variables, including pH mapping with microscopic resolution, time resolved imaging of concentration gradients, microscopic fluid dynamics, and characterization of ultraslow growth rates.