Primordial organic molecules may have evolved in seafloor hydrothermal systems by mineral catalysis. Most organic compounds decompose in >300 °C vent fluid; however, we show that smectite-type clays can protect and promote development of diverse organic compounds that may be precursors to biomolecules. Smectite provides a safe haven for the synthesis of organic molecules, essentially like a “primordial womb.”
Our experiments simulated seafloor hydrothermal conditions (300 °C, 100 MPa) and reacted common clays (montmorillonite, saponite, illite) with dilute methanol as a source of C. Montmorillonite reacts under these conditions to illite, while the other clays do not change. We observed increased organic synthesis over time with montmorillonite during mineralogical reaction. Approaching equilibrium, smectite contracts and organic molecules are expelled. Organic compounds unstable in hot fluid where the smectite reacts may survive in cooler waters outside the vent.