The expression “follow the water” is used to recognize inside the universe, life as it exists on Earth. It is shown here that the expression “follow the high subcritical water” can be used to recognize the components of life that formed prior to the emergence of life. It is also shown that this particular water leaves signatures inside rocks that are produced during high subcritical water–rock interactions. These signatures are ferric minerals, which are currently explained by the presence of microorganisms. The consideration of water in the high subcritical domain may lead to postpone the date of the existence of FeII-oxidizing and O2-producing microorganisms, and consequently the date of the appearance of oxygen in the atmosphere. Alkaline water at pH ~9.5 to 14 and in the specific domain of temperature ~300–350 °C, pressure ~10–25 MPa, and density ~700–600 kg/m3, allows us to understand the formation of silica and ferric minerals, and the synformation of components of life in anoxic geological terrains such as the banded iron formations on early Earth and extraterrestrial objects such as Enceladus. The high subcritical water lets appear the continuity between rocks and life, which is conceptualized by the word “geobiotropy”.
Supplemental Material: Apatite nanoparticles in 3.46–2.46 Ga iron formations: Evidence for phosphorus-rich hydrothermal plumes on early Earth
