Phosphorus mineral evolution and prebiotic chemistry: from minerals to microbes

Minerals are known to control the availability of non-volatile and bio-essential elements at Earth’s surface, e.g., phosphorus (P). Therefore, the role of minerals in prebiotic chemistry is a focal point of research into the origins of life. However, the mineralogical diversity of earliest Earth is not definitively known. This uncertainty is owed both to progressive change in the Earth system and an imperfect rock record of Earth history with increasing age. Hence, much is unknown about the planetary conditions under which terrestrial life first developed. Here, we review the plausible diversity of P-bearing phases at Earth’s surface during the emergence of life. We consider phases that were delivered by meteorites (exogenous phases), as well as those that developed solely as a result of Earth system processes (endogenous phases). We take into account the known formation conditions of individual phases, as well as the observed temporal distributions of P-bearing minerals found at Earth’s surface today. Our approach allows us to leverage what is known about changes in the Earth system in order to rule out the prebiotic relevance of many P-bearing phases. Meanwhile, we highlight a small number of phases that are of possible prebiotic relevance; specifically schreibersite, merrillite, apatite, olivine, and glass. Prebiotic mineral-chemical scenarios can be formulated for each phase, with distinct requirements for the environmental and tectonic state of early Earth. We can therefore directly relate the probability of mineral-chemical scenarios to the nature of early Earth, bridging the fields of geoscience and prebiotic chemistry.