Magmatic immiscibility provides phosphate for prebiotic chemistry

Phosphorus is essential for extant and nascent life. However, phosphate's low terrestrial abundance and the poor aqueous solubility of phosphorus-bearing minerals pose major hurdles for prebiotic chemistry. Here, we show that silicate-phosphate immiscibility in volcanic melts could have provided a widely available mechanism for the local enrichment of phosphate. Starting with a phosphorus-enriched Archean melt, we observe that rapid cooling results in the formation of immiscible glassy droplets with up to 21 weight % phosphorus pentoxide, which can be delivered to the surface by volcanic processes. In aqueous leaching, we detect millimolar phosphate concentrations, which enable the synthesis of phosphorylating agents such as polyphosphates and imidazole phosphate with up to 34% yield. These results demonstrate how volcanic processes can enrich phosphate to fuel prebiotic chemistry.