Phosphorus sorption by terrestrial basalt and granite and implications for the martian crust

High phosphorus concentrations in the range of 0.5 wt% in rocks and soil have been measured on the martian surface, terrestrial P concentrations are far less uniform and generally lower. Reactions of terrestrial basalt and granite powders with phosphate solution result in an enrichment of phosphorus in both, with basalt having a far better reactivity than granite. The implications of these results for P on Mars are discussed.