Evolution of the crustal phosphorus reservoir

Walton, Craig R.; Hao, Jihua; Huang, Fang; Jenner, Frances E.; Williams, Helen; Zerkle, Aubrey L.; Lipp, Alex; Hazen, Robert M.; Peters, Shanan E. and Shorttle, Oliver (2023). Evolution of the crustal phosphorus reservoir. Science Advances, 9(18)

DOI: https://doi.org/10.1126/sciadv.ade6923

Abstract

The release of phosphorus (P) from crustal rocks during weathering plays a key role in determining the size of Earth's biosphere, yet the concentration of P in crustal rocks over time remains controversial. Here, we combine spatial, temporal, and chemical measurements of preserved rocks to reconstruct the lithological and chemical evolution of Earth's continental crust. We identify a threefold increase in average crustal P concentrations across the Neoproterozoic-Phanerozoic boundary (600 to 400 million years), showing that preferential biomass burial on shelves acted to progressively concentrate P within continental crust. Rapid compositional change was made possible by massive removal of ancient P-poor rock and deposition of young P-rich sediment during an episode of enhanced global erosion. Subsequent weathering of newly P-rich crust led to increased riverine P fluxes to the ocean. Our results suggest that global erosion coupled to sedimentary P-enrichment forged a markedly nutrient-rich crust at the dawn of the Phanerozoic.