Re-experimentally constrained aluminum, lithium and phosphorus partitioning between zircon and melt: implication for early Earth’s crust evolution and possible habitability

The aluminum (Al), lithium (Li) and phosphorus (P) in zircon, combining their partitioning coefficients between zircon and silicate melt, may show important insights into the evolution of Earth’s crust and habitability over geological timescales, but their partitioning coefficients have not been experimentally studied in detail. In this study, we conducted high-temperature experiments to constrain the partition coefficients of Al (D_Al), Li (D_Li) and P (D_P) between zircon and silicate melt. Our experiments firstly show the amounts of P has the identifiable effects on D_Al and D_Li, but not on itself. The positive and negative correlations of D_Al and D_Li as P content in zircon increasing enables us to constrain the aluminum saturation index (ASI) and Li content of the parental melt of zircon, respectively, by comparing their contents in zircon. The re-evaluated ASI values over time yields two significant increases at 3.6 Ga and 1.0 Ga, whereas, the calculated Li content of Earth’s crust non-linearly decrease with time. Meanwhile, the P content of early Earth’s crust is constrained to 1779 ppm before 3.0 Ga, similar to the present-day crust level of 2052 ppm. These indicate that the global scale tectonic events occurred on the Earth around 3.6 Ga and 1.0 Ga, and that the early Earth could have had a life habitability, and it did not get receded during the terrestrial crust evolution.