Present-day Earth mantle structure set up by crustal pollution of the basal magma ocean.

ABSTRACT: The crystallization of a global magma ocean during early terrestrial planet evolution and the subsequent segregation of a longer-lived "basal magma ocean" (BMO) atop the core set up the evolution of the mantle-atmosphere system. Although seismic evidence for a BMO exists on present-day Mars and the Moon, the Earth's BMO is (near-)completely solidified. Seismically observed "large low-velocity provinces" (LLVPs) are thought to have resulted from the canonical "fractional" style of BMO crystallization. However, we show using thermodynamic modeling that BMO fractional crystallization yields lowermost-mantle densities much higher than those of LLVPs. In turn, pollution of the BMO by progressive addition of recycled basaltic crust and related "reactive crystallization" can reconcile LLVP volume

SUBMITTER: Ballmer MD 

PROVIDER: S-EPMC12273756 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature