Non-chondritic iron isotope ratios in planetary mantles as a result of core formation

摘要: Information about the materials and conditions involved in planetary formation differentiation early Solar System is recorded iron isotope ratios. Samples from Earth, Moon, Mars asteroid Vesta reveal significant variations ratios, but sources of these remain uncertain. Here we present experiments that demonstrate under core expected for Vesta, isotopes fractionate between metal silicate due to presence nickel, enrich bodies’ mantles isotopically light iron. However, effect nickel diminishes at higher temperatures: Earth’s formation, infer little fractionation isotopes. From our experimental results existing conceptual models magma ocean crystallization mantle partial melting, find nickel-induced can explain variability found samples without invoking nebular or accretionary processes. We suggest near-chondritic ratios basalts as well most primitive lunar basalts, were achieved by melting mantles, whereas heavy terrestrial floor are result Earth mantle. Planetary variation composition across bodies. Experiments this be explained varying degrees during depending on temperature.