论文标题
从Mo-Ru同位素系统推断的地球异质积聚
Heterogeneous accretion of Earth inferred from Mo-Ru isotope systematics
论文作者
论文摘要
陨石的Mo和Ru同位素组成和散装硅酸盐（BSE）掌握了有关地球建筑材料来源的重要线索。先前的研究表明，非碳质（NC）和碳质（CC）陨石基团共同定义了Mo-Ru'Cosmic'相关性，并且BSE在扩展此相关性方面图。这些观察结果作为证据，表明地球的最后10-15％的材料源自具有enstatite软骨样同位素组合物的同质内盘储层。在这里，使用新的MO和RU同位素数据用于以前未经投票的陨石组，我们表明Mo-Ru相关性仅对NC Meteorites存在，并且BSE和CC陨石都脱离了这种Mo-Ru相关性。这些观察结果表明，地球积聚的最后阶段是异质的，由NC和CC材料的混合物组成。 MO-RU同位素系统最好由已故贴面的NC遗产与结合了月球形成巨型撞击器的CC遗产或两个组件混合的NC-CC组成。 CC体参与地球晚期增生组合与核心甲分化的化学模型一致，这认为在地球形成的尽头添加了更多氧化和挥发性丰富的材料。因此，这项研究解决了基于对陨石的Mo-Ru系统学的先前解释和地球异质积聚的化学证据，可以解决均相积聚模型之间的不一致之处。
The Mo and Ru isotopic compositions of meteorites and the bulk silicate Earth (BSE) hold important clues about the provenance of Earth's building material. Prior studies have argued that non-carbonaceous (NC) and carbonaceous (CC) meteorite groups together define a Mo-Ru 'cosmic' correlation, and that the BSE plots on the extension of this correlation. These observations were taken as evidence that the final 10-15% of Earth's accreted material derived from a homogeneous inner disk reservoir with an enstatite chondrite-like isotopic composition. Here, using new Mo and Ru isotopic data for previously uninvestigated meteorite groups, we show that the Mo-Ru correlation only exists for NC meteorites, and that both the BSE and CC meteorites fall off this Mo-Ru correlation. These observations indicate that the final stages of Earth's accretion were heterogeneous and consisted of a mixture of NC and CC materials. The Mo-Ru isotope systematics are best accounted for by either an NC heritage of the late veneer combined with a CC heritage of the Moon-forming giant impactor, or by mixed NC-CC compositions for both components. The involvement of CC bodies in the late-stage accretionary assemblage of Earth is consistent with chemical models for core-mantle differentiation, which argue for the addition of more oxidized and volatile-rich material toward the end of Earth's formation. As such, this study resolves the inconsistencies between homogeneous accretion models based on prior interpretations of the Mo-Ru systematics of meteorites and the chemical evidence for heterogeneous accretion of Earth.
