Chemical heterogeneities in the early Earth and planetary analogues: their formation, preservation and destruction

地球和行星科学中的一个基本问题是行星如何形成以及它们如何随着时间的推移而演变。地球化学和数值模型，以及行星类似物表明，地球从复杂的加工材料中增生，然后在形成后迅速进化。早期事件，如核分离，地幔分异和地壳形成似乎发生在地球吸积后不久。此外，在形成的最后阶段，地幔的成分因物质的不断增加而改变。在过去的几年里，短寿命同位素计时器的发展使得对地球吸积后不久发生的事件进行年代学研究成为可能。与板块构造有关的地幔对流和地壳再循环的混合作用减弱了原始地幔的不均匀性。然而，最近在太古代岩石中早期形成的同位素变化的文件要求原始化学水库的持续性超过10亿年。

A fundamental question in Earth and planetary sciences is how the planets formed and how they evolved through time. Geochemical and numerical models, as well as planetary analogs suggest that Earth accreted from complex processed materials and then evolved rapidly after its formation. Early events such as core segregation, mantle differentiation and crust formation seem to have occurred shortly after the Earth’s accretion. Furthermore, the composition of the Earth’s mantle was modified by the continued accretion of materials during the final stages of formation. In the past few years, the development of short-lived isotopic chronometers has allowed chronological studies of the events that followed shortly the Earth’s accretion. Mixing through mantle convection and crustal recycling associated with plate tectonics has attenuated the magnitude of primordial mantle heterogeneities. However, recent documentation of early-formed isotope variations in Archean rocks requires the persistence of primordial chemical reservoirs for > 1 billion years.