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

地球和行星科学的一个基本问题是行星是如何形成的，以及它们是如何随着时间的推移而演变的。地球化学和数值模型，以及类似的行星模型表明，地球是由复杂的加工物质吸积而成，然后在形成后迅速进化。早期的事件，如地核分离、地幔分化和地壳形成，似乎是在地球增生后不久发生的。此外，在地球形成的最后阶段，物质的不断增加改变了地幔的组成。在过去的几年里，短寿命同位素计时器的发展使得对地球增生后不久发生的事件进行年代学研究成为可能。通过地幔对流和与板块构造相关的地壳再循环的混合，减弱了原始地幔非均质性的强度。然而，太古宙早期形成的同位素变化的最新文献表明，原始化学储层持续存在了100 - 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.