Geochemical Constraints on the Origin of the Moon and Preservation of Ancient Terrestrial Heterogeneities
Geochemical Constraints on the Origin of the Moon and Preservation of Ancient Terrestrial Heterogeneities
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DOI：
10.1007/s11214-020-00729-z
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发表时间：
2020-09
影响因子：
10.3
通讯作者：
S. Lock;K. Bermingham;R. Parai;M. Boyet
中科院分区：
文献类型：
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作者：
S. Lock;K. Bermingham;R. Parai;M. Boyet
月球形成的巨大撞击标志着地球吸积主要阶段的结束，并为我们星球的后续演变奠定了基础。40年来，巨大撞击理论一直是公认的月球起源模型，但撞击的参数和导致月球形成的机制仍然存在激烈的争论。在这里，我们审查的主要地球化学观测，约束的时间和参数的影响，月球形成的机制，和地球的同期演化。我们将讨论如何对月球，陆地和陨石样品的化学和同位素研究与物理模型，以及它们如何可以用来区分月球起源模型。特别是，我们认为，在碰撞过程中的混合效率是巨大的影响模型的一个关键测试。要解释地球和月球之间的同位素相似性，需要高度的撞击内混合，但与此同时，撞击并没有使整个地球地幔均匀化，因为撞击前不均匀性的同位素特征被保留下来。我们总结了该领域的前景，并强调了推进我们对月球起源的理解所需的测量和建模方面的关键进展。
The Moon forming giant impact marks the end of the main stage of Earth’s accretion and sets the stage for the subsequent evolution of our planet. The giant impact theory has been the accepted model of lunar origin for 40 years, but the parameters of the impact and the mechanisms that led to the formation of the Moon are still hotly debated. Here we review the principal geochemical observations that constrain the timing and parameters of the impact, the mechanisms of lunar formation, and the contemporaneous evolution of Earth. We discuss how chemical and isotopic studies on lunar, terrestrial and meteorite samples relate to physical models and how they can be used to differentiate between lunar origin models. In particular, we argue that the efficiency of mixing during the collision is a key test of giant impact models. A high degree of intra-impact mixing is required to explain the isotopic similarity between the Earth and Moon but, at the same time, the impact did not homogenize the whole terrestrial mantle, as isotopic signatures of pre-impact heterogeneity are preserved. We summarize the outlook for the field and highlight the key advances in both measurements and modeling needed to advance our understanding of lunar origin.