法国国家科学院和里昂第一大学Bernard Bourdon团队研究了地球冥古宙原地壳的形成和组成。2025年4月2日出版的《自然》杂志发表了这项成果。

尽管地球和其他类地行星一定有早期形成的原地壳，但这种地壳的化学成分很少受到关注。原地壳是从小行星体吸积和熔融形成的广阔岩浆海洋中提取的。实验和时间数据都表明，从这个岩浆海洋上升的硅酸盐熔体是在金属被提取形成地核的平衡状态下或之后形成的。

研究组表明，在这些条件下形成的原地壳具有与当前平均大陆地壳非常相似的不相容（相对于硅酸盐矿物）微量元素特征。这对随后的行星演化具有重大影响。关于板块构造何时以及如何开始的许多地球化学争论隐含地假设，俯冲是产生大陆微量元素特征所必需的。如果该发现已经是冥古宙协议的一个特征，这些论点就会受到严重损害。

附：英文原文

Title: Formation and composition of Earth’s Hadean protocrust

Author: Turner, Simon, Wood, Bernard, Johnson, Tim, ONeill, Craig, Bourdon, Bernard

Issue&Volume: 2025-04-02

Abstract: Although Earth, together with other terrestrial planets, must have had an early-formed protocrust, the chemical composition of this crust has received little attention. The protocrust was extracted from an extensive magma ocean formed by accretion and melting of asteroidal bodies1. Both experimental and chronological data suggest that the silicate melt ascending from this magma ocean formed in equilibrium with, or after, metal was extracted to form Earth’s core. Here we show that a protocrust formed under these conditions would have had incompatible (with respect to silicate minerals) trace-element characteristics remarkably similar to those of the current average continental crust. This has major implications for subsequent planetary evolution. Many geochemical arguments for when and how plate tectonics began implicitly assume that subduction is required to produce the continental trace-element signature. These arguments are severely compromised if this signature was already a feature of the Hadean protocrust.

DOI: 10.1038/s41586-025-08719-3

Source: https://www.nature.com/articles/s41586-025-08719-3