美国卡耐基科学研究所
研究人员证明在对流地幔中，渗流作用可以是一种有效的地核形成机制，并通过地幔和地核之间的部分平衡来改变它们的组成。这种颗粒尺度的金属流动具有较高的流速，以满足核心形成的时间限制。在这一过程中，地核可能富集了轻元素，而地幔中中等亲铁元素的丰度可能升高到目前的值。在应力诱导渗流过程中，地幔中捕获的核形成熔体也可以解释地幔中高度亲铁元素的丰度。
据悉，地核形成机制决定了地幔和地核中亲铁元素和轻元素的丰度。先前的研究表明，大量液态金属通过固体硅酸盐地幔的下沉导致了一个不平衡的地核和下地幔。
附：英文原文
Title: A partially equilibrated initial mantle and core indicated by stress-induced percolative core formation through a bridgmanite matrix
Author: Lin Wang, Yingwei Fei
Issue&Volume: 2023-02-15
Abstract: The Earth’s core formation mechanism determines the siderophile and light elements abundance in the Earth’s mantle and core. Previous studies suggest that the sink of massive liquid metal through a solid silicate mantle resulted in an unequilibrated core and the lower mantle. Here, we show that percolation can be an effective core formation mechanism in a convective mantle and modify the compositions of the lower mantle and the core through partial equilibration between them. This grain-scale metal flow has a high velocity to meet the time constraint of core formation. The Earth’s core could have been enriched with light elements, and the abundance of the moderately siderophile elements in the mantle could have been elevated to the current value during this process. The trapped core-forming melt in the mantle during the stress-induced percolation can also explain the highly siderophile element abundance in the Earth’s mantle.
DOI: ade3010
Source: https://www.science.org/doi/10.1126/sciadv.ade3010