Wilson Alfred J, Davies Christopher J, Walker Andrew M, Alfè Dario
School of Earth and Environment, University of Leeds, Leeds, UK.
Department of Earth Sciences, University of Oxford, Oxford, UK.
Nat Commun. 2025 Sep 4;16(1):7685. doi: 10.1038/s41467-025-62841-4.
The composition of Earth's core is a fundamental property of the Earth's deep interior, defining its present structure and long term thermal and magnetic evolution. However, the composition of the core is not well understood, with several combinations of light elements being able to satisfy the traditional constraints from cosmochemistry, core formation and seismology. The classic view of inner core formation does not include the necessity for liquids to be supercooled to below their melting point before freezing. Attempts to calculate the magnitude of this supercooling have found that several binary core compositions are incompatible with inner core nucleation. Here we show, through molecular dynamics simulations, that nucleation from an FeC composition is compatible with a range of geophysical constraints. Whilst not a complete description of core chemistry, our results demonstrate that inner core nucleation places a strong constraint on the composition of Earth's core that may allow discrimination between previously identified potential compositions.
地核的成分是地球深部内部的一个基本属性，它决定了地球目前的结构以及长期的热演化和磁演化。然而，地核的成分尚未得到很好的理解，几种轻元素的组合能够满足来自宇宙化学、地核形成和地震学的传统约束条件。关于内核形成的经典观点并不包括液体在凝固前必须过冷到熔点以下的必要性。计算这种过冷度大小的尝试发现，几种二元地核成分与内核成核不兼容。在这里，我们通过分子动力学模拟表明，FeC成分的成核与一系列地球物理约束条件是兼容的。虽然这不是对地核化学的完整描述，但我们的结果表明，内核成核对地核的成分施加了强大的约束，这可能有助于区分先前确定的潜在成分。
