德国哥廷根格奥尔格·奥古斯特大学Nils Messling团队近日发现洋岛玄武岩Ru、W同位素系统揭示岩心渗漏。该研究于2025年5月21日发表在《自然》杂志上。

与地幔柱相关的熔岩的同位素组成先前已根据地核-地幔相互作用进行了解释，这表明地幔柱可能将地核物质输送到地球表面。然而，地核在地幔中的确切指纹仍未得到证实。贵金属，如钌（Ru），在金属核心高度集中，但在硅酸盐地幔中极度贫化。最近在古代岩石中发现的与质量无关的Ru同位素变化（ε¹⁰⁰Ru）表明，在地球生长的后期，增生物质的Ru同位素组成发生了变化，这表明地核和地幔一定有不同的Ru同位素成分。这说明了钌同位素作为地核-地幔相互作用新示踪剂的潜力。 

研究组报道了海岛玄武岩的钌同位素异常。夏威夷玄武岩的ε¹⁰⁰Ru高于周围地幔。结合非放射性钨（W）同位素比值，这是对其地幔源的核心贡献的诊断。夏威夷玄武岩的Ru和W同位素组合系统最好用简单的岩芯夹带来解释，但在岩芯-地幔边界添加岩芯衍生的氧化物矿物是可能的。

附：英文原文

Title: Ru and W isotope systematics in ocean island basalts reveals core leakage

Author: Messling, Nils, Willbold, Matthias, Kallas, Leander, Elliott, Tim, Fitton, J. Godfrey, Mller, Thomas, Geist, Dennis

Issue&Volume: 2025-05-21

Abstract: The isotopic composition of lavas associated with mantle plumes has previously been interpreted in the light of core–mantle interaction, suggesting that mantle plumes may transport core material to Earth’s surface1,2,3,4,5. However, a definitive fingerprint of Earth’s core in the mantle remains unconfirmed. Precious metals, such as ruthenium (Ru), are highly concentrated in the metallic core but extremely depleted in the silicate mantle. Recently discovered mass-independent Ru isotope variations (ε100Ru) in ancient rocks show that the Ru isotope composition of accreted material changed during later stages of Earth’s growth6, indicating that the core and mantle must have different Ru isotope compositions. This illustrates the potential of Ru isotopes as a new tracer for core–mantle interaction. Here we report Ru isotope anomalies for ocean island basalts. Basalts from Hawaii have higher ε100Ru than the ambient mantle. Combined with unradiogenic tungsten (W) isotope ratios, this is diagnostic of a core contribution to their mantle sources. The combined Ru and W isotope systematics of Hawaiian basalts are best explained by simple core entrainment but addition of core-derived oxide minerals at the core–mantle boundary is a possibility.

DOI: 10.1038/s41586-025-09003-0

Source: https://www.nature.com/articles/s41586-025-09003-0