<p>The low <sup>182</sup>W/<sup>184</sup>W and high <sup>3</sup>He/<sup>4</sup>He in some ocean island basalts compared to the bulk mantle values may derive from the Earth’s core through long-term core-mantle interactions. It has been proposed that the grain boundary diffusion of siderophile elements is an efficient mechanism for core-mantle interaction and may effectively modify the W isotopic compositions of the plume-source mantle. In this study, we perform large-scale molecular dynamics simulations driven by machine learning potentials of ab initio quality to investigate the diffusion of W along ferropericlase grain boundaries and in (Mg,Fe)O liquid. Here we show that the diffusion of W is sluggish under core-mantle boundary conditions, and thus is unlikely to have observable impacts on the W isotopic compositions of terrestrial igneous rocks.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Grain boundary diffusion cannot explain the W isotope heterogeneities of the deep mantle

  • Yihang Peng,
  • Takashi Yoshino,
  • Jie Deng

摘要

The low 182W/184W and high 3He/4He in some ocean island basalts compared to the bulk mantle values may derive from the Earth’s core through long-term core-mantle interactions. It has been proposed that the grain boundary diffusion of siderophile elements is an efficient mechanism for core-mantle interaction and may effectively modify the W isotopic compositions of the plume-source mantle. In this study, we perform large-scale molecular dynamics simulations driven by machine learning potentials of ab initio quality to investigate the diffusion of W along ferropericlase grain boundaries and in (Mg,Fe)O liquid. Here we show that the diffusion of W is sluggish under core-mantle boundary conditions, and thus is unlikely to have observable impacts on the W isotopic compositions of terrestrial igneous rocks.