地球核-幔边界超离子转变导致的脱水现象缺失
近日，葡京网投app_澳门葡京游戏-【在线*平台】：地球化学研究所何宇团队报道了地球核-幔边界超离子转变导致的脱水现象缺失。相关论文于2026年1月28日发表在《科学进展》杂志上。
含水矿物的性质与稳定性对揭示深部水循环之谜至关重要。在深部下地幔条件下，水与含水矿物会转变为超离子态。然而，超离子态对其稳定性及脱水行为的影响尚不明确。
通过采用从头算分子动力学与深度学习势函数分子动力学模拟，研究组在δ-AlOOH中发现了一种双超离子态相变，其特征是氢离子和铝离子在氧亚晶格内均呈现高度扩散行为。这些高度扩散的元素为体系提供了额外的熵贡献，使其在140吉帕斯卡和3800开尔文的极端条件下保持稳定。自由能计算表明，在深部下地幔条件下水倾向于"冻结"，因此即使在核幔边界条件下，脱水过程在能量和动力学上也均难以发生。这意味着超离子态水可能在地质时间尺度上持续积聚于深部下地幔，在地幔底部形成长期储水库。
附：英文原文
Title: Absence of dehydration due to superionic transition at Earth’s core-mantle boundary
Author: Yu He, Wei Zhang, Qingyang Hu, Shichuan Sun, Jiaqi Hu, Daohong Liu, Li Zhou, Lidong Dai, Duck Young Kim, Simon A. T. Redfern, Yun Liu, Heping Li, Ho-kwang Mao
Issue&Volume: 2026-01-28
Abstract: The properties and stability of hydrous phases are crucial to unraveling the mysteries of the deep water cycle. Under deep lower mantle conditions, water and hydrous phases transition into a superionic state. However, superionic effect on their stability and dehydration behavior remains unclear. Using ab initio and deep learning potential molecular dynamics simulations, we discovered a doubly superionic transition in δ-AlOOH, characterized by the highly diffusive behavior of both hydrogen and aluminum ions within the oxygen sublattice. These highly diffusive elements contribute external entropy to the system, stabilizing the structure at 140 GPa and 3800 K. Our free-energy calculations reveal that water tends to freeze under deep lower mantle conditions, so dehydration becomes energetically and kinetically unfavorable even under core-mantle boundary (CMB) conditions. This implies that superionic water may accumulate in the deep lower mantle over geologic time, forming a long-term reservoir at the base of the mantle.
DOI: aeb3006
Source: https://www.science.org/doi/10.1126/sciadv.aeb3006
