成都理工大学尹坤教授和南京大学陆现彩教授，近日研究揭示了毛钙硅石是熔融温度最高的地幔矿物。相关论文发表在2023年12月8日出版的《科学进展》杂志上。

研究人员基于密度泛函理论的第一性原理分子动力学模拟，研究了 MgSiO₃ 和 CaSiO₃ 在地幔稳定场作用下的熔融曲线。毛钙硅石的熔融曲线与前人的研究结果非常吻合，证实了前人对其熔融温度的普遍共识。然而，该团队预测的毛钙硅石的熔化曲线却比几乎所有以前的估计都要高得多。

在核幔交界压力下(约 136 吉帕斯卡)，毛钙硅石的熔融温度约为 7700(150) K，比布氏岩高约 2000 K。毛钙硅石的超耐火性对于重新考虑早期岩浆海洋的凝固和地幔岩石的地球动力学行为等许多深层行星内部模型至关重要。

据悉，了解硅酸盐矿物的高压熔融曲线对于模拟岩石行星的热化学演化至关重要。然而，作为地球下地幔中第三丰富的矿物，毛钙硅石的熔化温度仍然存在争议。

附：英文原文

Title: Davemaoite as the mantle mineral with the highest melting temperature

Author: Kun Yin, Anatoly B. Belonoshko, Yonghui Li, Xiancai Lu

Issue&Volume: 2023-12-08

Abstract: Knowledge of high-pressure melting curves of silicate minerals is critical for modeling the thermal-chemical evolution of rocky planets. However, the melting temperature of davemaoite, the third most abundant mineral in Earth’s lower mantle, is still controversial. Here, we investigate the melting curves of two minerals, MgSiO₃ bridgmanite and CaSiO₃ davemaoite, under their stability field in the mantle by performing first-principles molecular dynamics simulations based on the density functional theory. The melting curve of bridgmanite is in excellent agreement with previous studies, confirming a general consensus on its melting temperature. However, we predict a much higher melting curve of davemaoite than almost all previous estimates. Melting temperature of davemaoite at the pressure of core-mantle boundary (~136 gigapascals) is about 7700(150) K, which is approximately 2000 K higher than that of bridgmanite. The ultrarefractory nature of davemaoite is critical to reconsider many models in the deep planetary interior, for instance, solidification of early magma ocean and geodynamical behavior of mantle rocks.

DOI: adj2660

Source: https://www.science.org/doi/10.1126/sciadv.adj2660