Abstract Eighteen successful diffusion couple experiments in 8-component SiO2–TiO2–Al2O3–FeO–MgO–CaO–Na2O–K2O basaltic melts were conducted at 1260 °C and 0.5 GPa and at 1500 °C and 1.0 GPa. These experiments are combined with previous data at 1350 °C and 1.0 GPa (Guo and Zhang, 2018) to study the temperature dependence of multicomponent diffusion in basaltic melts. Effective binary diffusion coefficients of components with monotonic diffusion profiles were extracted and show a strong dependence on their counter-diffusing component even though the average (or interface) compositions are the same. The diffusion matrix at 1260 °C was obtained by simultaneously fitting diffusion profiles of all diffusion couple experiments as well as appropriate data from the literature. All features of concentration profiles in both diffusion couples and mineral dissolution are well reproduced by this new diffusion matrix. At 1500 °C, only diffusion couple experiments are used to obtain the diffusion matrix. Eigenvectors of the diffusion matrix are used to discuss the diffusion (exchange) mechanism, and eigenvalues characterize the diffusion rate. Diffusion mechanisms at both 1260 and 1500 °C are inferred from eigenvectors of diffusion matrices and compared with those at 1350 °C reported in Guo and Zhang (2018). There is indication that diffusion eigenvectors in basaltic melts do not depend much on temperature, but complexity is present for some eigenvectors. The two slowest eigenvectors involve the exchange of SiO2 and/or Al2O3 with nonalkalis. The third slowest eigenvector is due to the exchange of divalent oxides with other oxides. The fastest eigenvector is due to the exchange of Na2O with other oxide components. Some eigenvalues differ from each other by Ti oxide mineralization.

中文翻译：

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玄武岩熔体中的多组分扩散：温度依赖性

摘要 在 8 组分 SiO2-TiO2-Al2O3-FeO-MgO-CaO-Na2O-K2O 玄武岩熔体中进行了 18 次成功的扩散偶实验，实验分别在 1260 °C 和 0.5 GPa 以及 1500 °C 和 1.0 GPa 下进行。这些实验与之前在 1350 °C 和 1.0 GPa 下的数据相结合（Guo 和 Zhang，2018 年），以研究玄武岩熔体中多组分扩散的温度依赖性。提取了具有单调扩散剖面的组分的有效二元扩散系数，即使平均（或界面）成分相同，也表现出对其反扩散组分的强烈依赖性。1260 °C 的扩散矩阵是通过同时拟合所有扩散偶实验的扩散曲线以及来自文献的适当数据获得的。这种新的扩散矩阵很好地再现了扩散偶和矿物溶解中浓度分布的所有特征。在 1500 °C 时，仅使用扩散偶实验来获得扩散矩阵。扩散矩阵的特征向量用于讨论扩散（交换）机制，特征值表征扩散速率。1260 和 1500 °C 的扩散机制是从扩散矩阵的特征向量推断出来的，并与郭和张（2018）报道的 1350 °C 的那些进行比较。有迹象表明玄武岩熔体中的扩散特征向量不太依赖于温度，但某些特征向量存在复杂性。两个最慢的特征向量涉及 SiO2 和/或 Al2O3 与非碱的交换。第三个最慢的特征向量是由于二价氧化物与其他氧化物的交换。最快的特征向量是由于 Na2O 与其他氧化物成分的交换。一些特征值因钛氧化物矿化而彼此不同。