A thermodynamic model for silicate melt in CaO–MgO–Al2O3–SiO2 to 50 kbar and 1800 °C
A thermodynamic model for silicate melt in CaO–MgO–Al2O3–SiO2 to 50 kbar and 1800 °C
复制标题
CaO-MgO-Al2O3-SiO2 中硅酸盐熔体在 50 kbar 和 1800 °C 下的热力学模型
DOI：
10.1111/j.1525-1314.2012.00982.x
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发表时间：
2012
影响因子：
3.4
通讯作者：
Roger Powell
中科院分区：
文献类型：
--
作者：
E. Green;T. Holland;Roger Powell
对CaO-MgO-Al_2 O_3-SiO_2（CMAS）镁铁质熔体的完全热力学模型进行了标定，用于计算0-50 kbar压力范围内的熔体平衡。 它旨在作为迈向大系统熔体模型的初步步骤，适用于探索各种天然岩石成分中的熔融、熔体损失和结晶过程。校准进行注意到模型的行为在其组成的子系统，作为一个严格的测试模型的结构和参数化。该模型与最新的Holland & Powell热力学数据集一致，因此可以与为该数据集编写的许多固相活性-组成模型一起用于计算相关系。模型计算成功地再现了CMAS尖晶石二辉橄榄岩和石榴子石二辉橄榄岩组合，以及蓝闪石和蓝晶石轴承组合，在中高压实验熔融反应。热力学敏感的功能，如热分割也恢复。然而，一些变化的模型结构将需要之前，该模型可以描述的所有范围内的镁铁和超镁铁熔体组合物已知的实验在低压下。
A fully thermodynamic model for mafic melt in CaO–MgO–Al2O3–SiO2 (CMAS) has been calibrated, for calculation of melting equilibria in the pressure range 0–50 kbar. It is intended as a preliminary step towards a large‐system melt model, suitable for exploring melting, melt loss and crystallization processes in a wide range of natural rock compositions. Calibration was performed with attention to the model's behaviour in its compositional subsystems, as a rigorous test of model structure and parameterization. The model is consistent with the latest Holland & Powell thermodynamic data set, and can therefore be used to calculate phase relations in conjunction with the many solid‐phase activity–composition models written for the data set. Model calculations successfully reproduce experimental melting reactions in CMAS spinel lherzolite and garnet lherzolite assemblages, as well as sapphirine‐ and kyanite‐bearing assemblages, at moderate to high pressure. Thermodynamically sensitive features, such as thermal divides are also recovered. However, some changes to the model structure will be required before the model can describe the full range of mafic and ultramafic melt compositions known from experiment at low pressures.