Thermodynamic model for partial melting of peridotite by system energy minimization
Thermodynamic model for partial melting of peridotite by system energy minimization
复制标题
系统能量最小化橄榄岩部分熔融热力学模型
DOI：
10.1029/2012gc004143
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
H.
中科院分区：
文献类型：
--
作者：
Ueki;K.;Iwamori;H.
我们提出了一种新的简单算法，该算法计算熔体存在系统的能量最小化，并结合了新校准的硅酸盐熔体热力学参数。该算法搜索导致系统具有总吉布斯自由能（G）的全局最小值的平衡相集合、分数和组成。它使用恒定的体积组成约束来计算相对于熔体和固体端元组分的最小溶解或固化量的G变化。此外，我们还制定了一套固熔体端元组分和溶解-沉淀化学计量，使熔融存在系统的建模成为可能。熔体热力学性质基于理想混合模型使用Δ Cp和ΔV（分别为相应熔体和固体端元组分之间的摩尔比热和体积差）进行校准，基于先前研究期间建立的固体性质。我们还描述了应用能量最小化算法和热力学熔体参数熔融尖晶石二辉橄榄岩在1 GPa，在SiO2-Al 2 O3-FeO-Fe 3 O 4-MgO-CaO系统，包括橄榄石，单斜辉石，斜方辉石，尖晶石。我们的计算结果与实验确定的熔融相关系，温度和相分数的关系，包括固相线温度，表明直接校准的热力学熔体参数的压力和温度对应的熔化条件是一个有用的方法。这里提出的能量最小化算法和热力学配置将允许在各种地球动力学环境中模拟地幔熔融。
We present a new straightforward algorithm that calculates the energy minimization of a melt‐present system and incorporates newly calibrated silicate melt thermodynamic parameters. This algorithm searches for equilibrium phase assemblages, fractions, and compositions that lead to the system having a global minimum of total Gibbs free energy (G). It calculates changes inGwith respect to minimal amounts of dissolution or solidification of melt and solid end‐member components using a constant bulk composition constraint. In addition, we have formulated a set of solid‐melt end‐member components and dissolution‐precipitation stoichiometry that enables the modeling of a melt‐present system. Melt thermodynamic properties are calibrated based on an ideal mixing model using ΔCpand ΔV(the differences in molar specific heat and volume between the corresponding melt and solid end‐member components, respectively), based on solid properties established during previous studies. We also describe the application of the energy minimization algorithm and thermodynamic melt parameters to melting of spinel lherzolite at 1 GPa, in a SiO2–Al2O3–FeO–Fe3O4–MgO–CaO system, including olivine, clinopyroxene, orthopyroxene, and spinel. Our calculations agree well with experimentally determined melting phase relations, and temperature and phase fraction relationships, including solidus temperatures, indicating that direct calibration of thermodynamic melt parameters at pressures and temperatures corresponding to melting conditions is a useful approach. The energy minimization algorithm and thermodynamic configuration presented here will allow the modeling of mantle melting in a variety of geodynamic settings.