New experimental data on the effect of anorthite (An) on liquidus phase equilibria in the system Qz–Ab–Or are presented. The data were obtained for 5 wt% An added to variable Qz/Ab/Or compositions at 300 MPa and under H2O-saturated conditions. Crystal–liquid equilibria were determined for 13 synthetic glass compositions made from gels in experiments performed between 660 and 750 °C in cold-seal pressure vessels. Forward and reversal experiments were systematically conducted on each composition to demonstrate equilibrium. A total of 51 charges was examined. Three crystalline phases, quartz, alkali feldspar and plagioclase appear on the H2O-saturated liquidus surface. The determined minimum liquidus 5 wt% An “piercing” point (39% Qz, 33% Ab, 28% Or) is shifted away from the Ab apex toward the Qz–Or sideline when compared with the An-free 300 MPa H2O-saturated minimum. This shift is of the same type as that observed at 100 MPa in the same system and at 200 MPa in a rhyolitic system. The new experimental results are used to test both empirical and thermodynamic models for silicic magmas. Empirical models reproduce reasonably well the new experimental data, although more sophisticated calculations schemes appear to be required to improve their accuracy. The new experimental results in the haplogranodiorite system are not well reproduced with the model of Holland and Powell (2001), mainly because plagioclase stability appears greatly enhanced in the model. Rhyolite-MELTS satisfactorily reproduces the Qz-, Pl- and Af-liquid phase equilibria, but model H2O solubilities are significantly lower and crystallization temperatures higher than in experiments.

中文翻译：

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钙长石对花岗岩相关系的影响：实验数据和模型

提供了关于钙长石 (An) 对 Qz–Ab–Or 系统中液相平衡影响的新实验数据。数据是在 300 MPa 和 H 2 O 饱和条件下添加到可变 Qz/Ab/Or 组合物中的 5 wt% An 获得的。在 660 至 750 °C 的冷密封压力容器中进行的实验中，确定了由凝胶制成的 13 种合成玻璃组合物的晶液平衡。对每种组合物系统地进行正向和反向实验以证明平衡。共审查了 51 项指控。三个结晶相，石英、碱长石和斜长石出现在 H2O 饱和液相线表面。确定的最小液相线 5 wt% 一个“穿刺”点（39% Qz，33% Ab，与不含 An 的 300 MPa H2O 饱和最小值相比，28% Or) 从 Ab 顶点移向 Qz-Or 侧线。这种位移与在同一系统中在 100 MPa 和在流纹岩系统中在 200 MPa 下观察到的类型相同。新的实验结果用于测试硅质岩浆的经验模型和热力学模型。经验模型相当好地再现了新的实验数据，尽管似乎需要更复杂的计算方案来提高其准确性。Holland 和 Powell (2001) 的模型不能很好地再现单长闪长岩系统中的新实验结果，主要是因为该模型中斜长石稳定性似乎大大增强。流纹岩-熔体令人满意地再现了 Qz-、Pl- 和 Af-液相平衡，