The H₂O solubility in peralkaline haplogranitic melts has been experimentally determined as a function of pressure (27–200 MPa) and temperature (1123–1523 K). The compositions were based on Ab₃₈Or₃₄Qz₂₈ (AOQ) with 4 and 8 wt% Na₂O in excess. H₂O solubility experiments were performed in an internally heated pressure vessel and quenched to glasses for analysis. For quantification of H₂O contents in the glasses using FTIR analysis, the linear molar absorption coefficients as a function of Na₂O excess with respect to AOQ composition were determined, as well as the glass densities as a function of H₂O concentration. The H₂O solubility increases with increasing pressure, decreasing temperature, and with increasing peralkalinity. A linear dependence between Na₂O excess (wt%) and H₂O solubility (wt%) was found. It has been previously shown that on a molar basis the different alkalis contribute similarly to the H₂O solubility increase so that H₂O solubility increases linearly with excess alkali (difference between mole fractions of alkalis and that of alumina). Thus, the dependence of H₂O solubility on pressure, temperature and excess alkali obtained from the new data of this study allow a simple prediction of H₂O solubility for peralkaline rhyolitic melts based on the excess alkali content. This new empirical model was tested with H₂O solubility data from literature for peralkaline haplogranitic and natural peralkaline rhyolitic melt compositions, yielding good agreement (< 10% deviation) between predicted and observed H₂O solubility, which is an improvement compared to previous models. The model can be applied to natural peralkaline rhyolitic melts that occur, e.g. on Pantelleria, Gran Canaria, or the East African Rift.

H ₂ O 在过碱性单花岗岩熔体中的溶解度已通过实验确定为压力（27-200 MPa）和温度（1123-1523 K）的函数。该组合物基于Ab ₃₈或₃₄ Qz _{28 (AOQ)，其中Na 2} O过量为4和8 wt% 。H ₂ O 溶解度实验在内部加热的压力容器中进行并淬火到玻璃中进行分析。为了使用 FTIR 分析对玻璃中的 H ₂ O 含量进行量化，确定了线性摩尔吸光系数作为 Na ₂ O 过量相对于 AOQ 组成的函数，以及玻璃密度作为 H _2的函数O 浓度。H ₂ O 溶解度随着压力增加、温度降低和过碱度增加而增加。发现Na ₂ O过量（wt%）和H ₂ O溶解度（wt%）之间存在线性相关性。先前已经表明，在摩尔基础上，不同的碱对 H ₂ O 溶解度增加的贡献相似，因此 H ₂ O 溶解度随着碱的过量而线性增加（碱金属的摩尔分数与氧化铝的摩尔分数之间的差异）。因此，从本研究的新数据中获得的 H ₂ O 溶解度对压力、温度和过量碱的依赖性允许对 H _{2进行简单预测}基于过量碱含量的过碱性流纹岩熔体的 O 溶解度。这种新的经验模型使用来自文献中的过碱性单花岗岩和天然过碱性流纹岩熔体组合物的 H _{2 O 溶解度数据进行了测试，在预测和观察到的 H 2} O 溶解度之间产生了良好的一致性（< 10% 偏差），与以前的模型相比，这是一个改进. 该模型可以应用于发生在例如潘泰莱里亚、大加那利岛或东非裂谷的天然过碱性流纹岩熔体。