A Kinetic Model for Crystallization in the Hydrous Haplogranite System (Ab-Or-Qtz-H2O)

9814524伦敦在代表中到低PT区花岗岩体系的高硅熔体中，石英和碱性长石的生长动力学对自由能的整体最小化非常重要，从而在结晶过程中达到化学平衡。这项工作的中心目标是发展一个全面的模型，从过冷的水合单花岗岩熔体(系统AB-或-QTZ-H2O)结晶相成核和生长动力学。该项目包括两个基本部分：一组提供过冷花岗岩系统中成核和晶体生长的基本数据所需的实验，以及一个将实验现象与晶体-熔体系统的热力学、动力学和输运性质联系起来的数值模型。从实验中寻求的关键测量将包括：(1)熔体中结构松弛的时间，(2)成核延迟，(3)晶体尺寸分布的变化率，(4)矿物模式和成分，(5)扩散控制生长的开始，以及(6)熔体中边界层的形成和分散。这些数据将以速率定律的形式汇总，例如我们使用Wolfram研究软件数学软件的解决方案模块为AB-QTZ-H2O系统开发的那些。该计划的最终目标是开发能够准确预测过冷花岗岩熔体中结晶反应的动力学模型。

9814524LondonIn the high-silica melts that represent granitic systems in moderate- to low-PT regimes, growth kinetics of quartz and alkali feldspars are important to the overall minimization of free energy and hence to attainment of chemical equilibrium during crystallization. The central goal of this work is to develop a comprehensive model for the coupled nucleation and growth kinetics of crystalline phases from undercooled hydrous melts of haplogranite composition (system Ab-Or-Qtz-H2O). The project possesses two essential parts: a set of experiments needed to provide the basic data on nucleation and crystal growth in undercooled granitic systems, and a numerical model by which to relate the experimental phenomena to the thermodynamic, kinetic, and transport properties of the crystal-melt system. Key measurements sought from experiments will include: (1) time of structural relaxation in melt, (2) nucleation delay, (3) rate of change of crystal size distribution, (4) mineral modes and compositions, (5) onset of diffusion-controlled growth, and (6) the creation and dispersion of boundary layers in melt. These data will be summarized in the form of rate laws, such as those we have developed for the system Ab-Qtz-H2O using the solution modules of Wolfram Research Software MATHEMATICA. The final goal of the program is to develop kinetic models that can accurately predict the crystallization response in undercooled granitic melts.