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

9814524伦敦在代表花岗岩系统的高硅熔体中，在中等至低PT制度下，石英和碱性长石的生长动力学对自由能的总体最小化以及结晶过程中化学平衡的实现是重要的。 这项工作的中心目标是开发一个全面的模型耦合成核和生长动力学的结晶相从过冷的含水熔体的haplogranite组合物（系统Ab-Or-Qtz-H2O）。该项目具有两个重要部分：一组实验需要提供的基本数据的成核和晶体生长在过冷花岗岩系统，和一个数值模型，通过该模型将实验现象的热力学，动力学和运输性能的晶体熔体系统。从实验中寻求的关键测量将包括：（1）熔体中结构弛豫的时间，（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）熔体中边界层的产生和分散。 这些数据将以速率定律的形式进行总结，例如我们使用Wolfram Research软件MATHEMATICA的解决方案模块为Ab-Qtz-H2O系统开发的速率定律。该计划的最终目标是开发动力学模型，可以准确地预测过冷花岗岩熔体的结晶反应。

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.