Crystallization Kinetics: Quantitative Analysis and Numerical Simulation of Metamorphic Textures

9902682卡尔森我们试图通过使用高分辨率X射线计算机断层扫描（CT）来研究变斑质结构，以确定变质反应的机制和速率。结晶的机制将提取从X射线CT数据的统计测量的大小和位置的晶体，电子探针分析的组成分区模式，在他们的比较与不同的动力学控制下的结晶的数值模拟的预测。将构建新的数值模型，以比以前更接近自然界中的结晶，这些模型将与CT数据拟合，以约束绝对反应速率。 研究的主要目的是：（1）收集广泛的变质岩结构特征，这些结构特征的地质背景使它们可能揭示温度、压力、流体渗透、变形、加热速率、先驱颗粒尺寸、内部扩散竞争和界面反应速率对结晶动力学的影响;（2）建立结晶的数值模拟模型，以捕捉在这些设置中的每一个中变质反应的本质特征;（3）利用新的数值模拟方法解释构造数据，阐明了变质反应的机理，并量化了决定其速率的关键动力学参数。

9902682CarlsonWe seek to determine the mechanisms and rates of metamorphic reactions by using high-resolution X-ray computed tomography (CT) to study porphyroblastic textures. Mechanisms of crystallization will be extracted from the X-ray CT data by means of statistical measures of the sizes and locations of crystals, electron-microprobe analysis of compositional zoning patterns in them, and comparison with the predictions of numerical simulations of crystallization under diverse kinetic controls. New numerical models will be constructed to approximate crystallization in nature more closely than was possible before, and these models will be fit to the CT data to constrain absolute reaction rates. The principal objectives of the research are: (1) to assemble a broad inventory of textural features in metamorphic rocks whose geologic settings makes them likely to reveal information about the effects on crystallization kinetics of temperature, pressure, fluid infiltration, deformation, heating rates, precursor grain size, internal diffusional competition, and interfacial-reaction rates; (2) to create models for numerical simulation of crystallization that capture the essential character of metamorphic reaction in each of these settings; and (3) to use those new methods of numerical simulation to interpret textural data, clarifying mechanisms of metamorphic reactions and quantifying the critical kinetic parameters that determine their rates.