Kinetics of Metamorhpic Processes in the Contact Aureoles of Basalt Feeder Dikes, Killala Bay, Ireland

基拉拉湾石灰岩中的玄武岩补给岩脉侵位，在小岩脉（1.5米和5.3米）的光圈和50米岩脉的外光圈中产生了含粗硅灰和硅灰石的组合，在其内光圈中具有非常高的温度组合，并沿其接触面吸收了石灰岩。这些光晕的热历史的数值模拟使它们可以用作自然实验，从中可以恢复方解石，硅灰石和石英的粗化动力学参数。利用地层学、矿物组合和成分以及缓冲组合的热化学和反应过程计算，将确定光晕中的压力、温度、流体组成和流体/岩石比，以便建立一个包含多段给料流的数值热历史模型，岩浆结晶和冷却可以校准。测量的晶粒尺寸分布将用于区分奥斯特瓦尔德成熟和正常晶粒生长的粗化机制，平均晶粒尺寸随接触距离的变化将用于获取晶粒生长的材料常数和活化能。这项工作将在未来的研究中“校准”自然实验室对硅灰石动力学和石英位错的粗晶核和退火的分析。

Emplacement of basaltic feeder dikes in limestone at Killala Bay produced grossular- and wollastonite-bearing assemblage in the aureoles of small (1.5 and 5.3m) dikes and in the outer aureole of a 50m dike, which has very high temperature assemblages in its inner aureole and which has assimilated limestone along its contact. Numerical modelling of the thermal histories of these aureoles allows them to be used as natural experiments from which kinetic parameters for the coarsening of calcite, wollastonite and quartz can be recovered. Pressure, temperature, fluid composition and fluid/rock ratio in the aureoles will be determined using stratigraphy, mineral assemblages and compositions, and thermochemical and reaction-progress calculations for buffer assemblages so that a numerical thermal history model involving multiple episodes of feeder flow, magmatic crystallization and cooling can be calibrated. Measured grain-size distributions will be use to distinguish the coarsening mechanisms of Ostwald ripening and normal grain growth, and the variation of the mean grain size with distance from the contact will be used to retrieve material constants and activation energies for grain growth. This work will "calibrate" the natural laboratory for the analysis of the kinetics of wollastonite and grossular nucleation and annealing of quartz dislocations in future studies.