Quantification of element transport processes in metamorphic rocks - simulating garnet porphyroblast growth in a three dimensional composition-space-time system.

变质岩中元素迁移机制和迁移率的定量化是最具挑战性的，因为它可以精确预测和定量成矿和成岩过程。石榴子石斑晶和它们的成分生长环带显示了一个很好的记录，其寄主岩石内的元素运输，因为它们准确地反映了生长过程中的营养需求和动力学约束的元素可用性之间的相互作用。提取这一有价值的信息是阻碍的事实，即石榴石的生长和组成上的不同的限速因素的相互作用没有完全理解。在这个项目中，我们将使用一个集成的多方法的方法，石榴石生长的热力学，成核，扩散和微量元素建模的结果进行比较，从三维断层扫描和原位微量元素分析的自然观测。这种组合将适用于不同构造变质环境的样品，这些样品很好地保留了各种典型和特征的石榴石生长模式，并从已发表的数据中获得了大量信息。我们的方法将产生关键的信息反应路径，元素传输机制和速率，以及它们的反射在石榴石的生长模式。这些信息有助于解释石榴石的地球动力学和地球化学过程的特征成分。

Quantification of element transport mechanisms and -rates in metamorphic rocks is most challenging as it allows precise prediction and quantification of ore- and rock-forming processes. Garnet porphyroblasts and their compositional growth zonations display an excellent record of element transport within their host rocks, as they precisely reflect the interplay between thermodynamically controlled nutrient demand and kinetically constrained element availability during growth. Extraction of this valuable information is hindered by the fact that the interplay of different rate-limiting factors on garnet growth and -composition are not fully understood. In this project we will use an intergrated multi-method approach where the results of thermodynamic-, nucleation-, diffusion-, and trace element-modeling of garnet growth are compared with natural observations derived from 3D-tomographic and in situ trace-element analyses. This combination will be applied to samples from different tectonometamorphic settings that excellently preserve various typical and characteristic garnet growth patterns with plenty of information readily available from published data. Our approach will yield crucial information about reaction paths, element transport-mechanisms and -rates as well as their reflections in growth patterns in garnet. Such information facilitates interpretations of characteristic compositional features in garnet in terms of geodynamic and geochemical processes.