Collaborative Research: Geochemical Signatures of Melt Segregation in Static vs. Dynamic Environments

[706047 .布雷尔利]关注地壳演化的地球科学家目前正在争论熔体分离的速率、熔体运输途径的性质以及构造环境的作用。岩浆化学是研究的重点，因为这些过程决定了提取的熔体与源岩平衡的程度。因此，确定熔体偏析机制如何影响熔体化学将大大提高我们对在无水花岗岩地体中观察到的成分范围和地壳演化的理解。在这个项目中，我们将通过实验测试这样一个假设，即熔体分离的物理过程留下了一个独特的化学特征，可以在熔净熔体中观察和量化。在静态和变形条件下进行的实验将使我们能够确定以下情况下的熔体成分：1)在静态环境中沿着熔体填充的裂缝发生迁移；2)在动态环境中沿着剪切带集中迁移。这些实验结果将为构造环境、深熔过程中活跃的偏析速率和岩浆组成三者之间的联系提供重要线索。

9706047 Brearley Geoscientists concerned with crustal evolution are currently debating the rates of melt segregation, the nature of the pathways for melt transport, and the role of tectonic environment. In particular, focus has been placed on magma chemistry because these processes determine the extent to which the extracted melts are in equilibrium with their source rocks. Thus, determining how the mechanics of melt segregation influences melt chemistry would greatly enhance our understanding of the range in compositions observed in anatectic granitic terranes and of the evolution of the crust in general. In this project, we will experimentally test the hypothesis that the physical process of melt segregation leaves a distinct chemical signature that can be observed and quantified in anatectic melts. Experiments performed under both static and deformation conditions will allow us to determine melt compositions when 1) migration occurs along melt-filled cracks in quiescent environments and 2) when migration is focused along shear zones in dynamic environments. Together, these experimental results will provide an important link between tectonic environment, segregation rates active during anatexis and the magma compositions themselves.