9706546 Rushmer 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.
