Qi, Chao2014-12-242014-12-242014-10https://hdl.handle.net/11299/168286University of Minnesota Ph.D. dissertation. October 2014. Major: Earth Sciences. Advisor: David L. Kohlstedt. 1 computer file (PDF); ix, 113 pages, appendices A-B.The redistribution of melt in partially molten rocks during deformation plays an important role in the evolution and dynamics of Earth's mantle. Previous studies discovered different scales of melt redistribution: melt alignment and melt segregation to form melt-enriched bands , both of which have demonstrated their importance to the deformation of the mantle. In this dissertation, two new forms of stress-driven melt redistribution in deformed partially molten rocks are produced: a formation of pressure shadows around rigid particles and a large-scale, base-state melt segregation. For pressure shadows, observations on the microstructure around the rigid particles revealed the melt distribution and solid flow field, which will provide a constraint on the bulk viscosity of the partially molten rock, if associated with theoretical studies. The presence of base-state melt segregation validated a hypothesis of viscous anisotropy, which provides explanations for melt segregation processes and will cause a significant impact to the dynamic of the mantle. Therefore, the studies of stress-driven melt redistribution in this dissertation are of great significance that will influence the future studies of Earth's mantle.enDeformationOlivinePartial meltingSegregationEarth sciencesStress-driven melt redistribution in partially molten rocks deformed in torsion: from pressure shadows to base-state segregationThesis or Dissertation