Melt Segregation and Strain Localization in Response to Shear Deformation of Partially Molten Rocks, a Transition from Porous to Channelized Flow

智力优势：这项研究开发的物理机制和地球物理意义的熔体偏析和应变局部化，发生在实验室变形的部分熔融岩石使用最近开发的扭转变形能力，使样品在相对较大的地质重要的应变剪切的基本理解。 它侧重于系统的调查，部分熔融系统的目的是了解熔体的偏析，组织熔体丰富的乐队，和应变的分区的流变效应。 实验将在高温和高压下用扭转装置进行，以确定样品在恒定速率和恒定应力实验中的流动行为。 将使用SEM和EBSD对运行产品进行详细的微观结构分析，以限制与熔体偏析相关的应变局部化机制。 主要目标是为理论分析提供约束条件，这对于理解潜在的物理机制至关重要，并制定标度律，以便将实验室条件下的实验结果外推到地幔时空尺度上发生的过程。 它还将开发新的方法来研究熔体偏析扭转实验。研究结果将纳入本科课程工作。

Intellectual Merit: This research develops a fundamental understanding of the physical mechanisms and geophysical implications of melt segregation and strain localization that occur during laboratory deformation of partially molten rocks using recently developed torsional deformation capabilities that enable samples to be sheared at relatively large geologically important strains. It focuses on a systematic investigation of partially molten systems with the goal of understanding the rheological effects of the segregation of melt, the organization of melt-rich bands, and the partitioning of strain. Experiments will be carried out at high temperatures and pressures with a torsion apparatus to determine the flow behavior of samples in constant rate and constant stress experiments. Detailed microstructural analyses of run products will be carried out using SEM and EBSD to place constraints on the mechanisms responsible for the localization of strain associated with melt segregation. Primary goal is to furnish constraints for theoretical analyses that are critical for understanding the underlying physical mechanisms and develop scaling laws for extrapolation of experimental results from laboratory conditions to processes occurring at mantle temporal and spatial scales.Broader Impacts: This work will engage undergraduates in research and support a graduate student and postdoctoral researcher at the University of Minnesota. It will also develop new methodologies for studying melt segregation by torsion experiments. Results of the research will be incorporated into undergraduate course work.