Melt segregation from highly crystallized magmas under simple shear

我们考察了单纯剪切作用下岩浆的微观结构。微观结构的演变受两个因素的影响：(1)颗粒取向与最大主轴之间的几何关系；(2)颗粒-流体和颗粒-颗粒相互作用的大小，这些相互作用改变了颗粒的旋转行为。第一个因素导致粒子取向和局部粒子分数的耦合。第二个因素控制粒子的旋转行为。通过这两种因素的共同作用，颗粒因剪切诱发应变而重新排列，微观结构和体粘度均达到稳态状态。在此条件下，微观结构由两个具有不同颗粒分数和颗粒取向的畴组成。随着颗粒分数的增加和颗粒间相互作用的增加，团簇的形成具有较强的颗粒间力，导致了液体的偏析。这些发现对火成岩流动相关微观结构的运动学研究具有重要意义。

We examined the microstructure of magma under simple shear. The evolution of the microstructure is governed by two factors : (1) geometric relationships between the particle orientation and the maximum principal axis and (2) magnitude of particle-fluid and particle-particle interactions, which modifies the rotation behavior of particles. The first factor results in the coupling of the particle orientation and the local fraction of particles. The second factor controls the rotation behavior of particles. Through the combined effect of the two factors, particles are rearranged because of shear-induced strain, and both the microstructure and the bulk viscosity reach a steady-state condition. Under this condition, the microstructure is composed of two domains having different particle fractions and particle orientations. Increase in particle fraction and particle-particle interaction develops the cluster with strong inter-particle force, which results in the segregation of liquid. These findings have important implications for the kinematics of the flow-related microstructure recorded in igneous rocks.