Subgrain Boundaries as Sites of Melt Generation and Pathways for Melt Flow: Implications for Rheology From Combined Chemical and Quantitative Orientation Analysis

Abstract

Partial melting influences important Earth processes, including the generation of crustal-forming melts and the softening of the lower crust or mantle, impacting the structure of the continents and tectonic plates. Both melt generation/extraction and rheologic weakening are known to be influenced by several factors, but two important parameters are the nature and evolution of the melt network in a partially molten rock. For example, the permeability of melt varies not just with melt fraction but also with grain size (von Bar-