Water distribution in dynamically recrystallized quartz grains: cathodoluminescence and micro-infrared spectroscopic mapping

Abstract

Abstract The distribution of water in dynamically recrystallized quartz aggregates in granitic mylonites was investigated by cathodoluminescence (CL) observations and micro-infrared (IR) spectroscopic mapping. It is clear from CL observations and micro-IR spectroscopic mappings that the CL intensity and contrast depend on the density of defects (e.g. the content of molecular H 2 O and absorbed OH species). Dynamic recrystallization, as a recovery process of intracrystalline strain, decreases the densities of excess carriers originated from defects. The decrease in the densities of excess carriers decreases the CL intensity and contrast within each grain. To investigate the effect of water weakening in the rheological properties of the crust, CL spectroscopy and micro-IR spectroscopic mapping are essential in the determination of concentration and distribution of water in natural high-strain zones.