Crystallization experiments on the formation of pegmatitic texture

Abstract

We conducted crystallization experiments in the system Ab–Qtz–H2O at 0.8 GPa. Fine euhedral Ab and Qtz crystals were formed in the runs with non-eutectic bulk compositions cooled below the liquidus temperature. Their texture was similar to equigranular granites. In the case of eutectic composition, graphic intergrowths of Ab–Qtz and coarse euhedral crystals in the cavities were formed, resulting in a large supercooling of the crystal-free melt and solution-precipitation processes via fluid phase, respectively. These textures mimic the zonation and miarolitic pegmatites.