Chemical disequilibrium between crystals and melt in samples from Meradalir

This backscatter electron image of a polished section of a sample from the first day of the Meradalir eruption shows plagioclase and olivine crystals in a basaltic melt, which became glassy during rapid cooling.

Some of the crystals are irregularly shaped and rounded, which indicates that they were dissolving in the melt because of chemical disequilibrium between crystals and melt.

A likely explanation for this is that a new batch of hot magma from below picked up the crystals, which subsequently started to dissolve.