Figure 1

Sample MP26 (a) and optical microscope image of a thin slab of MP26, the location of frothy inclusions is indicated by the arrows (b). Backscattered electron images of a sub-spherical coesite-bearing inclusion, characterized by coesite microcrystals and relict quartz crystals (c,d). Backscattered electron images of an elongated coesite bearing inclusion (from Glass et al.¹⁰), characterized by a relict quartz rim and froth vesicles that are increasingly larger outward from the inclusion (e,f). Backscattered electron images of two lechatelierite inclusions (g,h).