Condensate glasses from the Zhamanshin crater. II. Zhamanshinites

Abstract

Condensate glasses of two types were found during the SEM and TEM investigation of zhamanshinite samples within volumetrically dominant melt glass: silica-rich glasses similar to irghizite-type condensates and moderately silicic sodium-rich glasses deposited in voids in zhamanshinites. The latter are characterized by globular morphology, high contents of volatile components, and presence of inclusions a few hundred nanometers in size. The differences of the zhamanshinite-type condensate glasses from irghizitetype condensates are related to their slower cooling and closeness of the pore space system. The results of the investigation of melt glasses of various color groups from the same samples are presented for comparison. The glasses of each group appeared to be homogeneous at the SEM level, but inhomogeneous at the TEM scale.