Comparative characteristics of diaplectic and melt silicate glasses of the Kara astrobleme

Abstract

The objects of study are diaplectic and melt silicate glasses from vein melt impactites of the Kara astrobleme. Microscopic and spectroscopic characteristics of two glasses with fundamentally different formation mechanisms were obtained, which allowed comparing their structural features. We found that silicate diaplectic and melt impact glasses from high-pressure/high-temperature vein bodies of the Kara astrobleme were characterized by similar structural features — a high degree of polymerization, the presence of four-membered and polymembered SiO4 rings, which was characteristic of all glasses were the SiO2 composition. Diaplectic glasses are characterized by the constant presence of three-membered SiO4 rings; melt glasses were characterized by the absence of this feature, which was determined by more extreme conditions for the glass from melt.