CHARACTERISTICS OF GLASSES IN PRODUCTS OF EXPERIMENTAL MODELING OF IMPACT MELTS

Abstract

The transformation of substances under extremely high pressures and temperatures is an actual direction both in the field of solid state physics and materials science, and for natural objects. Among the latter, the most interesting are ultrahigh-pressure high-temperature glasses recently found at the Kara giant meteorite crater (Pai-Khoi, Russia), formed from impact melts at pressure about 60 – 80 GPa and the temperature range of 2300 – 2500 °C. These glasses are characterized by unusual structural and phase state features that require deeper study to clarify their physical properties and the possibility of using them as prototypes of innovative materials. Experimental modeling of the impact process in laboratory conditions allows to identify the nature of phase transformations during impactogenesis. Here the modeling of the impact process has been carried out by short-pulse laser radiation (0.5 ms) on the example of clay-containing siltstones and limestones with and carbonaceous components. The impact glasses have been produced from aluminosilicate and quartz components of the host target rocks of the Kara target under pressure conditions ?90 GPa and temperatures ?7000 °C. To study the synthesized products of the impact glasses, high resolution methods have been used – Raman spectroscopy and scanning electron microscopy with microprobe analysis. The provided studies have shown that under the extreme conditions the impact glasses of a specific composition containing a high concentration of Ca and carbon are formed. Thus, the experiments conducted have shown the possibility of obtaining glasses of a wide composition, including carbon-containing glass, which can be used for further studies aiming to develop new materials and technologies of their producing.