Geological melts / геологические расплавы

Magmas are mixtures of melt, crystals and dissolved gasses with or without crystalline material (Mysen and Richet 2019). They play an important role in igneous processes particularly those influenced by their viscosity, density, and other physical properties. Much of the research to date has used quenched melts (or glasses) as proxies for studying the melt portion of magmas. Studies of glasses and melts at elevated temperatures or in-situ have been carried out since the late 1970s (cf., Waseda and Egami 1979; Exarhos et al. 1988) but remain difficult experiments to perform due to technical difficulties dealing with high temperatures and molten liquids. Problems can arise from, for example, thermal broadening of spectroscopic peaks (often reflecting important dynamics in the liquid state), black body radiation, and motional averaging, as well as challenges of thermal gradients, volatilization, accurate P/T measurement, etc. Another complication is the complex chemical compositions of natural melts and glasses which can make it difficult to analyze and interpret data. Therefore, the glasses studied are usually simple synthetic, rather than natural compositions. The assumption is that the structure of the glass resembles that of the melt at the glass transition temperature, the temperature at which there is a transition from liquid-like to solid-like properties and behavior. One of the key issues is the quality and information content of data obtainable on glasses vs. liquids. <...>