SIGNIFICANCE OF LIQUID IMMISCIBILITY IN THE GENESIS OF OBSIDIAN AND PERLITE OF AZERBAIDZHAN

Abstract

We investigated liparite domes that include Pliocene obsidians and perlites in the Kel'badzhar region of Azerbaidzhan. Elements of perlitic texture are identifiable in pumice and obsidian, as a result of which they too may undergo hydration (which is the basis for a technique of dating obsidian artifacts). But in general, dense (obsidian) textures of glass arise when the separation of water from the melt preceded their extrusion and glass generation (in deep chambers during the ascent of the melts to the surface), or the case of rapid quenching of melts that prevented dehydration during generation and the associated 'natural blow-up' of glass. The separation of water from silicic melts also prevents them from taking up other volatile components, particularly fluorine and boron.