Types of petrochemical trends of subsolvus fractions of basic melts during their sulfurization and reduction

Abstract

Trap rocks conjugated with iron, copper, and nickel ore occurrences and deposits contain petrochemical rock groups with unusual (for tholeiites) ratios of components. Such compositions cannot be produced by the cotectic crystallization of melts. They can conditionally be defined as ore magmas. Analysis of the thermodynamic characteristics of such magmas of sulfide and iron ore deposits in the Siberian Craton revealed [1] the following fact: sulfurization, ferritization, and reduction of basic melts lead to the realization of unpredictable compositional variations of liquid fractions; the conditions of their separation during the emplacement of magmas can be responsible for the formation of different types of ore and silicate liquids. The theory of the sulfurization and ferritization of basic melts in the course of gaseous phase barbotage across basic liquids [2, 3] forecasts and the experience of the study of real objects demonstrates complex petrogenetic realizations of processes of the initial magma decomposition in heterophase ore-magmatic systems [4‐7]. Study of the inequilibrium subsolvus fractions, which are recorded during the vitrification of decaying real initial basic magmas, suggests the possible petrochemical trends that characterize the processes of composition variation during the impact of the gaseous phase upon basic liquid. In this paper, we attempted to demonstrate the statistically significant characteristics of liquid fractions revealed during the decay of contaminated tholeiitic liquids.