Dynamics of changes in the physical characteristics of a hydrothermally altered geological section according to nonisothermal physicochemical simulation (the Mutnovsky Volcano)

The paper presents the results of numerical simulation of a subaerial volcanic hydrothermal system. The model is based on the factual data on the rock composition and the geological structure of the Mutnovsky Volcano. We develop a new approach to construct the numerical model of a volcanic hydrothermal system. According to this approach, at each step of the calculation, for each point of the spatiotemporal domain, the thermophysical properties are determined; further, these properties are used in the calculation of the equilibrium state of the system. This procedure allows us to take into account the dynamic changes in the T-P conditions in the cross section and the migration of the phase boundaries. As well, using this approach, we can pass from “conditional” time in the description of the evolution of the magmagenic fluid system to the “virtually dimensional time” of the development of the simulated ore-magmatic system, from the onset of melt crystallization in the intrusive chamber up to the termination of the retrograde boiling of the melt. The simulation shows that, depending on the structure of the lower part of the section, contrasting hydrothermal systems can develop in the originally homogeneous medium. The relation between the temperature, and, therefore, phase composition of the fluid and the features of the hydrothermal alteration in volcanic rocks is demonstrated. Among other questions, in the present paper we discuss the changes in the density and magnetic properties of the volcanogenic section.