Hydrogeochemistry of Thermal Sources, Mutnovsky Volcano, South Kamchatka (russia)

In this paper the investigation results of thermal springs of the Mutnovsky Volcano (Kamchatka, Russia) are provided. Mud pots in the Donnoe Field of this volcano have a unique solution composition. High concentrations of a wide spectrum of chemical elements such as Al, Ti, V, Cr, Ni, Co, REE and PGE were discovered there. To explain the mechanisms of solution formation it was made an attempt to describe the fluid evolution and the resulting mixing waters by physical and mathematical modeling. A model illustrates fluid migration from magma chamber to the surface. It is shown that formation of brines corresponding to mud pots composition is possible under the secondary boiling border. THE SUBJECT OF STUDY The Mutnovsky Volcano is one the largest and the most active South Kamchatka volcanoes. It is 2323 m high. Two merged craters are located to the northwest and west of the summit (Fig. 1). The volcano holds multiple cones of neighboring explosions (Selyangin, 1993). Figure 1. Overview of the Mutnovsky volcano. Foto by N.I. Seliverstov from helicopter It has passed in the stage of fumarolic and hydrothermal activities characterized by extremely high energy: 1800-1900 MW in the quite long period of non-active times between 1961 and 2000. Some authors suggest this period as “passive explosion” (Melekescev et al., 1987; Polyak, 1966). Three fumarole fields are located in the eastern crater (1) Verkhnee field with vent temperatures of more than 300°C; (2) Donnoe field consisting of two relatively separate vents with temperatures up to 150°C; (3) Aktive funnel, where powerful gas jets have temperatures up to 570°C. The compositions of gases and hydrothermal solutions of this volcano have been studied sporadically since 1961 (Vakin et al., 1966; Taran et al., 1992; Zelenskii, 2003; Bortnikova et al., 2007 and others). The high seismicity and constant “seismic vibration” of the Earth’s crust provoke changes in the position and activity of fumaroles and hot springs at the Donnoe field (Fig. 2). Figure 2. Overview of the anomalous mud pots in the