Petrology and geochemistry of the Tolbachik stratovolcano

The numerous of national and international publications were dedicated to Plosky Tolbachik volcano eruptions and adjacent monogenetic cones, which were erupted repeatedly during Holocene, including historical time [i.e. Vlodavets, 1937; Popkov, 1946; Peep, 1946, 1954; Menyailov, 1953; Sirin and Farberov, 1963; Kirsanov et al., 1974; Ivanov and Khrenov, 1979; Fedotov, 1984; Krivenko, 1990; Kersting, 1995; Tatsumi et al., 1995; Hochstaedter et al., 1996; Kepezhinskas et al., 1997; Turner et al., 1998; Pineau et al., 1999; Volynets et al., 2000; Churikova et al., 2001; Münker et al., 2004; Portnyagin et al., 2007; Volynets et al., 2013]. However, all these data mainly relates to monogenetic cones, but the information on stratovolcanoes itself practically absent. There are only few papers on Ostry and Plosky Tolbachik stratovolcanoes focusing on geology [Ermakov and Vazheevskaya, 1973], petrography and some petrochemistry of the rocks [Ermakov, 1977; Flerov and Melekestsev, 2013]. The modern geochemical and isotope studies of the stratovolcanoes were never achieved. In this report we present geological, petrographical, petrochemical, geochemical and some K-Ar data on the rocks of Tolbachik massif. The present report based on representative collection of 154 samples from stratovolcanoes, dikes, monogenetic cones of different ages, including last 2012-2013 eruption. Additionally our study included samples separately standing edifice of Povorotnaya mount, which age according to K-Ar dating is 0.306±0.01 Ма