Geological Structure Features and Rocks Composition of Kronotsky Volcano, the Largest Stratovolcano in the Frontal Zone of the Eastern Volcanic Belt of Kamchatka

Abstract

Based on the results of 2020‒2022 field works, this paper presents a characterization of the geological structure and whole rock composition of Kronotsky volcano, one of the poorly studied eruptive centers of the Eastern Volcanic Belt (EVB) of Kamchatka. The volume of the volcanic edifice is estimated at 350 km3, that significantly exceeds the volumes of other stratovolcanoes of the frontal zone of EVB. Rocks of a volcano are presented by low-K, high-Fe tholeiitic basalts and basaltic andesites (SiO2 = 47.04–53.15 wt %; K2O = = 0.24‒0.65 wt %; FeO*/MgO = 1.2‒2.89). The basalts show extremely low contents of silica, potassium, titanium, and phosphorus in comparison with rocks of other frontal volcanoes of Kamchatka. The revealed petrochemical features were used to clarify the belonging of the objects located at the junction of Kronotsky and Krasheninnikov volcanic edifices. The obtained data will serve as the background for further petrological and geochemical studies of the volcano, and also may be used for reconstruction the sequence of volcanic events in this area, including clarification of the history of Kronotsky Lake formation.