Выпуск: 7 , Том: 57 , Год издания: 2016

In study of plagioclases, amphiboles, and melt inclusions, we have determined the physicochemical parameters of crystallization of melts in the intermediate suprasubduction chambers of volcanoes representing different types of subduction magmatism on the Kamchatka Peninsula: the young basaltic systems of Tolbachik Volcano (Klyuchevskaya group) and ancient Ichinskii Volcano (Sredinnyi Ridge) with alternating basaltic and felsic eruptions. For Tolbachik Volcano, we have found that plagioclase lapilli formed from basaltic melts at 1075-1115 degrees C and low (≤ 1 kbar) pressures at depths of 2-3 km. Andesite minerals crystallized within a wider range of temperatures and pressures (1220-1020 degrees C and 3.3-1.6 kbar) in an intermediate chamber at depths of ≤ 10 km. The melts were generated in basaltic magma chambers (detected well by geophysical methods at depths of 18-20 km) with minimum temperatures of similar to 1290 degrees C. For Ichinskii Volcano, three levels of intermediate chambers are distinguished. Andesites formed at depths of ≤ 23 km at ≤ 1225 degrees C. Dacitic melts were generated from an intermediate chamber (14 km) at 1135-1045 degrees C as a result of differentiation of andesitic magmas. Dacites formed in the uppermost horizons (9-3 km) at 1130-1030 degrees C.