TY - JOUR

T1 - Physicochemical parameters of crystallization of melts in intermediate suprasubduction chambers (by the example of Tolbachik and Ichinskii Volcanoes, Kamchatka Peninsula)

AU - Dobretsov, N. L.

AU - Simonov, V. A.

AU - Kotlyarov, A. V.

AU - Kulakov, R. Yu

AU - Karmanov, N. S.

PY - 2016/7/1

Y1 - 2016/7/1

N2 - 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 °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 °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 ~ 1290 °C. For Ichinskii Volcano, three levels of intermediate chambers are distinguished. Andesites formed at depths of < 23 km at < 1225 °C. Dacitic melts were generated from an intermediate chamber (14 km) at 1135-1045 °C as a result of differentiation of andesitic magmas. Dacites formed in the uppermost horizons (9-3 km) at 1130-1030 °C. Despite the similarity between differentiation processes in the intermediate chambers of the Kamchatka volcanoes, each volcano is characterized by specific magmatism. The lavas of basaltic volcanoes (Tolbachik) and those of andesitic volcanoes (Ichinskii) differ in genesis and differentiation.

AB - 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 °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 °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 ~ 1290 °C. For Ichinskii Volcano, three levels of intermediate chambers are distinguished. Andesites formed at depths of < 23 km at < 1225 °C. Dacitic melts were generated from an intermediate chamber (14 km) at 1135-1045 °C as a result of differentiation of andesitic magmas. Dacites formed in the uppermost horizons (9-3 km) at 1130-1030 °C. Despite the similarity between differentiation processes in the intermediate chambers of the Kamchatka volcanoes, each volcano is characterized by specific magmatism. The lavas of basaltic volcanoes (Tolbachik) and those of andesitic volcanoes (Ichinskii) differ in genesis and differentiation.

KW - basalt and andesite minerals

KW - intermediate suprasubduction chambers

KW - Kamchatka volcanoes

KW - melt inclusions

KW - physicochemical parameters of crystallization

UR - http://www.scopus.com/inward/record.url?scp=84991032287&partnerID=8YFLogxK

U2 - 10.1016/j.rgg.2016.06.001

DO - 10.1016/j.rgg.2016.06.001

M3 - Article

AN - SCOPUS:84991032287

VL - 57

SP - 993

EP - 1015

JO - Russian Geology and Geophysics

JF - Russian Geology and Geophysics

SN - 1068-7971

IS - 7

ER -