TY - JOUR

T1 - High explosivity of the June 21, 2019 eruption of Raikoke volcano (Central Kuril Islands); mineralogical and petrological constraints on the pyroclastic materials

AU - Smirnov, S. Z.

AU - Nizametdinov, I. R.

AU - Timina, T. Yu

AU - Kotov, A. A.

AU - Sekisova, V. S.

AU - Kuzmin, D. V.

AU - Kalacheva, E. G.

AU - Rashidov, V. A.

AU - Rybin, A. V.

AU - Lavrenchuk, A. V.

AU - Degterev, A. V.

AU - Maksimovich, I. A.

AU - Abersteiner, Adam

N1 - Funding Information: This study was partially performed within the framework of the state assignment of the Sobolev Institute of Geology and Mineralogy SB RAS (Novosibirsk), Institute of Volcanology and Seismology FEB RAS (Petropavlovsk-Kamchatsky), and Institute of Marine Geology and Geophysics FEB RAS (Yuzhno-Sakhalinsk). Analytical studies were partially performed within the framework of Russian Foundation for Basic Research grants 18-05-00819 , 18-05-00410 , 19-35-90038 , and Russian Science Foundation grant 20-17-00075 . Funding Information: This study was partially performed within the framework of the state assignment of the Sobolev Institute of Geology and Mineralogy SB RAS (Novosibirsk), Institute of Volcanology and Seismology FEB RAS (Petropavlovsk-Kamchatsky), and Institute of Marine Geology and Geophysics FEB RAS (Yuzhno-Sakhalinsk). Analytical studies were partially performed within the framework of Russian Foundation for Basic Research grants 18-05-00819, 18-05-00410, 19-35-90038, and Russian Science Foundation grant 20-17-00075. Publisher Copyright: © 2021 Elsevier B.V. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/10

Y1 - 2021/10

N2 - The small volcanic islands of the central Greater Kuril Chain (GKC) produce strong explosive eruptions, two of which occurred in the recent years. The latest eruption took place at Raikoke volcano, which occurred on June 21–25 (2019) and was one of the largest on the Kuril Islands in the 21st century. This study presents mineralogical, petrographic and geochemical data on the air fall ash and pyroclastic density current deposits to elucidate the causes of high explosivity of this eruption. The magma involved in the Raikoke volcanic eruption is likely to have had a mantle origin and basaltic composition. Prior to forming a near-surface reservoir, the magma fractionated (i.e. due to crystallization of olivine and pyroxene) at depths of about 26 km, which is close to the Moho discontinuity in the middle part of GKC. The presence of amphibole among the 2019 pyroclastic minerals indicates that the magma contained significant (i.e. no less than 4 wt%) amounts of water at depth. This magma was degassed prior to intrusion into a shallower reservoir. The magma in the shallow reservoir had high crystallinity and contained viscous felsic residual melts, which prevented the development of effusive eruptions or Strombolian explosions. It is likely that magmatic fluid bubbles were still present, but their abundance was insufficient for lava fragmentation in the conduit. This led to low degree of vesiculation of the erupting melts. The results of this study demonstrate that the explosivity of the eruption is most likely related to the interaction in the volcanic edifice between meteoric waters and the magma, which was largely degassed and contained significant amounts of crystals and felsic melt (i.e. had high viscosity and low mobility).

AB - The small volcanic islands of the central Greater Kuril Chain (GKC) produce strong explosive eruptions, two of which occurred in the recent years. The latest eruption took place at Raikoke volcano, which occurred on June 21–25 (2019) and was one of the largest on the Kuril Islands in the 21st century. This study presents mineralogical, petrographic and geochemical data on the air fall ash and pyroclastic density current deposits to elucidate the causes of high explosivity of this eruption. The magma involved in the Raikoke volcanic eruption is likely to have had a mantle origin and basaltic composition. Prior to forming a near-surface reservoir, the magma fractionated (i.e. due to crystallization of olivine and pyroxene) at depths of about 26 km, which is close to the Moho discontinuity in the middle part of GKC. The presence of amphibole among the 2019 pyroclastic minerals indicates that the magma contained significant (i.e. no less than 4 wt%) amounts of water at depth. This magma was degassed prior to intrusion into a shallower reservoir. The magma in the shallow reservoir had high crystallinity and contained viscous felsic residual melts, which prevented the development of effusive eruptions or Strombolian explosions. It is likely that magmatic fluid bubbles were still present, but their abundance was insufficient for lava fragmentation in the conduit. This led to low degree of vesiculation of the erupting melts. The results of this study demonstrate that the explosivity of the eruption is most likely related to the interaction in the volcanic edifice between meteoric waters and the magma, which was largely degassed and contained significant amounts of crystals and felsic melt (i.e. had high viscosity and low mobility).

KW - Kuril Islands

KW - Mineralogy

KW - Petrology

KW - Phreatomagmatic eruption

KW - Raikoke volcano

UR - http://www.scopus.com/inward/record.url?scp=85110443183&partnerID=8YFLogxK

U2 - 10.1016/j.jvolgeores.2021.107346

DO - 10.1016/j.jvolgeores.2021.107346

M3 - Article

AN - SCOPUS:85110443183

VL - 418

JO - Journal of Volcanology and Geothermal Research

JF - Journal of Volcanology and Geothermal Research

SN - 0377-0273

M1 - 107346

ER -