Magma Plumbing System at Izu-Oshima Volcano, Japan: Constraints From Petrological and Geochemical Analyses

The Izu-Oshima volcano is one of the most active volcanoes in Japan, and has generated relatively large-scale eruptions every 30–40 years for the past 200 years. As more than 30 years have passed since the last eruptions in 1986–87, volcanic activity is expected to resume in the near future. To help...

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Main Authors: Takeshi Kuritani, Azusa Yamaguchi, Sayuki Fukumitsu, Mitsuhiro Nakagawa, Akiko Matsumoto, Tetsuya Yokoyama
Format: Article
Language:English
Published: Frontiers Media S.A. 2018-10-01
Series:Frontiers in Earth Science
Subjects:
Online Access:https://www.frontiersin.org/article/10.3389/feart.2018.00178/full
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spelling doaj-b15d82a3ca8343f08b8d62b4f7343a612020-11-24T21:48:26ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632018-10-01610.3389/feart.2018.00178415725Magma Plumbing System at Izu-Oshima Volcano, Japan: Constraints From Petrological and Geochemical AnalysesTakeshi Kuritani0Takeshi Kuritani1Azusa Yamaguchi2Sayuki Fukumitsu3Mitsuhiro Nakagawa4Akiko Matsumoto5Tetsuya Yokoyama6Graduate School of Science, Hokkaido University, Sapporo, JapanGraduate School of Science, Osaka City University, Osaka, JapanGraduate School of Science, Hokkaido University, Sapporo, JapanGraduate School of Science, Osaka City University, Osaka, JapanGraduate School of Science, Hokkaido University, Sapporo, JapanGraduate School of Science, Hokkaido University, Sapporo, JapanGraduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo, JapanThe Izu-Oshima volcano is one of the most active volcanoes in Japan, and has generated relatively large-scale eruptions every 30–40 years for the past 200 years. As more than 30 years have passed since the last eruptions in 1986–87, volcanic activity is expected to resume in the near future. To help elucidate the current and future state of the volcano’s magma system, the temporal evolution of the recent magma plumbing system was investigated through a petrological and geochemical analysis of its basaltic lavas and pyroclastics (<∼53 wt.% of SiO2) that were erupted during the last ∼1.5 kyr. The basaltic products have variable phenocryst contents, ranging from ∼0 to ∼20 vol.%, and phenocryst-bearing samples commonly contain plagioclase, orthopyroxene, and clinopyroxene phenocrysts. The whole-rock compositions are significantly scattered in the Harker variation diagrams, suggesting that the compositional diversity was established by at least two independent magmatic processes. The application of principal component analysis on the whole-rock major element data suggests that one magmatic process was crystal fractionation of crystal-poor magmas, and the other process was either plagioclase accumulation or mixing of plagioclase-rich magmas. Based on this observation, and combined with the petrological analysis and previous geophysical studies, we propose that aphyric magmas, stored in an 8–10 km-deep magma chamber, progressively differentiated over time from the 7th to 20th century. Furthermore, the compositional variations in basalts resulted from the mixing of the differentiating aphyric magmas with variable proportions of porphyritic magmas derived from a 13–18 km-deep magma chamber. Because recent eruptions have been triggered by the ascent of porphyritic magma from the 13–18 km-deep magma chamber, and its injection into the 8–10 km-deep magma chamber, it is important to monitor the deeper magma chamber to predict future volcanic activity.https://www.frontiersin.org/article/10.3389/feart.2018.00178/fullactive volcanoIzu-Oshima volcanomagma mixingmagma plumbing systemprincipal component analysis
collection DOAJ
language English
format Article
sources DOAJ
author Takeshi Kuritani
Takeshi Kuritani
Azusa Yamaguchi
Sayuki Fukumitsu
Mitsuhiro Nakagawa
Akiko Matsumoto
Tetsuya Yokoyama
spellingShingle Takeshi Kuritani
Takeshi Kuritani
Azusa Yamaguchi
Sayuki Fukumitsu
Mitsuhiro Nakagawa
Akiko Matsumoto
Tetsuya Yokoyama
Magma Plumbing System at Izu-Oshima Volcano, Japan: Constraints From Petrological and Geochemical Analyses
Frontiers in Earth Science
active volcano
Izu-Oshima volcano
magma mixing
magma plumbing system
principal component analysis
author_facet Takeshi Kuritani
Takeshi Kuritani
Azusa Yamaguchi
Sayuki Fukumitsu
Mitsuhiro Nakagawa
Akiko Matsumoto
Tetsuya Yokoyama
author_sort Takeshi Kuritani
title Magma Plumbing System at Izu-Oshima Volcano, Japan: Constraints From Petrological and Geochemical Analyses
title_short Magma Plumbing System at Izu-Oshima Volcano, Japan: Constraints From Petrological and Geochemical Analyses
title_full Magma Plumbing System at Izu-Oshima Volcano, Japan: Constraints From Petrological and Geochemical Analyses
title_fullStr Magma Plumbing System at Izu-Oshima Volcano, Japan: Constraints From Petrological and Geochemical Analyses
title_full_unstemmed Magma Plumbing System at Izu-Oshima Volcano, Japan: Constraints From Petrological and Geochemical Analyses
title_sort magma plumbing system at izu-oshima volcano, japan: constraints from petrological and geochemical analyses
publisher Frontiers Media S.A.
series Frontiers in Earth Science
issn 2296-6463
publishDate 2018-10-01
description The Izu-Oshima volcano is one of the most active volcanoes in Japan, and has generated relatively large-scale eruptions every 30–40 years for the past 200 years. As more than 30 years have passed since the last eruptions in 1986–87, volcanic activity is expected to resume in the near future. To help elucidate the current and future state of the volcano’s magma system, the temporal evolution of the recent magma plumbing system was investigated through a petrological and geochemical analysis of its basaltic lavas and pyroclastics (<∼53 wt.% of SiO2) that were erupted during the last ∼1.5 kyr. The basaltic products have variable phenocryst contents, ranging from ∼0 to ∼20 vol.%, and phenocryst-bearing samples commonly contain plagioclase, orthopyroxene, and clinopyroxene phenocrysts. The whole-rock compositions are significantly scattered in the Harker variation diagrams, suggesting that the compositional diversity was established by at least two independent magmatic processes. The application of principal component analysis on the whole-rock major element data suggests that one magmatic process was crystal fractionation of crystal-poor magmas, and the other process was either plagioclase accumulation or mixing of plagioclase-rich magmas. Based on this observation, and combined with the petrological analysis and previous geophysical studies, we propose that aphyric magmas, stored in an 8–10 km-deep magma chamber, progressively differentiated over time from the 7th to 20th century. Furthermore, the compositional variations in basalts resulted from the mixing of the differentiating aphyric magmas with variable proportions of porphyritic magmas derived from a 13–18 km-deep magma chamber. Because recent eruptions have been triggered by the ascent of porphyritic magma from the 13–18 km-deep magma chamber, and its injection into the 8–10 km-deep magma chamber, it is important to monitor the deeper magma chamber to predict future volcanic activity.
topic active volcano
Izu-Oshima volcano
magma mixing
magma plumbing system
principal component analysis
url https://www.frontiersin.org/article/10.3389/feart.2018.00178/full
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