Magma plumbing system of the 2000 eruption of Miyakejima volcano, Japan, deduced from volatile and major component contents of olivine‐hosted melt inclusions

Saito, Genji; Morishita, Y.; Shinohara, Hiroshi

doi:10.1029/2010jb007433

Cited by 26 publications

(31 citation statements)

References 58 publications

(188 reference statements)

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“…8). Melt inclusion analyses suggests that the H 2 O and S contents of the bulk magma are about 2 wt.% and 500 ppm (Saito et al, 2011), implying that the H 2 O/S mol ratio of the bulk magma is 70, which is similar to other persistently degassing volcanoes, such as the Satsuma-Iwojima and Miyakejima volcanoes (Saito et al, 2001(Saito et al, , 2010. The S-poor volcanic gas composition of the Shinmoedake can be due to high-pressure degassing.…”

Section: Chemical Compositionsupporting

confidence: 49%

Composition of volcanic gases emitted during repeating Vulcanian eruption stage of Shinmoedake, Kirishima volcano, Japan

Shinohara

2013

Earth Planet Sp

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Volcanic gas compositions of Shinmoedake, Kirishima volcano, Japan were measured by Multi-GAS during the persistent degassing period with repeating Vulcanian eruptions from March 2011 to March 2012. In order to avoid risks due to eruptions, the measurements were performed with the Unmanned Aerial Vehicles (UAV) that fly through the plume with the Multi-GAS and by an automatic Multi-GAS monitoring station installed 5 km away from the summit. Based on the UAV measurements on May 18, 2011, most of the major volcanic gas components were quantified as CO 2 /SO 2 = 8, SO 2 /H 2 S = 0.8, H 2 O/CO 2 = 70 and H 2 /SO 2 = 0.03 (mol ratio), and the SO 2 /H 2 S ratio of the plume was quantified as 8 on March 15, 2011. The Multi-GAS monitoring station occasionally detected a dilute plume with an SO 2 /H 2 S ratio ranging from 0.8 to 3.3 from April 2011 to March 2012. The decrease of the SO 2 /H 2 S ratio from March 15, 2011, to May 18, 2011, is interpreted as the result of a ten times increase of the degassing pressure. Based on the SO 2 fluxes and the gas compositions, the conduit magma convection is considered to be the gas supply mechanism at the Shinmoedake, and the degassing pressure changes are attributed to the change of depth of the convecting magma column top.

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Section: Chemical Compositionsupporting

confidence: 49%

Composition of volcanic gases emitted during repeating Vulcanian eruption stage of Shinmoedake, Kirishima volcano, Japan

Shinohara

2013

Earth Planet Sp

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“…On the contrary, recent melt inclusion studies (e.g. Sisson and Layne 1993;Newman et al 2000;Saito et al 2005Saito et al , 2010Ikehata et al 2010) indicated that the H 2 O content in tholeiitic basaltic melt is larger than 3 wt.% at the volcanic front.…”

Section: Introductionmentioning

confidence: 77%

“…In the case of Izu-Oshima volcano, the maximum H 2 O content of melt inclusions in the olivine phenocrysts was 3.4 wt.% by analysis of products of the older Oshima group (Ikehata et al 2010). In the case of Miyakejima volcano, Saito et al (2005Saito et al ( , 2010 analyzed melt inclusions of plagioclase and olivine phenocrysts from the AD 2000 eruption and estimated the H 2 O content to be 3.3 wt.% in olivine-hosted melt inclusions. These analyses are consistent with the values of pre-eruptive H 2 O content in melt estimated in this study.…”

Section: Pre-eruptive H 2 O Content In Arc Basalt Magmasmentioning

confidence: 99%

Water content in arc basaltic magma in the Northeast Japan and Izu arcs: an estimate from Ca/Na partitioning between plagioclase and melt

Ushioda

Takáhashi

Hamada

et al. 2014

Earth, Planets and Space

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The variation in water content of arc basaltic magmas in the Northeast Japan arc and the Izu arc was estimated using a simple plagioclase phenocryst hygrometer. In order to construct a plagioclase phenocryst hygrometer optimized for arc basalt magmas, we have conducted high-pressure melting experiments of relatively primitive basalt from the Miyakejima volcano, a frontal-arc volcano in the Izu arc. As a result of the experiments, we found that the Ca/Na partition coefficient between plagioclase and hydrous basaltic melt increases linearly with an increase in H 2 O content in the melts. We then selected from literature geochemical data sets of relatively primitive basaltic rocks with no evidence of magma mixing and the most frequent Ca-rich plagioclase phenocrysts from 15 basaltic arc volcanoes including both frontal-arc and rear-arc volcanoes. In the 15 volcanoes studied, plagioclase phenocrysts of high anorthite content (An > 90) were commonly observed, whereas plagioclase phenocrysts in rear arc volcanoes usually had a lower anorthite content (90 > An > 80). In all volcanoes studied, the estimated H 2 O content of basaltic magma was at least 3 wt.% H 2 O or higher. The magmas of volcanoes located on the volcanic front have about 5 wt.% H 2 O in magma whereas those from the rear-arc side are slightly lower in H 2 O content.

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“…H 2 O versus CO 2 diagram for melt inclusions in the Ofunato scoria. Data for melt inclusions in the products of the AD2000 eruption are shown for comparison (Saito et al, ).…”

Section: Resultsmentioning

confidence: 99%

Evolution of Magma Plumbing System in Miyakejima Volcano: Constraints From Melting Experiments

et al. 2018

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The evolution of the magma plumbing system of Miyakejima volcano, an island arc basaltic volcano located on the volcanic front of the Izu arc, Japan, was investigated by combining (i) melting experiments of hydrous basaltic magma, (ii) analysis of melt inclusions in the volcanic rocks, and (iii) thermodynamic modeling using the thermodynamic program (MELTS) to understand the temporal evolution of the magma plumbing system. Basalts of the Ofunato Stage (10,000–4,000 year BP) show limited compositional variation without evidence of magma mixing, and seem to be parental to volcanic rocks of later stages. Hydrous melting experiments were conducted using the Ofunato Scoria (OFS), which represents the most undifferentiated basaltic magma during the past 10,000 years. The magma chamber conditions required to crystallize the phenocryst assemblage of the OFS were constrained to ~150 MPa, ~1100 °C, and ~3 wt% H2O in melt. The constrained H2O content is consistent with H2O content of olivine‐hosted melt inclusions in the OFS. Here we propose that a simple magma plumbing system existed beneath Miyakejima volcano during the Ofunato Stage, comprising a single magma chamber. The MELTS calculations show that andesites of the Tsubota Stage (4,000–2,500 year BP; representing the later part of the Ofunato Stage after a period of dormancy of 3,000 years), can be derived from the Ofunato basalts, provided that H2O content in magma is <1 wt%. The results of modeling indicate that a new magma chamber formed at a shallower depth after the Ofunato Stage, in which the differentiation of degassed basaltic magmas occurred.

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Magma plumbing system of the 2000 eruption of Miyakejima volcano, Japan, deduced from volatile and major component contents of olivine‐hosted melt inclusions

Cited by 26 publications

References 58 publications

Composition of volcanic gases emitted during repeating Vulcanian eruption stage of Shinmoedake, Kirishima volcano, Japan

Composition of volcanic gases emitted during repeating Vulcanian eruption stage of Shinmoedake, Kirishima volcano, Japan

Water content in arc basaltic magma in the Northeast Japan and Izu arcs: an estimate from Ca/Na partitioning between plagioclase and melt

Evolution of Magma Plumbing System in Miyakejima Volcano: Constraints From Melting Experiments

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