Two types of gabbroic xenoliths from rhyolite dominated Niijima volcano, northern part of Izu-Bonin arc: petrological and geochemical constraints
We examined the petrography, petrology, and geochemistry of two types of gabbroic xenoliths (A- and B-type xenoliths) in olivine basalt and biotite rhyolite units among the dominantly rhyolitic rocks in Niijima volcano, northern Izu-Bonin volcanic arc, central Japan. A-type gabbroic xenoliths consi...
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doaj-d54d9ee9f4d34ba894cb75f5b40b3cf42021-09-05T20:50:48ZengDe GruyterOpen Geosciences2391-54472017-03-019111210.1515/geo-2017-0001geo-2017-0001Two types of gabbroic xenoliths from rhyolite dominated Niijima volcano, northern part of Izu-Bonin arc: petrological and geochemical constraintsArakawa Yoji0Endo Daisuke1Ikehata Kei2Oshika Junya3Shinmura Taro4Mori Yasushi5Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanFaculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanFaculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanJapan Oil, Gas and Metal National Corporation, 2-10-1 Toranomon, Minato-ku, Tokyo105-0001, JapanFaculty of Economics, Kumamoto-Gakuen University, 2-5-1 Oe, Kumamoto, Kumamoto862-8680, JapanKitakyushu Museum of Natural History and Human History, 2-41 Yahatahigashi, Higashida, Kitakyushu, Fukuoka805-0071, JapanWe examined the petrography, petrology, and geochemistry of two types of gabbroic xenoliths (A- and B-type xenoliths) in olivine basalt and biotite rhyolite units among the dominantly rhyolitic rocks in Niijima volcano, northern Izu-Bonin volcanic arc, central Japan. A-type gabbroic xenoliths consisting of plagioclase, clinopyroxene, and orthopyroxene with an adcumulate texture were found in both olivine basalt and biotite rhyolite units, and B-type gabbroic xenoliths consisting of plagioclase and amphibole with an orthocumulate texture were found only in biotite rhyolite units. Geothermal- and barometricmodelling based on mineral chemistry indicated that the A-type gabbro formed at higher temperatures (899–955°C) and pressures (3.6–5.9 kbar) than the B-type gabbro (687–824°C and 0.8–3.6 kbar). These findings and whole-rock chemistry suggest different parental magmas for the two types of gabbro. The A-type gabbro was likely formed from basaltic magma, whereas the B-type gabbro was likely formed from an intermediate (andesitic) magma. The gabbroic xenoliths in erupted products at Niijima volcano indicate the presence of mafic to intermediate cumulate bodies of different origins at relatively shallower levels beneath the dominantly rhyolitic volcano.https://doi.org/10.1515/geo-2017-0001gabbroic xenolithniijima volcanocumulatecrystal fractionation |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Arakawa Yoji Endo Daisuke Ikehata Kei Oshika Junya Shinmura Taro Mori Yasushi |
spellingShingle |
Arakawa Yoji Endo Daisuke Ikehata Kei Oshika Junya Shinmura Taro Mori Yasushi Two types of gabbroic xenoliths from rhyolite dominated Niijima volcano, northern part of Izu-Bonin arc: petrological and geochemical constraints Open Geosciences gabbroic xenolith niijima volcano cumulate crystal fractionation |
author_facet |
Arakawa Yoji Endo Daisuke Ikehata Kei Oshika Junya Shinmura Taro Mori Yasushi |
author_sort |
Arakawa Yoji |
title |
Two types of gabbroic xenoliths from rhyolite dominated Niijima volcano, northern part of Izu-Bonin arc: petrological and geochemical constraints |
title_short |
Two types of gabbroic xenoliths from rhyolite dominated Niijima volcano, northern part of Izu-Bonin arc: petrological and geochemical constraints |
title_full |
Two types of gabbroic xenoliths from rhyolite dominated Niijima volcano, northern part of Izu-Bonin arc: petrological and geochemical constraints |
title_fullStr |
Two types of gabbroic xenoliths from rhyolite dominated Niijima volcano, northern part of Izu-Bonin arc: petrological and geochemical constraints |
title_full_unstemmed |
Two types of gabbroic xenoliths from rhyolite dominated Niijima volcano, northern part of Izu-Bonin arc: petrological and geochemical constraints |
title_sort |
two types of gabbroic xenoliths from rhyolite dominated niijima volcano, northern part of izu-bonin arc: petrological and geochemical constraints |
publisher |
De Gruyter |
series |
Open Geosciences |
issn |
2391-5447 |
publishDate |
2017-03-01 |
description |
We examined the petrography, petrology, and geochemistry of two types of gabbroic xenoliths (A- and B-type xenoliths) in olivine basalt and biotite rhyolite units among the dominantly rhyolitic rocks in Niijima volcano, northern Izu-Bonin volcanic arc, central Japan. A-type gabbroic xenoliths consisting of plagioclase, clinopyroxene, and orthopyroxene with an adcumulate texture were found in both olivine basalt and biotite rhyolite units, and B-type gabbroic xenoliths consisting of plagioclase and amphibole with an orthocumulate texture were found only in biotite rhyolite units. Geothermal- and barometricmodelling based on mineral chemistry indicated that the A-type gabbro formed at higher temperatures (899–955°C) and pressures (3.6–5.9 kbar) than the B-type gabbro (687–824°C and 0.8–3.6 kbar). These findings and whole-rock chemistry suggest different parental magmas for the two types of gabbro. The A-type gabbro was likely formed from basaltic magma, whereas the B-type gabbro was likely formed from an intermediate (andesitic) magma. The gabbroic xenoliths in erupted products at Niijima volcano indicate the presence of mafic to intermediate cumulate bodies of different origins at relatively shallower levels beneath the dominantly rhyolitic volcano. |
topic |
gabbroic xenolith niijima volcano cumulate crystal fractionation |
url |
https://doi.org/10.1515/geo-2017-0001 |
work_keys_str_mv |
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