Presentations -
about 150-
The pressure-temperature conditions of garnet-orthopyroxene granulite from Oku-iwa Rock in the Lützow-Holm Complex, East Antarctica
Ippei Kitano, Tsuyoshi Toyoshima, Masahiro Ishikawa and Takuma Katori
The 15th Symposium on Polar Science National Institute of Polar Research Research Organization of Information and Systems
Event date: 2024.12
Language:English Presentation type:Oral presentation (general)
Venue:Tachikawa, Tokyo
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Seismic imaging of the crust and lithospheric mantle of the Pan-African mobile belt, the Lützow-Holm Complex, East Antarctica
Masaki Kanao, Shigeru Toda and Masahiro Ishikawa
The 15th Symposium on Polar Science National Institute of Polar Research Research Organization of Information and Systems
Event date: 2024.12
Language:English Presentation type:Oral presentation (general)
Venue:Tachikawa, Tokyo
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島弧地殻深部岩石と温度構造
石川 正弘、松本 拓己
日本地球惑星科学連合
Event date: 2023.5
Language:English Presentation type:Oral presentation (general)
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人新世のリスク:環境・都市・社会
石川 正弘、板垣 春香、才畑 真子、関戸 一樹
日本地球惑星科学連合
Event date: 2023.5
Language:Japanese Presentation type:Oral presentation (general)
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Planetary Boundaries and Society
ISHIKAWA Masahiro
Annual Meeting of the Geological Society of Japan 2022.9 The Geological Society of Japan
Event date: 2022.9
Language:Japanese Presentation type:Other
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Risk transfer to the future
2022.5
Event date: 2022.5 - 2022.6
Language:Japanese Presentation type:Poster presentation
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グローバルサウスにおける都市ヒートアイランド
才畑 真子、石川 正弘
日本地球惑星科学連合2022年大会 2022.5 日本地球惑星科学連合
Event date: 2022.5 - 2022.6
Language:Japanese Presentation type:Oral presentation (general)
Venue:千葉県千葉市幕張メッセ
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衛星リモートセンシングによる都市化の熱環境への影響評価
才畑 真子、石川 正弘
日本地球惑星科学連合2022年大会 2022.5 日本地球惑星科学連合
Event date: 2022.5 - 2022.6
Language:Japanese Presentation type:Oral presentation (general)
Venue:千葉県千葉市幕張メッセ
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人新世の地球システム論:環境・都市・社会の複眼的視点
石川正弘
日本地球惑星科学連合2022年大会 2022.5 日本地球惑星科学連合
Event date: 2022.5 - 2022.6
Language:Japanese Presentation type:Poster presentation
Venue:千葉県千葉市幕張メッセ
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東南極大陸アメリー棚氷における氷河上湖の分布と季節変化
板垣 春香、石川 正弘
日本地球惑星科学連合2022年大会 2022.5 日本地球惑星科学連合
Event date: 2022.5 - 2022.6
Language:Japanese Presentation type:Poster presentation
Venue:千葉県千葉市幕張メッセ
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Thermal structure of southwest Honshu arc estimated from seismic velocities
2022.5
Event date: 2022.5 - 2022.6
Language:Japanese Presentation type:Oral presentation (general)
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複眼的思考から読み解くパラグアイのスラム~コミュニティ・国家・南米大陸~
藤掛 洋子、田中 伸治、松本 由香、三浦 倫平、石川 正弘
第5回都市科学シンポジウム 2022.2 横浜国立大学都市科学部
Event date: 2022.2
Language:Japanese Presentation type:Symposium, workshop panel (nominated)
Venue:横浜
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Distribution and seasonal evolution of supraglacial lakes around Lutzow-Holm Bay, East Antarctica
Haruka Itagaki, Masahiro Ishikawa
The 12th Symposium on Polar Science 2021.11 Inter-university Research Institute Corporation Research Organization of Information and Systems National Institute of Polar Research
Event date: 2021.11
Language:English Presentation type:Poster presentation
Venue:オンライン
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日本列島の地殻内部の温度構造と脆性塑性境界深度
石川正弘
日本地質学会 2021.9 日本地質学会
Event date: 2021.9
Language:Japanese Presentation type:Poster presentation
Venue:オンライン
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地震波速度温度計による東北本州弧地殻の温度構造:高精度な熱構造の解明に向けて
石川正弘
日本地質学会 2021.9 日本地質学会
Event date: 2021.9
Language:Japanese Presentation type:Oral presentation (general)
Venue:オンライン
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Elastic properties of fine-grained polycrystalline clinopyroxene under high P-T conditions
Yumiko Tsubokawa, Masahiro Ishikawa
日本地球惑星科学連合2022年大会 2021.6 日本地球惑星科学連合
Event date: 2021.5 - 2021.6
Language:English Presentation type:Poster presentation
Venue:オンライン
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本州弧地殻の温度構造:地震波トモグラフィーからの推定
石川正弘
日本地球惑星科学連合2022年大会 2021.6 日本地球惑星科学連合
Event date: 2021.5 - 2021.6
Language:Japanese Presentation type:Oral presentation (general)
Venue:オンライン
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The thermal structure of the NE Honshu arc crust: insight from P-wave and S-wave velocities
Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan 2021 The Geological Society of Japan
Event date: 2021
Language:Japanese Presentation type:Other
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The thermal structure and brittle-ductile transition depth in the Japanese islands
Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan 2021 The Geological Society of Japan
Event date: 2021
Language:Japanese Presentation type:Other
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Pseudotachylytes from Langhovde and Skarvsnes in the Lützow-Holm Complex, East Antarctica, and their conditions of formation
Tsuyoshi Toyoshima,Masahiro Ishikawa,Ippei Kitano,Takuma Katori
The Tenth symposium on Polar Science
Event date: 2019.12
Language:English Presentation type:Poster presentation
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Geological field survey in the regions of Lutzow-Holm Bay, Prince Olav Coast and Enderby Land, 2018-2019 (JARE- 60)
Tsuyoshi Toyoshima,Masahiro Ishikawa,Ippei Kitano,Takuma Katori<Tomokazu Hokada
The Tenth symposium on Polar Science
Event date: 2019.12
Language:English Presentation type:Oral presentation (general)
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Links between global magmatism and GIA -Future plan-
Tatsuo Kanamaru,Kenichiro Tani,Masahiro Ishikawa,Kuniyuki Furukawa,Masakazu Fujii,Osamu Ishizuka,Jun'ichi Okuno
The Tenth symposium on Polar Science
Event date: 2019.12
Language:English Presentation type:Poster presentation
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東北本州弧の熱構造:地震波トモグラフィ からの推定
石川正弘
日本地質学会第126年学術大会 日本地質学会
Event date: 2019.9
Language:Japanese Presentation type:Poster presentation
Venue:山口
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スリランカ・ハイランド岩体に産する高温変成岩中のザクロ 石・ジルコン希土類元素組成
東野文子,廣井美邦,本吉洋 一,石川正弘,小林記之,本多聡子,プレーム バーナード,青木一勝,青木翔吾
日本地質学会第126年学術大会 日本地質学会
Event date: 2019.9
Language:Japanese Presentation type:Poster presentation
Venue:山口
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Laboratory Measurements of Vp, Vs and Vp/Vs for polycrystalline labradorite up to 800°C and 1GPa
本多聡子、石川正弘
日本地球惑星科学連合
Event date: 2019.5
Language:Japanese Presentation type:Oral presentation (general)
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Higashino Fumiko, Hiroi Yoshikuni, Motoyoshi Yoichi, Ishikawa Masahiro, Kobayashi Tomoyuki, Honda Satoko, Prame Bernard, Aoki Kazumasa, Aoki Syogo
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2019
Language:Japanese Presentation type:Other
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Thermal structure of the Northeast Honshu arc inferred from seismic tomography
Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2019
Language:Japanese Presentation type:Other
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高温変成作用下における塩水流入時の物質移動・鉱物組成変化プロセス
東野 文子, 河上 哲生, 土屋 範芳, サティシュ クマール, 石川 正弘, グランサム ジェフ, 坂田 周平, 平田 岳史
日本地質学会学術大会
Event date: 2018.9
Language:Japanese Presentation type:Oral presentation (general)
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Elastic wave velocity change caused lawsonite decomposition in blueschist at 1.0GPa and up to 550℃
櫻木颯,石川正弘
日本地球惑星科学連合
Event date: 2018.5
Language:Japanese Presentation type:Poster presentation
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Ultrasonic velocity measurements of plycrystalline clinopyroxene under high P-T conditions
坪川祐美子,石川正弘
日本地球惑星科学連合
Event date: 2018.5
Language:Japanese Presentation type:Poster presentation
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石川正弘
日本地球惑星科学連合
Event date: 2018.5
Language:Japanese Presentation type:Oral presentation (general)
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佐藤 比呂志,石山 達也,橋間 昭徳,岩崎 貴哉,松原 誠*佐藤 比呂志1、石山達也,橋間昭徳,岩崎貴哉,松原誠,篠原雅尚,石川正弘
日本地球惑星科学連合
Event date: 2018.5
Language:Japanese Presentation type:Oral presentation (general)
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最大1.0GPa、800℃条件下における曹灰長石多結晶体の弾性波速度測定
本多 聡子, 石川 正弘
日本鉱物科学会年会 日本鉱物科学会
Event date: 2018
Language:Japanese Presentation type:Poster presentation
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Sintering of nanocrystalline olivine aggregates
Tsubokawa Yumiko, Ishikawa Masahiro
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences Japan Association of Mineralogical Sciences
Event date: 2017
Language:Japanese Presentation type:Other
We described the sintering behavior of polycrystalline olivine. Nano-sized olivine powders were successfully fabricated from naturally occurring olivine single crystal. They were sintered under argon flow at temperatures ranging from 1130-1300 °C for 2-6 h. Polycrystalline olivine showed a homogeneous texture and almost random crystallographic preferred orientation. The average grain size increased with increasing sintering time and sintering temperature. Normalized grain size distributions have a unimodal distribution and show no systematic change.
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The relationship between crustal lithology and fault slip and aftershock distributions
Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2017
Language:Japanese Presentation type:Other
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Higashino Fumiko, Kawakami Tetsuo, Tsuchiya Noriyoshi, M. Satish-Kumar, Ishikawa Masahiro, Grantham Geoffrey, Sakata Shuhei, Hirata Takafumi
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2016
Language:Japanese Presentation type:Other
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Honda Satoko, Ishikawa Masahiro
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences Japan Association of Mineralogical Sciences
Event date: 2016
Language:Japanese Presentation type:Other
Lithological interpretation of crust beneath the Japan islands is important to understand the crustal evolution of the Honshu arc. We collected the rock samples from the Shimanto and Chichibu belts and measured Vp and Vs up to 1.0 GPa in a temperature range of 25-450°C in a piston cylinder apparatus. We then compared the rock velocities with the seismic velocity profiles, and inferred that the Shimanto and Chichibu belts are distributed at depths shallower than 10km in the Kanto Mountains.
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Kawakami Tetsuo, Higashino Fumiko, Skrzypek Etienne, Satish-Kumar M., Grantham Geoffrey H., Tsuchiya Noriyoshi, Ishikawa Masahiro, Sakata Shuhei, Hirata Takafumi
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2016
Language:Japanese Presentation type:Other
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Elastic wave velocities of polycrystalline labradorite under high pressures and high temperatures
Honda Satoko, Ishikawa Masahiro
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences Japan Association of Mineralogical Sciences
Event date: 2016
Language:Japanese Presentation type:Other
Plagioclase is a major constituent mineral in the Earth's crust .We prepared the samples of polycrystalline labradorite and measured compressional wave velocities (Vp) and shear (Vs) wave velocities. Ultrasonic measurements on these samples were conducted up to 1.0 GPa in a temperature range of 25-450°C in a piston cylinder apparatus.
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High temperature deformation experiments of sintered nano-polycrystalline clinopyroxene
Ishikawa Masahiro, Tsubokawa Yumiko
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2016
Language:Japanese Presentation type:Other
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Sintering of nanocrystalline clinopyroxene
Tsubokawa Yumiko, Ishikawa Masahiro
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences Japan Association of Mineralogical Sciences
Event date: 2016
Language:Japanese Presentation type:Other
Fine-grained polycrystalline diopside and polycrystalline salite were prepared from nano-sized clinopyroxene powders. Clinopyroxene powders fabricated from two types of clinopyroxene single crystal (diopside, salite) are sintered under argon flow at temperatures of 1130-1280 deg C for 2-6h. As a result, high density polycrystalline diopside and polycrystalline salite with an average grain size of <500nm are obtained at a sintering temperature of 1180 deg C and 1130 deg C, respectively.
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Sintering of nano-sized polycrystalline clinopyroxene
Tsubokawa Yumiko, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2016
Language:Japanese Presentation type:Other
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ICHIKI Takashi, ISHIKAWA Masahiro, KIMURA Jun–Ichi, SENDA Ryoko, RAKOTONDRAZAFY Raymond
岩石礦物礦床學 一般社団法人 日本鉱物科学会
Event date: 2015
Language:English Presentation type:Other
In reconstructions of the Gondwana supercontinent, correlations of Archean domains between Madagascar and India remain debated. In this paper, we aim to establish correlations among these Archean domains using whole–rock geochemistry and U–Pb zircon geochronology of meta–granitoids from the Masora and the Antananarivo domains, central–eastern Madagascar. A meta–granitoid from the central part of Masora domain is dated at 3277 Ma and shows a typical Archean tonalite–trondhjemite–granodiorite composition, whereas a tonalitic gneiss from the southeastern part of the Antananarivo domain gives an age of 2744 Ma. The geochemical signature of this tonalitic gneiss differs from that of the ~ 2500 Ma granitoids of the northwestern part of Antananarivo domain. In addition, the geochemical composition of the ~ 760 Ma granitic gneisses is consistent with a volcanic–arc origin for the protolith. Based on the geochemical and geochronological results, along with existing data, we identified three episodes of granitic magmatism in central–eastern Madagascar at ~ 3300, 2700, and 2500 Ma. These three magmatic events are consistent with those reported for the Dharwar Craton in India, suggesting that the Archean Masora and Antananarivo domains in Madagascar were part of the Greater Dharwar Craton during the period of 3300–2500 Ma. The 700–800 Ma volcanic arc granites identified in eastern Madagascar have not been reported in India. Therefore, the subduction of the oceanic plate that led to the formation of these granites likely took place at the western margin of the Greater Dharwar Craton, which included part of eastern Madagascar.
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Honda Satoko, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2015
Language:The in addition, foreign language Presentation type:Other
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Higashino Fumiko, Kawakami Tetsuo, Tsuchiya Noriyoshi, Satish-Kumar M., Ishikawa Masahiro, Grantham Geoffrey, Sakata Shuhei, Hitara Takafumi
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences Japan Association of Mineralogical Sciences
Event date: 2015
Language:Japanese Presentation type:Other
Ca. 1cm-thick Grt-Hbl vein discordantly cuts a gneissose structure of a Grt-Opx-Hbl gneiss in the central Sor Rondane Mountains, East Antarctica. Changes of mineral compositions and mineral assemblages with a distance from the vein suggest that the Grt-Hbl vein was formed by NaCl-KCl brine infiltration in open system under upper amphibolite facies conditions. Moreover, Zn-, Sr-, Ba-, Pb-, and U-contents in Hbl and Li-, Sr-, Ba-, and Pb-contents in Pl decrease with a distance from the vein. Trace elements compositional profiles with a distance from the vein imply the elements diffuse from the vein to the wall rock.
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Higashino Fumiko, Kawakami Tetsuo, Tsuchiya Noriyoshi, Satish-Kumar M., Ishikawa Masahiro, Grantham Geoffrey H.
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2015
Language:The in addition, foreign language Presentation type:Other
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Yamauchi Koichi, Ishikawa Masahiro, Sato Hiroshi, Iwasaki Takaya, Toyoshima Tsuyoshi
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2015
Language:The in addition, foreign language Presentation type:Other
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Grain growth kinetics in diopside aggregates
Tsubokawa Yumiko, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2015
Language:The in addition, foreign language Presentation type:Other
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Grain growth in diopside agregates
Tsubokawa Yumiko, Ishikawa Masahiro
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences Japan Association of Mineralogical Sciences
Event date: 2015
Language:Japanese Presentation type:Other
Grain growth experiments were performed in sintered polycrystalline diopside. Powders of crushed natural diopside were sintered at temperatures between 1230 - 1280 deg C for 1 - 12h. The grain size increases with increasing time and temperature. At 1230 deg C, we observed normal grain growth characterized by a log-normal grain size distribution following the relation, D<sub>f</sub> <sup>n</sup> ‒ D<sub>0</sub> <sup>n</sup> = kt where n is a constant, D<sub>f</sub> and D<sup>0</sup> are the grain size at time t = t and t = 0 respectively, and k is a rate constant.
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Preliminary experiments on high temperature deformation of polycrystalline diopside
Ishikawa Masahiro, Tsubokawa Yumiko
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences Japan Association of Mineralogical Sciences
Event date: 2015
Language:Japanese Presentation type:Other
Preliminary deformation experiments were carried out on sintered polycrystalline diopside. Creep tests were made in a uniaxial compressional apparatus at temperatures <i>T</i> = 1150 to 1200°C. The specimens were deformed such that strain exceed by 30%.
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Hiroi Yoshikuni, Kobayashi Tomoyuki, Ishikawa Masahiro, Osanai Yasuhito, Nishido Hirotsugu, Motoyoshi Yoichi, Shiraishi Kazuyuki, Kayama Masahiro, Miyake Akira, Adachi Tatsuro, Hokada Tomokazu, Prame Bernard, Satish-Kumar Madhusoodhan, Yanagi Ayahiko, Kato Mutsumi
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2015
Language:The in addition, foreign language Presentation type:Other
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HIGASHINO Fumiko, KAWAKAMI Tetsuo, TSUCHIYA Noriyoshi, SATISH–KUMAR M., ISHIKAWA Masahiro, GRANTHAM Geoffrey H., SAKATA Shuhei, HATTORI Kentaro, HIRATA Takafumi
岩石礦物礦床學 一般社団法人 日本鉱物科学会
Event date: 2015
Language:English Presentation type:Other
The appropriateness of Zr as an 'immobile element' during garnet–hornblende (Grt–Hbl) vein formation potentially caused by the Cl–rich fluid or melt infiltration under upper amphibolite facies condition is examined. The sample used is a Grt–Hbl vein from Brattnipene, Sør Rondane Mountains, East Antarctica that discordantly cuts the gneissose structure of the mafic gneiss.<br/>Modal analysis of the wall rock minerals combined with the quantitative determination of their Zr contents reveals that most of the whole–rock Zr resides in zircon whereas ~ 5% is hosted in garnet and hornblende. The Zr concentration of garnet and hornblende is constant irrespective of the distance from the vein. Zircon shows no resorption or overgrowth microstructures. Moreover, the grain size, chemical zoning (CL, Th/U ratio and REE pattern) and rim ages of zircon are also similar irrespective of the distance from the vein. LA–ICPMS U–Pb dating of zircon rims does not give younger ages than the granulite facies metamorphism reported by previous studies. All of these detailed observations on zircon support that zircon is little dissolved or overgrown, and that Zr is not added nor lost during the Grt–Hbl vein formation. Therefore, Zr can be described as an appropriate 'immobile element' during the Grt–Hbl vein formation. Detailed microstructural observation of zircon is thus useful in evaluating the appropriateness of Zr as an immobile element.
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Sintering of fine-grained polycrystalline diopside
Tsubokawa Yumiko, Ishikawa Masahiro
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences Japan Association of Mineralogical Sciences
Event date: 2014
Language:Japanese Presentation type:Other
This paper investigates a method for preparing the fine-grained polycrystalline diopside via sintering the diopside nanopowder. The diopside (Ca<sub>1</sub>Mg<sub>0.97</sub>Fe<sub>0.03</sub>Si<sub>2</sub>O<sub>6</sub>) single crystal was crushed and milled to particles size of < 1µm. The powders were pressed into cylindrical shape under a uni-axial pressure of 2.0 MPa for 10minutes. The pellets were then sintered at 1130 °C and 1180 °C for 6h and 1230°C, and 1280 °C for 2h and 6h. As a result, polycrystalline diopside with particle size of < 1µm were obtained after sintering at <1230°C. XRD and Raman spectroscopy show that the existence of akermanite (Ca<sub>2</sub>Mg<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>) along with diopside.
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Lithology of Philippine Sea slab under Izu collision zone
Ishikawa Masahiro, Tsubokawa Yumiko, Honda Satoko
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2014
Language:The in addition, foreign language Presentation type:Other
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Higashino Fumiko, Kawakami Tetsuo, Tsuchiya Noriyoshi, Satish-Kumar M, Ishikawa Masahiro, Grantham Geoff
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2014
Language:The in addition, foreign language Presentation type:Other
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Sintering of nanocrystalline labradorite
Honda Satoko, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2014
Language:The in addition, foreign language Presentation type:Other
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Yamauchi Koichi, Ishikawa Masahiro, Toyoshima Tsuyoshi, Sato Hiroshi
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2014
Language:The in addition, foreign language Presentation type:Other
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Mass transfer during highly saline brine activity in the continental collision zone
Higashino Fumiko, Kawakami Tetsuo, Tsuchiya Noriyoshi, Sakata Shuhei, Satish-Kumar M., Ishikawa Masahiro, Grantham Geoff, Hirata Takafumi
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences Japan Association of Mineralogical Sciences
Event date: 2014
Language:Japanese Presentation type:Other
In a Grt-Opx-Hbl gneiss from the central Sor Rondane Mountains, ca. 1cm-thick Grt-Hbl vein discordantly cut the gneissosity. Cl-content of Hbl and Bt, and K-content of Hbl decrease with the distance from the vein center. Sodium-richer rim of Pl gets thinner with a distance from the vein. Therefore, the Grt-Hbl vein was probably formed by NaCl-KCl brine infiltration during early retrograde metamorphic stage. Moreover, Zn-, Sr-, Ba-, Pb- and U-content of Hbl decrease and Nb-, Y- and REE-content of Hbl increase with the distance from the vein center. These elements would have been mobile during the brine activity.
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Tamai Hayata, Muto Jun, Nagahama Hiroyuki, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2013
Language:The in addition, foreign language Presentation type:Other
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Higashino Fumiko, Kawakami Tetsuo, M. Satish-Kumar, Tsuchiya Noriyoshi, Ishikawa Masahiro, Grantham Geoff
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences Japan Association of Mineralogical Sciences
Event date: 2013
Language:Japanese Presentation type:Other
In pelitic gneisses from the eastern Sor Rondane Mountains (SRM), the Cl-rich fluid infiltration took place under ca. 800 <sup>o</sup>C, 0.8 GPa at 600 Ma, near the metamorphic-peak condition. The mineral assemblage in this sample implies that Cl-rich fluid carried LREE and Th away and brought HREE, Zr and Y in. On the other hand, mafic gneisses from the central region preserve the evidence of retrograde Cl-rich fluid activity, where cm-scale veinlet with Cl-rich amphibole cut the penetrative gneissosity discordantly. The Cl-rich fluid activity is distributed linearly for 200km regardless of lithology, and occurred at several stages in the SRM.<br>
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Composition of the northern Izu-Bonin arc crust
Ishikawa Masahiro, Akutagawa Yasuyuki, Katsune Go, Tsutsumi Daisuke
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2013
Language:The in addition, foreign language Presentation type:Other
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Tsuchiya Noriyoshi, Ishikawa Masahiro, Satish-Kumar Madhusoodhan, Kawakami Tetsuo, Kojima Hideyasu, Kaiden Hiroshi, Hideki Miura, Suganuma Yusuke, Abe Mikio, Sasaki Daisuke, Chiba Masanori, Okada Yutaka, Hashizume Fumio, Grantham Goeff, Goderis Steven
Antarctic record National Institute of Polar Research
Event date: 2012.11
Language:Japanese Presentation type:Other
Earth science-related field activities, involving geology, geomorphology and meteorite searches, were carried out in the Sor Rondane Mountains, Eastern Dronning Maud Land, during the 2009-2010 summer season as a part of the 51st Japanese Antarctic Research Expedition (JARE-51), in collaboration with the Belgian Antarctic Research Expedition (BELARE). Geology and geomorphology parties accessed the Sor Rondane Mountains using the Dronning Maud Land Air Network (DROMLAN), and the meteoritesearch party to Antarctica on the maiden voyage by the new Japanese icebreaker Shirase. The geology party covered the entire area of the Sor Rondane Mountains, although with an emphasis on the eastern part. The geomorphology party carried out fieldwork in western and central parts of the mountains, and the meteorite search party performed a survey in the eastern part. All field activities were succes fully carried out. Some of the geology members returned to Japan by DROMLAN, while others flew to Syowa Station from the Sor Rondane Mountains by DROMLAN, and then returned to Japan on board Shirase. This report provides a summary of the field operations, including logistics and weather records.
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Extensional and strike-slip tectonics in the eastern Sør Rondane Mountains, Antarctica
Ishikawa Masahiro, Kawakami Tetsuo, Kumar Satish-, Tsuchiya Noriyoshi, Grantham Geoff
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences Japan Association of Mineralogical Sciences
Event date: 2012
Language:Japanese Presentation type:Other
In order to provide structural constraints to better understand how the East-African- Antarctic-Orogen was deformed during continental collision of East Gondwanaland and West Gondwanaland, some authors have performed a geological survey in the Balchenfjella of the eastern Sør Rondane Mountains, east Dronning Maud Land, East Antarctica. Results of new field mapping shows that the metamorphic rocks of the Balchenfjella can be structurally divided into two units named Gropeheia unit and Berrheia unit, which are separated by large scale ductile shear zone.
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Granite and serpentinite adjacent to plate boundary of NE Honshu arc
Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2012
Language:The in addition, foreign language Presentation type:Other
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Felsite inclusions in granulites from continental collision orogens: Their tectonic significance
Hiroi Yoshikuni, Shiraishi K, Yanagi A, Kato M, Kobayashi T, Prame B., Ishikawa M, Satish-Kumar M, Hokada T, Motoyoshi Y
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2012
Language:The in addition, foreign language Presentation type:Other
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Timing of chlorine-rich fluid infiltration and behavior of REE-bearing minerals in high-temperature metamorphic terrane
Higashino Fumiko, Kawakami Tetsuo, Satish-Kumar M, Tsuchiya Noriyoshi, Ishikawa Masahiro, Grantham Geoff
Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences 2012 Japan Association of Mineralogical Sciences
Event date: 2012
Language:Japanese Presentation type:Other
Pelitic gneisses with Cl-rich biotite included in garnet are linearly distributed for 200 km long in the Sor Rondane Mountains. The condition of Cl-rich fluid infiltration is estimated to be ca. 800 oC, 8 kbar at 600 Ma. Garnet in this sample has core-rim boundary defined by P-zoning, rim formation being contemporaneous with the Cl-rich fluid infiltration. The garnet core includes monazite, and the rim includes xenotime and coarse-grained zircon. This suggests that originally LREE-rich mineral assemblage changed to HREE- and Zr-rich ones, because of Cl-rich fluid infiltration. Further study is needed to account for the mechanism of this process.
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HIROI Yoshikuni, YANAGI Ayahiko, KATO Mutsumi, KOBAYASHI Tomoyuki, HOKADA Tomokazu, MOTOYOSHI Yoichi, SHIRAISHI Kazuyuki, ISHIKAWA Masahiro, Satish-Kumar M
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2011
Language:Japanese Presentation type:Other
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SATISH-KUMAR M., TSUCHIYA N., KAWAKAMI T., ISHIKAWA M.
日本鉱物科学会年会講演要旨集
Event date: 2010.9
Language:English Presentation type:Other
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Lithostructure of the oceanic crust based on the Seismic velocities of rocks in the Oman ophiolite
SAITO S., ISHIKAWA M., SHIBATA S., AKIZUKI R., ARIMA M., TATSUMI Y., ARAI S.
Event date: 2010.9
Language:Japanese Presentation type:Other
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南極リュツォ・ホルム岩体下の含黒雲母下部地殻:下部地殻の交代作用?
石川 正弘
日本鉱物科学会年会 日本鉱物科学会
Event date: 2010
Language:Japanese Presentation type:Oral presentation (general)
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Shibata Satoshi, Saito Satoshi, Ishikawa Masahiro, Arai Shoji
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2010
Language:Japanese Presentation type:Other
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Kato Naoko, Saito Hideo, Abe Susumu, Kodaira Shuichi, Takahashi Narumi, Sato Takeshi, Sato Hiroshi, Ishiyama Tatsuya, Kurashimo Eiji, Koshiya Shin, Yoshida Takeyoshi, Toyoshima Tsuyoshi, Ishikawa Masahiro, Toda Shigeru
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2010
Language:Japanese Presentation type:Other
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Al2SiO5 minerals in the pelitic metamorphic rocks from Sør Rondane Mountains, East Antarctica
Kawakami Tetsuo, Ishikawa Masahiro, Satish Kumar, Tsuchiya Noriyoshi, Yoshida Kenta
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2010
Language:Japanese Presentation type:Other
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Hydrothermal alteration in the Tanzawa Group
Kume Hiroyuki, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2010
Language:Japanese Presentation type:Other
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Siderite bearing granulite from Zazafotsy,Madagascar
Hokazono Yuichi, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2010
Language:Japanese Presentation type:Other
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Tsutsumi Daisuke, Ishikawa Masahiro, Arima Makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2010
Language:Japanese Presentation type:Other
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Seismic velocities of rocks in the Oman Ophiolite
Saito Satoshi, Ishikawa Masahiro, Shibata Satoshi, Akizuki Ryunosuke, Arima Makoto, Tatsumi Yoshiyuki, Arai Shoji
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2010
Language:Japanese Presentation type:Other
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Akizuki Ryunosuke, Saito Satoshi, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2010
Language:Japanese Presentation type:Other
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Saito Satoshi, Ishikawa Masahiro, Arima Makoto, Tatsumi Yoshiyuki
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2009
Language:Japanese Presentation type:Other
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ISHIKAWA MASAHIRO
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2009
Language:Japanese Presentation type:Other
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O-138 Elastic wave velocities of plagioclase as functions of temperature and composition
Kono Yoshio, Miyake Akira, Ishikawa Masahiro, Arima Makoto
The Geological Society of Japan
Event date: 2008.9
Language:Japanese Presentation type:Other
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Matsumoto Yuki, Ishikawa Masahiro, Arima Makoto
The Geological Society of Japan
Event date: 2008.9
Language:Japanese Presentation type:Other
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ISHIKAWA Masahiro, SASAKI Satoko
The Geological Society of Japan
Event date: 2008.9
Language:Japanese Presentation type:Other
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ISHIKAWA Masahiro, SASAKI Satoko
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2008
Language:Japanese Presentation type:Other
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Matsumoto Yuki, Ishikawa Masahiro, Arima Makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2008
Language:Japanese Presentation type:Other
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Elastic wave velocities of plagioclase as functions of temperature and composition
Kono Yoshio, Miyake Akira, Ishikawa Masahiro, Arima Makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2008
Language:Japanese Presentation type:Other
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Temperature derivatives of elastic wave velocities in plagioclase(An51±1)above and below the order-disorder transition temperature
石川 正弘, 有馬 眞
American Mineralogist 93 2008
Event date: 2008
Language:The in addition, foreign language Presentation type:Other
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P-128 Fluid inclusions in the Tanzawa plutonic complex
SASAKI Satoko, ISHIKAWA Masahiro
The Geological Society of Japan
Event date: 2007.9
Language:Japanese Presentation type:Other
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S-61 Effect of E_2O fluid on elastic wave velocity of rocks at high pressure and temperatures
ISHIKAWA MASAHIRO, MATSUMOTO YUKI, ARIMA MAKOTO
The Geological Society of Japan
Event date: 2007.9
Language:Japanese Presentation type:Other
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ISHIKAWA MASAHIRO, ARIMA MAKOTO
The Geological Society of Japan
Event date: 2007.9
Language:Japanese Presentation type:Other
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KATSUNE GO, ISHIKAWA MASAHIRO, ARIMA MAKOTO
The Geological Society of Japan
Event date: 2007.9
Language:Japanese Presentation type:Other
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P-96 Effect of melting reaction on elastic wave velocities and Poisson's ratio of amphibolites
Kojo Shihoko, Arima Makoto, Ishikawa Masahiro
The Geological Society of Japan
Event date: 2007.9
Language:Japanese Presentation type:Other
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P-162 P-T structure of the Lutzow-Holm Complex, East Antarctica
Ichiki Takashi, Ishikawa Masahiro
The Geological Society of Japan
Event date: 2007.9
Language:Japanese Presentation type:Other
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Effect of H2O fluid on elastic wave velocity of rocks at high pressure and temperatures
ISHIKAWA MASAHIRO, MATSUMOTO YUKI, ARIMA MAKOTO
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2007
Language:Japanese Presentation type:Other
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Effect of melting reaction on elastic wave velocities and Poisson's ratio of amphibolites
KOJO SHIHOKO, ARIMA MAKOTO, ISHIKAWA MASAHIRO
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2007
Language:Japanese Presentation type:Other
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ISHIKAWA MASAHIRO, ARIMA MAKOTO
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2007
Language:Japanese Presentation type:Other
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P-T structure of the Lützow-Holm Complex, East Antarctica
Ichiki Takashi, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2007
Language:Japanese Presentation type:Other
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Tectonics of the Horoman area in the southern part of Hidaka collision belt, Hokkaido, Japan.
Yamamoto Hiroshi, Nakamori Natsumi, Ishikawa Masahiro, Terabayashi Masaru, Kaneko Yoshiyuki, Rehman Hafiz Ur
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2007
Language:Japanese Presentation type:Other
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Fluid inclusions in the Tanzawa plutonic complex
SASAKI Satoko, ISHIKAWA Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2007
Language:Japanese Presentation type:Other
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katsune go, ishikawa masahiro, arima makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2007
Language:Japanese Presentation type:Other
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Fujimoto Yoshikazu, Kono Yoshio, Ishikawa Masahiro, Hirajima Takao, Arima Makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2006
Language:Japanese Presentation type:Other
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Soil N dynamics in a forest ecosystem in West Tanzawa:Substrate, landslide and vegetation
Kaneko Nobuhiro, Fujimaki Reiji, Ishikawa Masahiro, Sakai Akiko, Tomita Mizuki, Kawasaki Akiyuki
The Japanese Forest Society Congress THE JAPANESE FORESTRY SOCIETY
Event date: 2006
Language:The in addition, foreign language Presentation type:Other
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The correlations of geospheric activities using GIS analysis in northeast Japan
NISHIMOTO Soushi, ISHIKAWA Masahiro
Event date: 2005.9
Language:Japanese Presentation type:Other
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Slope failures triggered by Kanto earthquake
ISHIKAWA Masahiro, KOMITO Yuta, NISHIMOTO Soushi
Event date: 2005.9
Language:Japanese Presentation type:Other
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AZUMA T., OTA Y., ISHIKAWA M., TANIGUCHI K.
The Quaternary Research (Daiyonki-Kenkyu) Japan Association for Quaternary Research
Event date: 2005.6
Language:Japanese Presentation type:Other
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NISHIMOTO Soushi, ISHIKAWA Masahiro, ARIMA Makoto, YOSHIDA Takeyoshi
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2005
Language:Japanese Presentation type:Other
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Subduction of anhydrous slab and its implication for seismotectonics in the Kanto area
ISHIKAWA Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2005
Language:Japanese Presentation type:Other
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Low velocity anomaly resulting from structural transformation of intermediate plagioclase
Kono Yoshio, Ishikawa Masahiro, Arima Makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2005
Language:Japanese Presentation type:Other
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Slab tear beneath the Tanzawa Mountain and seismotectonics of the Izu collision zone
Ishikawa Masahiro
Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists Japan Association of Mineralogical Sciences
Event date: 2005
Language:Japanese Presentation type:Other
The plate boundary fault between Philippine Sea plate and Honshu plate is the source of the Kanto earthquake of 1923 in the central Japan. It is important to identify the geometry of the plate boundary. In this study, a N-S trending tear of the seismogenic zone was identified beneath the Tanzawa Mountain with three dimensional GIS analysis for earthquake data. This is a slab tear of the subducted lower crust of the Izu arc which is the uppermost layer of Philippine Sea slab. The Philippine Sea slab beneath the western half of the Tanzawa Mountain is much deeper than the slab depth beneath the eastern half of the Tanzawa Mountain. The position of the slab tear shows a spatial link to the predicted western margin of the earthquake source fault of the Kanto earthquake of 1923. The identified complex geometry of the plate boundary can be used to predict hazardous earthquakes of the Tokyo metropolitan region.
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Matsumoto Yuki, Kono Yoshio, Terabayashi Masaru, Ishikawa Masahiro, Arima Makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2005
Language:Japanese Presentation type:Other
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Ultrasonic P and S wave velocity measurements at mid-to-lower crustal conditions of pressure and temperature in a piston cylinder apparatus.
石川 正弘
Proceedings of the 1st workshop on IODP physical property measurement. 2005
Event date: 2005
Language:The in addition, foreign language Presentation type:Other
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Digital Mapping of Geosphere Information in the Tanzawa Mountains using GIS
ISHIKAWA Masahiro, FUJII Gen-ya
Event date: 2004.9
Language:Japanese Presentation type:Other
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GIS analysis for geodynamics in NE Japan
NISHIMOTO Soushi, ISHIKAWA Masahiro
Event date: 2004.9
Language:Japanese Presentation type:Other
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O-140 P-wave velocities of 'dry' and 'wet' wehrlite up to 1000℃ at 1Gpa
Kono Y, Ishikawa M, Arima M
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2004
Language:Japanese Presentation type:Other
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P-163 Digital Structural Model of Madagascar using GIS and DEM
ISHIKAWA Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2004
Language:Japanese Presentation type:Other
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NISHIMOTO Soushi, ISHIKAWA Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2004
Language:Japanese Presentation type:Other
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P-13 Shear sense analysis of Tanzawa Metamorphic Complex
Tayama Ryoichi, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2004
Language:Japanese Presentation type:Other
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KITAMURA K, KANAGAWA K, ISHIKAWA M, ARIMA M, SHIRAISHI S
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2004
Language:Japanese Presentation type:Other
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Kono Y., Ishikawa M., Nakajima T., Khan Said Rahim, Arima M.
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2003
Language:Japanese Presentation type:Other
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Nishimoto Soushi, Ishikawa Masahiro, Arima Makoto, Yoshida Takeyoshi
Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists Japan Association of Mineralogical Sciences
Event date: 2003
Language:The in addition, foreign language Presentation type:Other
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Ishikawa Masahiro, Yamamura Hirokazu, Tayama Ryoichi
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2003
Language:Japanese Presentation type:Other
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High P-T measurements of Vpin ultrabasic Ichino-megata xenoliths, NE Japan
NISHIMOTO Soushi, ISHIKAWA Masahiro, ARIMA Makoto, YOSHIDA Takeyoshi
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2003
Language:Japanese Presentation type:Other
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Ductile deformation and metamorphic evolution of Tanzawa Metamorphic Complex
Tayama Ryoichi, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2003
Language:Japanese Presentation type:Other
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The relationship between metamorphic grade and rock velocity in high grade metamorphic rock
KITAMURA Keigo, ISHIKAWA Masahiro, ARIMA Makoto, Shiraishi Kazuyuki
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2003
Language:Japanese Presentation type:Other
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O-270 非剛体プレートテクトニクス : 顕生代以降の最上部マントルの脆弱化(21. テクトニクス(液晶有),口頭発表,一般講演)
石川 正弘
日本地質学会学術大会講演要旨 一般社団法人 日本地質学会
Event date: 2002
Language:English Presentation type:Other
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High pressure and high temperature P-wave velocity measurement in ultrabasic Ichino-megata xenoliths
NISHIMOTO Soushi, ISHIKAWA Masahiro, ARIMA Makoto, YOSHIDA Takeyoshi
Abstracts of Papers Presented at the Annual Meeting of The Japanese Association of Mineralogists, Petrologists and Economic Geologists Japan Association of Mineralogical Sciences
Event date: 2002
Language:The in addition, foreign language Presentation type:Other
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Ishikawa Masahiro, Kanao Masaki
Bulletin of the Earthquake Research Institute, University of Tokyo The University of Tokyo
Event date: 2002
Language:Japanese Presentation type:Other
A combination of rock velocities with seismic structures have presented clues to understanding the structure and the evolution of the continental crust. However, most works addressed continental crusts of the northern hemisphere such as North America and Europe. Only a few studies focused on Gondwanaland. Here, we present a tectonic model of the Pan-African orogeny by comparing the laboratory velocities of granulite/gneiss with geophysical data of the Lutzow-Holm region, East Antarctica. The ""Structure and Evolution of the East Antarctic Lithosphere (SEAL)"" project has been carried out under the framework of the Japanese Antarctic Research Expedition in recent years. Several geophysical studies including deep seismic refraction/wide angle reflection surveys have been conducted at the Lutzow-Holm region. Velocity models and reflection sections of the crust are given by both active source seismic surveys and passive analyses for teleseismic receiver functions. From laboratory measurements, rock velocities revealed that the lower crust (6.9 km/s) consists of pyroxene granulite. Moreover, middle crustal velocity is equivalent to the velocity of mixture of pyroxene granulite (20%) and felsic gneiss (80%). The ratio of pyroxene granulite is similar to that geologically observed as meta-mafic sills, which were probably related to mafic magma underplating at Archean. The idea is also supported by model calculations of acoustic impedance, which show middle and lower crustal laminations. This evidence demonstrates that the East Gondwanaland (Napier Complex) lies under the Pan-African orogenic belt (Lutzow-Holm Complex) and was subducted westward. Because it is pointed out that West Gondwanaland descended eastward under the Pan-African belt, the coalescence of both Gondwanalands, i.e. formation process of Gondwana supercontinent is regarded as collision tectonics along with symmetrical subductions where late Proterozoic island arcs and ophiolites were put between East Gondwanaland and West Gondwanaland. The lithospheric structure of the Pan-African belt will be clarified by making deep seismic surveys to cross over the continental segments in the southern hemisphere that once were fragments of Gondwanaland. Deep seismic profiling in the LEGENDS (Lithospheric Evolution of Gondwana East iNterdisciplinary Deep Surveys) project will reveal the architecture and the evolution of the lithosphere of these regions. The ""SEAL"" transect has also been carried out as the chief contribution to LEGENDS, to delineate a whole crustal section in different geological terrains from Western Enderby Land to Eastern Dronning Maud Land, East Antarctica.
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P-154 Elastic wave velocity measurement at 1.0 GPa and up to 1000℃
Kono Yoshio, Ishikawa Masahiro, Arima Makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2002
Language:Japanese Presentation type:Other
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P-132 The correlation between rock velocity anisotropy and micro-fabrics under high P-T condition
KITAMURA Keigo, ISHIKAWA Masahiro, ARIMA Makoto, Shiraishi Kazuyuki
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2002
Language:Japanese Presentation type:Other
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Ishikawa Masahiro, Kanao Masaki
Bulletin of the Earthquake Research Institute,University of Tokyo The University of Tokyo
Event date: 2002
Language:Japanese Presentation type:Other
A combination of rock velocities with seismic structures have presented clues to understanding the structure and the evolution of the continental crust. However, most works addressed continental crusts of the northern hemisphere such as North America and Europe. Only a few studies focused on Gondwanaland. Here, we present a tectonic model of the Pan-African orogeny by comparing the laboratory velocities of granulite/gneiss with geophysical data of the Lutzow-Holm region, East Antarctica. The ""Structure and Evolution of the East Antarctic Lithosphere (SEAL)"" project has been carried out under the framework of the Japanese Antarctic Research Expedition in recent years. Several geophysical studies including deep seismic refraction/wide angle reflection surveys have been conducted at the Lutzow-Holm region. Velocity models and reflection sections of the crust are given by both active source seismic surveys and passive analyses for teleseismic receiver functions. From laboratory measurements, rock velocities revealed that the lower crust (6.9 km/s) consists of pyroxene granulite. Moreover, middle crustal velocity is equivalent to the velocity of mixture of pyroxene granulite (20%) and felsic gneiss (80%). The ratio of pyroxene granulite is similar to that geologically observed as meta-mafic sills, which were probably related to mafic magma underplating at Archean. The idea is also supported by model calculations of acoustic impedance, which show middle and lower crustal laminations. This evidence demonstrates that the East Gondwanaland (Napier Complex) lies under the Pan-African orogenic belt (Lutzow-Holm Complex) and was subducted westward. Because it is pointed out that West Gondwanaland descended eastward under the Pan-African belt, the coalescence of both Gondwanalands, i.e. formation process of Gondwana supercontinent is regarded as collision tectonics along with symmetrical subductions where late Proterozoic island arcs and ophiolites were put between East Gondwanaland and West Gondwanaland. The lithospheric structure of the Pan-African belt will be clarified by making deep seismic surveys to cross over the continental segments in the southern hemisphere that once were fragments of Gondwanaland. Deep seismic profiling in the LEGENDS (Lithospheric Evolution of Gondwana East iNterdisciplinary Deep Surveys) project will reveal the architecture and the evolution of the lithosphere of these regions. The ""SEAL"" transect has also been carried out as the chief contribution to LEGENDS, to delineate a whole crustal section in different geological terrains from Western Enderby Land to Eastern Dronning Maud Land, East Antarctica.
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Kitamura Keigo, Ishikawa Masahiro, Arima Makoto, Shiraishi Kazuyuki
Polar geoscience 国立極地研究所
Event date: 2001.10
Language:English Presentation type:Other
P-wave velocities (Vp) were measured for nine samples of granulite facies metamorphic rock from the early Paleozoic Liitzow-Holm Complex, East Antarctica. The measurements were done at pressures from 0.1 Gpa to 1.0 Gpa and at temperatures from 25℃ to 400℃ with a piston-cylinder apparatus. Vp values of the ultrabasic-basic granulites range from 6.65 to 7.29 km/s at 1.0 Gpa and 25℃. The felsic gneiss shows nearly constant Vp value from 25℃ to 400℃ at 0.6 and 1.0 Gpa, whereas it exhibits rapid decrease of Vp with increasing temperature at 0.4Gpa. In all rock samples measured, the biotite-two pyroxene granulite shows the strongest negative thermal effect of Vp (0.45 km/s). This strong thermal effect is attributed to relatively higher biotite abundance.
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Kouno Yoshio, Ishikawa Masahiro, Arima Makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2001
Language:Japanese Presentation type:Other
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KITAMURA Keigo, ISHIKAWA Masahiro, ARIMA Makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2001
Language:Japanese Presentation type:Other
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Geology of the Kokchetav UHP-HP metamorphic belt, Northern Kazakhstan
KANEKO Y., MARUYAMA S., TERABAYASHI M., YAMAMOTO H., ISHIKAWA M., ANMA R., PARKINSON C. D., OTA T., NAKAJIMA Y., KATAYAMA I., YAMAMOTO J., YAMAUCHI K.
The Island arc
Event date: 2000.9
Language:English Presentation type:Other
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YAMAMOTO HIROSHI, ISHIKAWA MASAHIRO, ANMA RYO, KANEKO YOSHIYUKI
The Island arc
Event date: 2000.9
Language:English Presentation type:Other
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P-178 Ductile shear in the Tanzawa metamorphic rocks and arc-arc collision tectonics
MANO Kensaku, ISHIKAWA Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2000
Language:Japanese Presentation type:Other
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P-181 P-wave velocity in lower crustal rocks of Kohistan arc
KOUNO Yoshio, ISHIKAWA Masahiro, ARIMA Makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2000
Language:Japanese Presentation type:Other
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Nishimoto S., Ishikawa M., Arima M., Yoshida T.
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2000
Language:Japanese Presentation type:Other
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P-179 Seismic velocities in deep crustal rocks and crustal structures of island arcs
ISHIKAWA M., KITAMURA K., NISHIMOTO S., TANABE Y., KOUNO Y., ARIMA M.
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 2000
Language:Japanese Presentation type:Other
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SUZUKI S., Hokada Tomokazu, Ishikawa Masahiro, Ishizuka Hideo
Polar Geoscience 国立極地研究所
Event date: 1999
Language:English Presentation type:Other
The Mt. Riiser-Larsen area of the Napier Complex, East Antarctica, is underlain by various kinds of ultrahigh-temperature (UHT) metamorphic rocks such as orthopyroxene felsic gneiss, garnet felsic gneiss, garnet-sillimanite gneiss, mafic gneiss and meta-ultramafic rocks. On the basis of the mode of occurrence and petrography, the garnet felsic gneisses are further divided into garnet felsic gneiss I (garnet-poor type) and II (garnet-rich type), the mafic gneisses into quartz-free and -bearing types, and the metaultramafic rocks into phlogopite-free and -bearing types. Bulk rock chemical analyses for the major, minor and rare earth elements (REEs) demonstrate that (1) both the garnetsillimanite gneiss and garnet felsic gneiss II are of sedimentary origin such as mudstone and sandstone, respectively, and (2) other rocks are of igneous origin, as follows: i) the orthopyroxene felsic gneiss and garnet felsic gneiss I are chemically comparable with CIPW normative tonalite to granodiorite and granite, respectively, of which the former also exhibits a calc-alkaline compositional variation with a REE signature comparable to the Archaean TTG (tonalite-trondhjemite-granodiorite); ii) the quartz-free and quartz-bearing mafic gneisses have been derived from flat or slightly LREE-depleted and LREE-enriched tholeiitic basalts, respectively; iii) phlogopite-free and phlogopite-bearing meta-ultramafic rocks have been derived from depleted mantle peridotites and komatiitic rocks, respectively, of which the latter shows a magmatic compositional variation controlled by addition or subtraction of only olivine. These chemical features reveal that the various kinds of original rocks are intermingled in the Riiser-Larsen area, which is important for understanding the site of development of original rocks in the Napier Complex.
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Elastic wave velocities in Izu-Ogasawara island arc rocks to pressure of 1.0 GPa
Kitamura Keigo, Ishikawa Masahiro, Arima Makoto
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 1999
Language:Japanese Presentation type:Other
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Elastic wave velocities and composition of island arc crustal rocks
ISHIKAWA Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 1999
Language:Japanese Presentation type:Other
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Geology of the Mt. Riiser-Larsen area of the Napier Complex, Enderby Land, East Antarctica
ISHIZUKA H., Ishikawa Masahiro, Hokada Tomokazu, Suzuki Satoko
Polar Geoscience 国立極地研究所
Event date: 1998
Language:English Presentation type:Other
The summer party of the 38th Japanese Antarctic Research Expedition (1996-97) performed field work in the Mt. Riiser-Larsen area of the Archaean Napier Complex, Enderby Land, East Antarctica. The area is underlain by various kinds of metamorphic rocks and unmetamorphosed intrusive rocks. Of these, the metamorphic rocks are tentatively divided into the layered gneiss series, massive gneiss series, and transitional gneiss series. The layered gneiss series, occurring in the central to northwestern part of the area, is characterized by layering structure composed of several types of garnet felsic gneiss with subordinate amounts of orthopyroxene felsic gneiss, pelitic and mafic gneisses, impure quartzite, and metamorphosed banded iron formation. The massive gneiss series is predominant in the southern to southeastern part and consists mainly of massive orthopyroxene felsic gneiss, in which the layering structure is not conspicuous and the lithology is rather monotonous. The transitional gneiss series is developed between the layered and massive gneiss series, in which metamorphosed anorthosite and ultramafic rocks occur characteristically as thin layers or blocks or pods. Metamorphic foliation, which is almost always parallel to the layering structure, strikes NE-SW to E-W and dips at moderate to gentle angles (20-40°) to the south or southeast. The mineral associations indicate that the majority of the metamorphic rocks could belong to the high temperature granulite facies at metamorphic temperature higher than 1000℃. Unmetamorphosed doleritic intrusive rocks, so-called Amundsen Dikes, intrude throughout the area, striking N-S and NE-SW. Furthermore, there are many shear zones, following preexisting structures such as dike margins, in which the gneisses and dikes have been sheared to mylonites or pseudotachylite-like rocks.
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Assembly and dispersion of super continents and continental delamination
Arima Makoto, Ishikawa Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 1998
Language:Japanese Presentation type:Other
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Seismic structures and dynamics of continental crusts
ISHIKAWA Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 1998
Language:Japanese Presentation type:Other
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Ishizuka Hideo, Miura Hideki, Takada Masashi, Ishikawa Masahiro, Zwartz Daniel Peter, Suzuki Satoko, Hokada Tomokazu
Antarctic record National Institute of Polar Research
Event date: 1997.11
Language:Japanese Presentation type:Other
The 38th Japanese Antarctic Research Expedition (JARE-38) performed field work on geology and geomorphology in the Mt. Riiser-Larsen area, Enderby Land, for 65 days from December 16,1996 to February 18,1997. This was a first-year activity of the SEAL (Structure and Evolution of East Antarctic Lithosphere) project. The field work was conducted by two groups, one consisting of four geologists and the other of three geomorphologists. Each group carried out the geological and geomorphological surveys, respectively, and collected scientific samples totaling about 3500kg. This report gives details of the plan and actual logistics, and also summarizes the preliminary results of the field work.
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The Napier Complex in East Antarctica-The oldest carton and the ultra-high-temperature metamorphism
ISHIZUKA Hideo, ISIKAWA Masahiro, SUZUKI Satoko, HOKADA Tomokazu
The Journal of the Geological Society of Japan The Geological Society of Japan
Event date: 1997.9
Language:Japanese Presentation type:Other
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177 Structures of the Mt.Riiser-Larsen area in the Napier Complex,East Antarctica
Ishikawa Masahiro, Hokada Tomokazu, Suzuki Satoko, Ishizuka Hideo
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 1997
Language:Japanese Presentation type:Other
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440 High-strain-rate shear zones in Lutzow-Holm Complex, Antarctica
ISHIKAWA Masahiro
Annual Meeting of the Geological Society of Japan The Geological Society of Japan
Event date: 1996
Language:Japanese Presentation type:Other
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GEOCHRONOLOGICAL CONSTRAINTS ON THE METAMORPHIC EVOLUTION AT RUNDVAGSHETTA, EAST ANTARCTICA
FRASER Geoffrey L., WILLIAMS Ian S., ISHIKAWA Masahiro, MOTOYOSHI Yoichi, SHIMURA Toshiaki, TSUCHIYA Noriyoshi, ELLIS David J.
Proceedings of the NIPR Symposium on Antarctic Geosciences 国立極地研究所
Event date: 1995.9
Language:English Presentation type:Other
The highest grade rocks in the Lutzow-Holm Complex of East Antarctica are exposed at Rundvagshetta, where peak pressures and temperatures are estimated to have reached ∿10kbar, >900℃ (Y. MOTOYOSHI et al.; The 13th Symposium on Antarctic Geosciences, Programme and Abstracts, Tokyo, Natl Inst. Polar Res., 62,1993). K. SHIRAISHI et al. (J. Geol., 102,47,1994) report U/Pb SHRIMP zircon analyses from a garnet-biotite gneiss. Late Archaean-early Proterozoic ages from zircon cores were interpreted as detrital sedimentary ages, while rim overgrowths with a mean age of 521±9Ma were regarded as the time of peak metamorphism. Further SHRIMP zircon analyses (this study) lend support to this interpretation, but provide additional information. Zircon separates from two metapelitic rocks (sample numbers R-125 and R-12) have been analysed. Both samples contain a primary metamorphic assemblage of garnet+sillimanite+orthopyroxene with secondary cordierite forming at the expense of garnet. Sample R-12 also shows cordierite+sapphirine+spinel symplectites around sillimanite. All zircon grains were imaged by cathodoluminescence prior to ion probe analysis, revealing the presence of growth zones with distinct chemistry. Zircons from R-125 fall into two groups based on internal structure. Type I zircons contain cores which are often broken or corroded. These cores yield late Archaean-early Proterozoic ages and are best interpreted as sedimentary detrital zircon. Overgrowing these cores is a euhedral zone, characterised by high U contents (>1000ppm) and very low Th/U ratios (<0.03). This generation of overgrowth, of probable metamorphic origin, yields a late-Proterozoic age, and has not been distinguished in previous work. A second generation of metamorphic overgrowth forms around the high U band. This second generation zircon has much higher Th/U (typically between 0.5 and 1.0), U contents between 100 and 250ppm, and is comparable in age to the zircon rims dated by K. SHIRAISHI et al. (J. Geol., 102,47,1994). Many grains also show a further narrow rim of zircon which is generally too narrow to analyse, and cannot be distinguished in age from the second generation overgrowths. The second type of zircon in R-125 forms equant, homogeneous grains, often with sector zoning. The chemistry (Th/U and U content) and age of these grains is indistinguishable from the second generation overgrowths in type I zircons. Sample R-12,despite being a similar rock composition to R-125,shows a very different, and much simpler zircon population. All zircons analysed from R-12 are unstructured, unzoned and form a single late Proterozoic-early Cambrian age population, corresponding to the second generation overgrowths in R-125. These grains have a low U content (typically ∿50ppm) and Th/U in the range 0.25-0.5. No detrital cores have been recognized in zircons from R-12. Several questions are raised by these results; 1) why does R-12 lack detrital zircon, and fail to show evidence of the early stage of metamorphic zircon growth seen in R-125? 2) do the two phases of metamorphic zircon growth seen in R-125 represent two distinct thermal/metamorphic events, or 3) are they the result of a single, prolonged P-T cycle, during which zircon growth is episodic and controlled by subtle changes in local chemistry (possibly the result of contemporaneous reactions amongst primary metamorphic assemblages). Answering these questions is central to the interpretation of zircon ages in all high-grade terrains and the subject of ongoing work. Despite the current uncertainty in interpretation of the results presented above, the conclusion that high-grade metamorphic conditions prevailed at Rundvagshetta at around 550Ma is inescapable. When considered in combination with K/Ar and ^<40>Ar/^<39>Ar ages (see G. F. FRASER and McDOUGALL; Proc. NIPR Symp. Antarct. Geosci., 8,137,1995), this age allows us to constrain the rate of cooling following high-grade metamorphism. Biotite from a biotite gneiss at Rundvagshetta yields a K/Ar age of 516±5Ma, and a ^<40>Ar/^<39>Ar age spectrum suggestive of gradual closure to argon diffusion over the period from 525-500Ma. These results suggest that the region cooled below ∿300℃ (closure temperature for argon in biotite) by about 516Ma. Assuming a temperature of ∿900℃ (as estimated by Y. MOTOYOSHI et al. (The 13th Symposium on Antarctic Geosciences, Programme and Abstracts, Tokyo, Natl Inst. Polar Res., 62,1993) for the period of zircon growth at ∿550Ma, the biotite cooling age would suggest an average colling rate of ∿15℃/Ma. For realistic geothermal gradients, cooling of the terrain to <300℃requires considerable uplift from peak metamorphic pressures of ∿10kbars. For example, assuming an upper crustal gradient of 30℃/km implies a maximum pressure constraint of 3-4kbars at ∿516Ma. However, it is not yet clear whether the ∿550Ma period of zircon growth represents peak pressure conditions, or some stage during the decompression history, therefore it is not possible to confidently constrain the rate of exhumation.