著者

磯崎 行雄 丸山 茂徳 中間 隆晃 山本 伸次 柳井 修一

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.120, no.1, pp.65-99, 2011-02-25 (Released:2011-05-20)

参考文献数

80

被引用文献数

32 48

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The ca. 700 million year-long geotectonic history of the Japanese Islands comprises three distinct intervals; i.e., (1) the age of a passive continental margin off the South China continental margin (ca. 700-520 Ma), (2) the age of an active margin characterized by an arc-trench system (ca. 520-20 Ma), and (3) the age of an island arc off East Asia (20 Ma to the present). These three intervals are chronologically separated by two major boundaries with significant tectonic episodes; i.e., the ca. 520 Ma tectonic inversion from a passive to an active margin by the initiation of subduction from the Pacific side, and the ca. 20 Ma tectonic isolation of the modern island arc system from the Asian margin by the back-arc basin (Japan Sea) opening. Here, the evolutionary history of the Japanese Islands is revised significantly on the basis of new lines of information that derived from a new dating technique of detrital zircon in sandstone. Particularly noteworthy is the recognition of the Early Paleozoic to Middle Mesozoic arc batholiths that were exposed extensively in the past but not at all at present because the pre-Cretaceous granites merely occur as kilometer-size blocks in the modern Japanese Islands. As to these older granites, the remarkable disagreement between the current distribution and the predominance of their clastic grains in younger sandstones suggests the effectiveness of past tectonic erosion processes in the fore-arc domains. The newly documented historical change in sandstone provenance suggests that proto-Japan has experienced not only accretionary growth but also large-scale tectonic erosion in multiple stages. During the ca. 500 million-year history of the Japanese Islands, a large amount of juvenile arc (continental) crust was formed several times, however, most has already disappeared from the Earth's surface. In short, the orogenic growth of Japan, even in a long-lasting active continental margin setting, is explained as the intermittent repetition of ocean-ward continental growth and continent-ward contraction of an active arc-trench system. In contrast to these arc batholiths, the terrigenous flux from the neighboring two major continental blocks (South and North China) was less significant than previously imagined, except for the Jurassic to Early Cretaceous time when the collisional suture between North and South China blocks was selectively eroded to produce abundant terrigenous clastics. It is also significant that the eastern extension of this collisional suture was recognized in Japan as a chain of fragmentary remnants of the Triassic medium-pressure metamorphic belt. On the basis of these new lines of information, the South China-related origin of the main part of Japan is confirmed, whereas the Hida and Oki belts along the Japan Sea are identified as detached fragments of North China block. Summarizing all of these results, a series of revised paleogeographic maps of Japan from the Late Neoproterozoic to the Miocene is illustrated.

著者

磯崎 行雄

出版者

一般社団法人 日本地質学会

雑誌

地質学雑誌 (ISSN:00167630)

巻号頁・発行日

vol.100, no.7, pp.XIX-XX, 1994 (Released:2010-11-26)

著者

磯崎 行雄 丸山 茂徳

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.100, no.5, pp.697-761, 1991-10-25 (Released:2010-10-13)

参考文献数

195

被引用文献数

186 207

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The Japanese Islands consist fundamentally of late Paleozoic to Cenozoic accretionary complexes that formed in situ in a subduction zone along the East Asian continental margin, i.e. 2.0 Ga Yangtze craton (South China) and 450 Ma fore-arc ophiolite. Recent research utilizing microfossil and radiometric dating has distinguished several major accretionary complexes, including high-P/T metamorphosed parts, and subordinate ophiolites. In particular, recognition of oceanic plate stratigraphy and age of subduction-related metamorphism for individual accretionary complex allows the geotectonic subdivision of the Japanese Islands be emended with a new definition of geotectonic units and their mutual boundaries. Removing the effect of arcrelated magmatism and secondary tectonic modification by microplate activities such as backarc basin opening, fore-arc sliver movement, and arc-collision, a remarkable oceanward younging polarity is recognized among the accretionary complexes. This polarity in growth is well observed in Southwest Japan where seven distinct units occur, i.e. from the Japan Sea side to the Pacific side: 400-300 Ma high-P/T schists, Permian (250 Ma) accretionary complex, 230-180 Ma high-P/T schists, Jurassic (180-140 Ma) accretionary complex, 100 Ma high-P/T schists, Late Cretaceous (80 Ma) accretionary complex, and Tertiary (50-20 Ma) accretionary complex. The sinuous surface trajectories of these geotectonic boundaries and occurrence of several tectonic outliers and windows indicate that all these complexes, including high-P/T schists, occur as subhorizontal (or gently northward dipping) thin tectonic unit, i. e. nappe. Thus the Japanese Islands form a huge pile of nappes that become younger structurally downward to the modern Nankai accretionary complex. What is remarkable in this subhorizontal orogen is that high-P/T units are tectonically intercalated between low-P units, e. g. the thin nappe of 100 Ma Sanbagawa blueschists between Jurassic and Late Cretaceous accretionary complexes of the prehnite-pumpellyite facies. Uplift of the Sanbagawa high-P/T unit appears to correlate with the arrival of the Kula/Pacific spreading ridge at the trench, suggesting that this high-P/T accretionary complex may have been extruded and uplifted into low-P domain in fore-arc by buoyant subduction of the spreading ridge at the trench. Evidence of ridge subduction at that time is supported by reconstructed paleoplate motion and the coeval climax of arc-related Ry-oke magmatism associated with low-P/T regional metamorphism. Formation of older high-P/T blueschist nappes sandwiched between low-P units can be explained likewise. Subduction of major spreading ridges seems most critical for the episodic oceanward development not only of subhorizontal high-P/T nappes but also of continent side granitic belts.

著者

磯崎 行雄 丸山 茂徳 青木 一勝 中間 隆晃 宮下 敦 大藤 茂

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.119, no.6, pp.999-1053, 2010-12-25 (Released:2011-03-17)

参考文献数

145

被引用文献数

26 74

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The geotectonic subdivision and relevant definitions of geotectonic units in the Japanese Islands are revised on the basis of new data, particularly with detrital zircon dating of U-Pb ages and seismic profiling of the deep arc crust across the islands. In addition to the final confirmation of the subhorizontal structures of the Paleozoic to Cenozoic accretionary complexes and their high-P/T metamorphosed equivalents, several new aspects were recognized; i.e., detection of the eastern extension of the collisional suture between the Sino-Korean and Yangtze cratons in the Higo belt with medium-pressure-type metamorphism in SW Japan, and separation of the traditional Sanbagawa belt into two distinct metamorphic belts characterized by mutually different ages of protolith AC-formation and peak metamorphism. The occurrence and consumption of 4 Paleozoic to Mesozoic granite batholiths, as major provenances for the ancient Japanese Islands, are documented by detrital zircon dating of Paleozoic–Mesozoic sandstones. With respect to these new findings, the definitions of unit boundaries were thoroughly revised in terms of chronological spectrum in “ocean plate stratigraphy–metamorphism”. The geological significance of 5 major tectonic lines (faults) of the Pacific-type (or Miyashiro-type) orogen in Japan, i.e., the Nagato–Hida marginal TL, Osayama–Omi TL, Ishigaki–Kuga TL, Paleo–Median TL, and Butsuzo TL, is discussed. The current revision of the geotectonic subdivision and definitions of component units and their mutual boundaries leads to the following conclusions, which challenge the conventional understanding of the orogenic history of the Japanese Islands. (1) Proto-Japan in the Early Paleozoic was located closer to the South China (Yangtze) craton rather than the North China (Sino–Korean) craton. (2) Ever since 520 Ma, subduction of past Pacific ocean floors formed mature arc-trench systems with a full set of granite batholith, fore-arc basin, accretionary complex, and high-P/T metamorphosed equivalents at least 5 times; however, the former 4 sets were almost completely destroyed, with the exception of smaller tectonic blocks that currently occur within serpentinite mélange. (3) Tectonic erosion played a significant role in consuming ancient fore-arc crusts including 4 granite batholiths of the Paleozoic to mid-Mesozoic. (4) Serpentine mélange represents the former Wadati–Benioff plane along which tectonic erosion took place. (5) The Japanese Islands, which basically developed along the Yangtze continental margin, have experienced multiple episodes of oceanward growth and continentward retreat due to alternating subduction-accretion and tectonic erosion. (6) Net production of juvenile crust occurred on a large scale along the Japan margin during the 500 million year-long oceanic subduction regime since the Cambrian; however, intensive tectonic erosion effectively erased the older crusts from the surface and enriched the underlying sub-arc mantle with heat-generating continental material.

著者

磯崎 行雄 丸山 茂徳 柳井 修一

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.119, no.2, pp.378-391, 2010-04-25 (Released:2010-07-06)

参考文献数

72

被引用文献数

11 9

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A new historical review is presented on the progress of the geological sciences in Japan since the Meiji revolution in 1868. Geological knowledge, particularly studies of the geotectonic evolution and orogenic aspects, of the Japanese Islands has progressed through three distinct phases; (1) non-science stage, (2) colonial science stage, and (3) independent science stage, as modeled by Basalla (1967), who demonstrated a general pattern of transplanting cutting-edge scientific/technological knowledge from western Europe to the rest of the world. During the “non-science” stage from the 1860s to the 1890s, major geological aspects of the Japanese Islands, together with discoveries of unusual rocks, fossils etc., were initially described by foreign geologists (e.g. E. Naumann). In contrast, almost nothing was contributed by domestic geologists. During the “colonial science” stage, from the 1900s to the 1980s, research and education systems were transplanted effectively from western European countries. For example, applying the purely imported concept of geosyncline, the geotectonic history of the Japanese Islands was summarized for the first time by domestic geologists (e.g., Kobayashi, 1941; Minato et al., 1965 etc.). The almost unidirectional acceptance of plate tectonics also followed at this stage, with the exception of the rare but outstanding contribution of A. Miyashiro during the 1960s-1970s. During the “independent science” stage from the 1980s, various new ideas and original techniques in geology were proposed by Japanese geologists with lesser help from the western countries than before; i.e., practical criteria for identifying ancient accretionary complex, exhumation tectonic of ultrahigh to high-P/T metamorphic rocks, and subhorizontal growth framework of subduction-related orogens. Furthermore, in the first decade of the 21st century, the geological science in Japan entered stage of (4), “exporting science” with the introduction of new paradigms, such as the application of detrital zircon chronology to subduction-related orogens, which efficiently recognizes new geotectonic subdivisions and allows paleogeographical reconstruction with much higher resolution than before. These new paradigms (ideas, techniques) from Japan are now on sale for applying to the rest of the world.

著者

太田 彩乃 勘米良 亀齢 磯崎 行雄

出版者

日本地質学会

雑誌

地質學雜誌 (ISSN:00167630)

巻号頁・発行日

vol.106, no.12, pp.853-864, 2000-12-15

被引用文献数

4 7

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宮崎県北部, 高千穂町上村のペルム系石灰岩, 岩戸層と三田井層の新露頭において, 岩相層序および生層序を検討した.その結果, 整合に累重する4つの化石帯, すなわち下位よりLepidolina帯および無化石帯(岩戸層), Codonofusiella-Reichelina帯およびPalaeofusulina帯(三田井層)が識別された.前二者は南中国の茅口階に, 後二者はそれぞれ呉家坪階および長興階に対比される.本石灰岩は, 西南日本外帯, 秩父累帯のジュラ紀付加体中に巨大な異地性岩体として産するが, 初生的には海洋中央部に位置していた古海山頂部に形成された浅海成石灰岩体に起源をもつ.このような遠洋浅海成石灰岩中に茅口階から長興階に至る連続セクションが確認されたのは世界で初めてであり, ペルム紀末の大量絶滅事件直前の超海洋パンサラサでの環境変化を解明する上で重要な記録が得られた.

著者

久保 健一 磯崎 行雄 松尾 基之

出版者

一般社団法人 日本地質学会

雑誌

地質学雑誌 (ISSN:00167630)

巻号頁・発行日

vol.102, no.1, pp.40-48, 1996-01-15 (Released:2008-04-11)

参考文献数

27

被引用文献数

23 29

著者

山本 純之 磯崎 行雄

出版者

日本地質学会

雑誌

日本地質学会学術大会講演要旨

巻号頁・発行日

vol.113, 2006-09-08

著者

佐藤 友彦 磯崎 行雄 小宮 剛 丸山 茂徳

出版者

日本地質学会

雑誌

日本地質学会学術大会講演要旨 (ISSN:13483935)

巻号頁・発行日

vol.115, 2008-09-15

著者

磯崎 行雄 松尾 基之 川幡 穂高 可児 智美

出版者

東京大学

雑誌

基盤研究(S)

巻号頁・発行日

2008

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カンブリア紀初めと古生代末の地球環境変動・絶滅事件について、クロアチア、中国雲南省、さらに岐阜県赤坂・石山、宮崎県高千穂、宮城県気仙沼での野外調査/ボーリング掘削および炭素・ストロンチウム同位体などの分析を行い、古生代末事件が地球磁場強度低下と銀河宇宙線増化による地球規模の寒冷化で始まったこと、またカンブリア紀初期の爆発的進化が特異な南中国のプルーム活動域で局地的に始まったことを初めて解明した。

著者

磯崎 行雄 笠原 順三

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.112, no.2, pp.185-186, 2003-04-25 (Released:2009-11-12)

著者

磯崎 行雄

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.114, no.3, pp.410-418, 2005-12-25 (Released:2009-11-12)

参考文献数

14

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Current trends in research on history of life are briefly reviewed. Since the 1990s study on deep past focusing on early life on Earth and Mars has become popular. This trend often called astrobiology will be a main stream in earth science in this century because it involves the latest human issues, such as global environment, energy, food, world population, and search for habitable planets outside the solar system, in addition to conventional studies on the evolution of Earth and life. Studies on chemofossils of nanometric scale and on geochemical proxies for evaluating paleoenvironments will be the most important targets in this research field. Inevitable in Japan are overhaul of the current domestic-oriented atmosphere in the geological community and deployment of a new research style under a long-term scope.

著者

大林 秀行 坂田 周平 山本 伸次 磯崎 行雄 服部 健太郎 平田 岳史

雑誌

日本地球惑星科学連合2016年大会

巻号頁・発行日

2016-03-10

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Most of the global events, such as formation of magma ocean, core-mantle segregation, crust formation, and/or chemical evolution of atmosphere, could be completed within the first 0.5 Byr of the Earth History, so called Hadean Eon. Despite the great importance of the Hadean Eon, no petrographic record can be found for this stage, and only geochemical information can be derived from small minerals such as zircons or other accessory minerals within zircons (e.g., apatite, muscovite, or biotite). For geochemical studies for Hadean Eon, many pioneering studies have been made based on the isotope geochemistry on zircons collected from Jack Hills and Mt. Narryer, Western Australia. It is widely recognized that zircons collected from these area have been thought one of the most principal clues for Hadean studies. Moreover, further detailed studies have been carried out from small inclusions in zircon crystals. Zircons from Jack Hills contain various mineral inclusions such as muscovite, quartz, biotite, apatite and so on, and about two-thirds of them are muscovite and quartz, probably due to secondary replacement of primary apatite (Hopkins et al., 2008, Rasmussen et al., 2011). Recently, biogenic carbon, as graphite inclusion, was recovered from 4.1 Ga zircon, but an abundance of carbon-bearing Jack Hills zircons of only about 1-in-10,000 (Bell et al., 2015). In addition, the percentage of Hadean zircons to detrital zircons in Jack Hills was as small as 7% (Holden et al., 2009). For these reasons, large number of age data for zircon grains must be defined to derive reliable and objective information concerning the Hadean history of the Earth. To overcome this, we have developed new analytical technique to define precise age data from combination of U-Pb (Pb-Pb) dating method with high sample throughput.We have developed rapid and precise dating technique for zircons using laser ablation ICP-mass spectrometer (LA-ICP-MS), equipped with two Daly ion collectors (Nu Plasma IID, Wrexham, UK). Laser ablation instrument used in this study was ESI NWR193 laser ablation system (New Wave Research, Oregon, USA). Combination of multiple collector-ICPMS system and ArF Excimer laser ablation system enables us to measure Pb-Pb age for the sample within 10 second/spot, and uncertainties in the resulting Pb-Pb age data can be minimized by the multiple-collector system setup. Based on the age determination system using LA-MC-ICPMS technique, we just started to measure Pb-Pb age data from 180 grains of zircons within an hour . In this presentation, difference in the resulting age histogram for the zircons collected from Jack Hills will be discussed, and detailed observation for various inclusions in the Hadean zircons will be demonstrated in this talk.

著者

磯崎 行雄 谷本 俊郎 平田 岳史 圦本 尚義 丸山 茂徳 中村 保夫

出版者

東京大学

雑誌

基盤研究(A)

巻号頁・発行日

1996

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現在の環太平洋地域では、いずれも海洋プレートが大陸プレートの下に沈み込んでおり、典型的なプレート沈み込み帯型の造山帯をなしている。本研究計画の前半では、その造山帯成長を司る二つの主要なプロセス、すなわち付加体の形成と花崗岩帯の形成についての地質学的研究がなされ、日本列島に分布する顕生代の付加型造山帯の基本構造と形成過程が解明された。また、そこで開発された研究手法は、日本列島からみると太平洋の対岸にあたる北米西岸のカリフォルニア州のコルディレラ造山帯においても適用され、新たな成果をあげた。この一般的な造山帯形成過程に対して、都城型造山運動と命名した。これは超海洋の誕生から消滅に及ぶ一つのウイルソンサイクルの中での一般的プロセスと理解される。一方、これらのプレート沈み込み型造山帯の基本的体制が何時成立したのかについては従来不明であったが、本研究後半では、本邦における最古期岩石群の特徴に着目し、それらの起源が約7-6億年前に超大陸ロディニアが分裂した時に出現したリフト帯にあったことを明らかにした。すなわち、日本列島の成長核になる揚子地塊の海洋側に産する5億8千万年前のオフィオライト(西九州および北上山地)が太平洋の最古断片を代表することをつきとめた。この事実は、先に解明した付加型造山帯の成長極性と調和的で、揚子地塊の太平洋側大陸縁が、もともとの受動的なものから、約4.5億年前に活動的大陸縁に転換したことを示す。一つの超大陸の分裂から大海洋が生まれ、同時にそれをとりまく新しい大陸縁辺のグループが生じる。その海洋が面積を拡大していゆくと、やがて地球の反対側で別の海洋が開き始める頃には、もとの大陸縁はプレート収束帯に進化してゆくという大陸縁造山帯の一般的成長プロセスが、日本列島の研究から導かれたことになる。

著者

磯崎 行雄

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.117, no.1, pp.268-269, 2008-02-25 (Released:2010-02-10)

参考文献数

3

被引用文献数

1 1

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Andrija Mohorovičić (1857-1936) is a world-famous Croatian geophysicist and the discoverer of the Earth's crust/mantle boundary known as the Moho-discontinuity. The historical seismometer used by A. Mohorovičić to detect the Moho in 1909 is still maintained in working conditions, and is displayed in the Department of Geophysics of the University of Zagreb, Croatia, together with memorabilia from his office.

著者

黒川 顕 戎崎 俊一 丸山 茂徳 原 正彦 クリーヴス ヘンダーソン 鎌形 洋一 磯崎 行雄 青野 真士

出版者

国立遺伝学研究所

雑誌

新学術領域研究(研究領域提案型)

巻号頁・発行日

2014-07-10

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H29年度は立案した計画に基づき、以下の活動を実施した。1. キックオフWSの開催:H29年度から14課題からなる第二期の公募班が新たに領域に加わった。計画班と公募班との連携を強めるために、キックオフWSを開催した。2. 中規模WSの開催:領域全体での合同班会議を白馬八方文化会館にて開催した。3. Origin of Life 国際シンポジウムの開催:新学術領域研究「ゆらぎと構造の協奏」と合同で、化学進化および初期生命体に関する国際シンポジウムを開催した。4. 総括班会議を年6回開催した。会議後には計画班横断WSを開催し計画班間の連携を強めた。5. 地球生命アーカイブの開発:微生物統合データベースの開発ならびに東工大地球史資料館のデータベースの整理作業を継続した。また、領域の最先端研究内容をわかりやすく発信するために製作している映像ライブラリ「全地球史アトラス映像」をインターネットで配信できるよう、YouTubeチャンネルを開設した。さらに、「全地球史アトラス映像vol.3」を完成させた。6. 地域活性化イベント:中規模WSと同時に長野県白馬村役場にて教育講演会「白馬とカガクの奇跡episode2」を長野県教育委員会および白馬村の後援を受け開催し、最新の研究成果および白馬と生命起源との関係性に関する講演を行った。また、白馬高校(2017年10月19日)および大町岳陽高校(2017年12月21日)に出張講義を行った。また、大町岳陽高校では、理数科の生徒の課題研究に協力し、3つの班の課題を引き受け、共同研究を実施した。3班のうち1班の研究は、日本ゲノム微生物学会第12回年会にてポスター発表をした。

著者

磯崎 行雄 澤木 佑介 佐野 有司 高畑 直人 尾上 哲治 石川 晃

出版者

東京大学

雑誌

基盤研究(A)

巻号頁・発行日

2019-04-01

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カンブリア紀以降の古生代で3回の大量絶滅(オルドビス紀末、デボン紀後期、およびペルム紀末)がおきた。どれもグローバル寒冷化期に起きたが、その原因は未特定である。オルドビス紀末には大気CO2分圧が現世の10倍あったにもかかわらず大規模寒冷化がおきた。一方ペルム紀末絶滅時に地球外起源3Heが大量流入したことから、大量の星間塵の集中落下で寒冷化と絶滅がおきた可能性が指摘されている。本計画は、古生代の3回の大量絶滅と寒冷化との因果関係の解明を目的とし、過去の深海堆積物中の絶滅境界層から3He同位体異常などの地球外起源物質流入の定量的検出を試みる。主要絶滅事件に関する新たな統一的説明を目指す。

著者

磯崎 行雄

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.108, no.5, pp.643-649, 1999-10-25 (Released:2009-11-12)

参考文献数

6

著者

沢田 輝 磯崎 行雄 堤 之恭 飯塚 毅

出版者

一般社団法人 日本地質学会

雑誌

日本地質学会学術大会講演要旨 (ISSN:13483935)

巻号頁・発行日

vol.2015, 2015

著者

久保 健一 磯崎 行雄 松尾 基之

出版者

日本地質学会

雑誌

地質學雜誌 (ISSN:00167630)

巻号頁・発行日

vol.102, no.1, pp.40-48, 1996-01-15

参考文献数

27

被引用文献数

1 29