2024/02/29 更新

写真a

チョウ テンイチ
張 天逸
所属
附属機関・学校 データ科学センター
職名
助教

経歴

  • 2023年04月
    -
    継続中

    早稲田大学   データ科学センター   助教

  • 2021年04月
    -
    2023年03月

    早稲田大学   理工学術院   日本学術振興会特別研究員(DC2)

  • 2017年04月
    -
    2022年07月

    早稲田大学   教育学部   授業TA

学歴

  • 2018年04月
    -
    2023年03月

    早稲田大学   大学院創造理工学研究科   地球・環境資源理工学専攻  

  • 2014年04月
    -
    2018年03月

    早稲田大学   教育学部   理学科  

    地球科学専修

研究分野

  • 固体地球科学 / 大気水圏科学 / 地球生命科学

研究キーワード

  • 地球温暖化

  • 化学風化

  • 白亜紀

  • 三畳紀

  • 組成データ解析

  • 堆積学

  • 古環境学

▼全件表示

受賞

  • アーリーバードプログラム 共同研究計画発表 最優秀賞

    2022年03月   早稲田大学理工学術院総合研究所  

  • The Best Poster Presentation Award

    2019年10月   International Geoscience Programme 679  

 

論文

  • Did changes in terrigenous components of deep-sea cherts across the end-Triassic extinction relate to Central Atlantic magmatic province volcanism?

    Masayuki Ikeda, Tenichi Cho, Maximilien Bôle

    Frontiers in Earth Science   11  2023年07月

     概要を見る

    The end-Triassic mass extinction event (ETE) is considered to be linked with the emplacement of the Central Atlantic magmatic province (CAMP), yet their temporal relation and underlying nature of global environmental and biotic changes remain controversial. A drastic radiolarian faunal turnover was associated with deep-sea acidification and changes in the chemical composition of pelagic terrigenous components, which were interpreted as the results of increased CAMP-derived materials, such as Fe2O3/Al2O3, MgO/Al2O3, and SiO2/Al2O3, without statistical tests. Here, we re-examined these CAMP-like signatures in terms of changes in the chemical composition of the Triassic–Jurassic pelagic deep-sea chert succession in Japan. Our newly compiled dataset suggests that changes in Fe2O3/Al2O3 and MgO/Al2O3 across the ETE were not significant, and thus, they may not be appropriate proxies for CAMP-derived material, potentially due to the dissolution of iron by ocean acidification and the formation of chlorite during diagenesis, respectively. Decreased SiO2/Al2O3 was also considered to have been reflected in increased CAMP-related dust flux and/or decreased biosiliceous productivity, but a slight increase in the Al2O3/TiO2 ratio (a biosiliceous productivity proxy) and an increase in shale bed thickness (dust flux proxy) across the radiolarian ETE imply increased eolian dust flux rather than decreased productivity. Furthermore, statistically significant Na enrichment at the radiolarian ETE level might be related to CAMP volcanism and/or associated changes in the source areas of eolian dust.

    DOI

    Scopus

  • Shallow- and deep-ocean Fe cycling and redox evolution across the Pliensbachian–Toarcian boundary and Toarcian Oceanic Anoxic Event in Panthalassa

    Wenhan Chen, David B. Kemp, Tianchen He, Robert J. Newton, Yijun Xiong, Hugh C. Jenkyns, Kentaro Izumi, Tenichi Cho, Chunju Huang, Simon W. Poulton

    Earth and Planetary Science Letters   602  2023年01月

     概要を見る

    The late Pliensbachian to early Toarcian was characterized by major climatic and environmental changes, encompassing the early Toarcian Oceanic Anoxic Event (T-OAE, or Jenkyns Event, ∼183 Ma) and the preceding Pliensbachian–Toarcian boundary event (Pl/To). Information on seawater redox conditions through this time interval has thus far come mainly from European sections deposited in hydrographically restricted basins, and hence our understanding of the redox evolution of the open ocean (and in particular Panthalassa – the largest ocean to have existed) is limited. Here, we present high-resolution Fe-speciation and redox-sensitive trace metal data from two Panthalassic Ocean sections across the Pl/To and the T-OAE intervals, one deposited in deep water (paleo-water depth >∼2.7 km) and the other on a shallow margin (paleo-water depth likely <∼50 m). Data from the deep-water open-ocean site indicate anoxic-ferruginous conditions from the late Pliensbachian to the onset of the T-OAE, with a rather fluctuating redox state alternating between oxic and anoxic/euxinic conditions across the Pl/To boundary. At least intermittent bottom-water euxinia characterized the T-OAE, followed by a subsequent transition toward more oxygenated conditions. By contrast, trace metal data from the shallow margin site indicate that oxygenated to possibly suboxic conditions prevailed. However, elevated highly reactive iron contents, dominated by Fe (oxyhydr)oxides, characterize this shallow-water site. These observations suggest that upwelling, driven in part by increased sea level and prevailing winds from the open ocean, brought anoxic-ferruginous waters onto the shelf, whereupon Fe2+ oxidation was initiated in oxic shallow waters.

    DOI

    Scopus

    4
    被引用数
    (Scopus)
  • A robust chemical weathering index for sediments containing authigenic and biogenic materials

    Tenichi Cho, Tohru Ohta

    Palaeogeography, Palaeoclimatology, Palaeoecology   608  2022年12月

     概要を見る

    Chemical weathering is an important process at Earth's surface. Given that the chemical composition of sediments reflects the weathering environment in which they were generated, this can provide insights into the intensity and style of weathering during the past. Weathering indices calculated from the whole-rock geochemical compositions of sedimentary rocks are widely used. However, these indices have limitations, such as contamination by non-silicate minerals. To develop a weathering index widely applicable to sedimentary rocks formed under various conditions, we used compositional data and multivariate statistics to analyse a dataset for igneous rocks and their weathering profiles. The chemical variations of the igneous rocks and weathering trends were independently extracted from the dataset, and a new weathering index (the robust weathering (RW) index) is proposed. The applicability of the RW index was assessed using saprolite profiles and zonal soils. We further applied the RW index to a carbonate-rich paleosol to test its use in studies of paleoclimate. The RW index is robust even for sediments containing a large amount of non-silicate materials, and thus enables comparison of the weathering intensity of a wide range of sedimentary rocks. Spatial–temporal reconstructions of paleo-weathering conditions will be improved by applying the RW index to terrestrial and marine sediments.

    DOI

    Scopus

    3
    被引用数
    (Scopus)
  • Major sulfur cycle perturbations in the Panthalassic Ocean across the Pliensbachian-Toarcian boundary and the Toarcian Oceanic Anoxic Event

    Wenhan Chen, David B. Kemp, Robert J. Newton, Tianchen He, Chunju Huang, Tenichi Cho, Kentaro Izumi

    Global and Planetary Change   215  2022年08月

     概要を見る

    The early Toarcian Oceanic Anoxic Event (T-OAE, ~183 Ma) was characterized by marine deoxygenation and the burial of organic-rich sediments at numerous localities worldwide. However, the extent of marine anoxia and its impact on the sulfur cycle during the T-OAE is currently poorly understood. Here, stable sulfur isotopes of reduced metal-bound sulfur (δ34Spyrite) and pyrite sulfur concentrations (SPY) have been analyzed across the Pliensbachian-Toarcian boundary (Pl-To) and the T-OAE from the Sakahogi and Sakuraguchi-dani sections (Japan), which were deposited in the deep and shallow Panthalassic Ocean, respectively. Our data reveal marked positive δ34Spyrite excursions of >10‰ across both the Pl-To and the T-OAE at Sakahogi, coincident with increases in SPY, and a positive excursion of >20‰ at the onset of the T-OAE at Sakuraguchi-dani. Whilst the development of deep-water anoxic/euxinic conditions could have resulted in an enhanced burial of pyrite, and also partly contributed to the positive excursion of δ34Spyrite, variations in δ34Spyrite at Sakahogi were most likely controlled by elevated export production and/or preservation. On the shallow shelf generally low and highly variable SPY and the positive shift in δ34Spyrite were likely attributable mainly to elevated sedimentation rates, with redox playing only a minor role in controlling pyrite abundance. Our discovery of a positive δ34Spyrite excursion across the Pl-To at Sakahogi indicates a hitherto unrecognized perturbation to the deep-water sulfur cycle, potentially associated with increased seafloor organic matter flux and pyrite burial at this time, consistent with a transient interval of anoxia.

    DOI

    Scopus

    4
    被引用数
    (Scopus)
  • Increased Terrigenous Supply to the Pelagic Panthalassa Superocean Across the Carnian Pluvial Episode: A Possible Link With Extensive Aridification in the Pangean Interior

    Tenichi Cho, Masayuki Ikeda, Tohru Ohta

    Frontiers in Earth Science   10  2022年06月

     概要を見る

    In the Late Triassic, a global environmental change called the Carnian Pluvial Episode (CPE) emerged, causing major biological turnover. The CPE has been recognized by siliciclastic input to sedimentary basins, multiple carbon isotope perturbations, and climate proxies for humidification. The CPE is considered to have been associated with increased atmospheric pCO2 from eruptions of large igneous provinces. However, the nature of this global environmental perturbation on the continents is still not well understood. Here we present a geochemical analysis of a pelagic deep-sea bedded chert sequence across the CPE in the Jurassic accretionary complex of Mino terrane, central Japan. Fluctuations in terrigenous material supply were reconstructed using Principal Component Analysis of major element compositions. The first principal component positively correlates with elements enriched in clay minerals such as Al2O3, whereas it negatively correlates with CaO, P2O5, and MnO, derived from apatite and manganese. A sudden increase in terrigenous supply was detected around the Julian/Tuvalian boundary, suggesting that CPE-related siliciclastic input also occurred in the abyssal plain environment. The terrigenous supply returned to the pre-CPE state in the Tuvalian. Since the terrigenous material supplied to the abyssal plain is thought to be derived from eolian dust blown from continental arid regions, the increasing terrigenous supply detected in the pelagic deep-sea chert succession may indicate extensive aridification. This result seems to conflict with the common view of the CPE as a humidification event. This contradiction possibly suggests that the extensive aridification occurred within the interior of the supercontinent Pangea, while hydrological circulation enhanced on the coastal region during the CPE.

    DOI

    Scopus

    3
    被引用数
    (Scopus)
  • Deep-ocean anoxia across the Pliensbachian-Toarcian boundary and the Toarcian Oceanic Anoxic Event in the Panthalassic Ocean

    David B. Kemp, Wenhan Chen, Tenichi Cho, Thomas J. Algeo, Jun Shen, Masayuki Ikeda

    Global and Planetary Change   212  2022年05月

     概要を見る

    The early Toarcian Oceanic Anoxic Event (T-OAE, or Jenkyns Event, ~183 million years ago) was a major hyperthermal and global carbon-cycle perturbation, likely associated with the release of a substantial volume of 12C-enriched carbon to the Earth's surface. Seawater deoxygenation and the associated deposition of organic-rich facies during this event have been noted in many locations around the world, but evidence for pervasive and extreme oceanic anoxia has thus far been described mainly from European sections deposited in hydrographically restricted basins. Here we present new geochemical data on redox changes during the T-OAE, as well as the preceding Pliensbachian-Toarcian boundary (Pl/To) event, from a deep Panthalassic Ocean site at Inuyama, Japan. Redox-sensitive trace element data reveal an extended interval of seawater deoxygenation that began prior to the Pl/To and continued to the end of the T-OAE. A marked expansion of anoxic and possibly euxinic conditions to the seafloor occurred during both the Pl/To and T-OAE, accompanied by increased organic carbon burial. During these intervals of severe deep-ocean deoxygenation, our data suggest a global drawdown of trace elements such as Mo, U and As. Our findings highlight that: (1) the Panthalassic Ocean was likely an important locus of deoxygenation and organic carbon burial during the early Toarcian, and (2) the spread of anoxia during the T-OAE was a globally distributed phenomenon.

    DOI

    Scopus

    13
    被引用数
    (Scopus)

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共同研究・競争的資金等の研究課題

  • 火成活動・気候変動・生物進化の関係解明に向けたカーニアン期多雨事象の詳細解析

    日本学術振興会  科学研究費助成事業 特別研究員奨励費

    研究期間:

    2021年04月
    -
    2023年03月
     

    張 天逸

Misc

  • 生物源物質及び続成由来物質の混入に強固な風化指標の構築と東アジア白亜系への適用

    張 天逸, 太田 亨, 李 罡

    地球環境史学会    2023年12月

  • Introduction of a robust chemical weathering index for sediments containing authigenic and biogenic materials and its application to Cretaceous strata distributed in SE Asia

    2nd Asian Paleontological Congress    2023年08月

  • 美濃帯層状チャートを用いた遠洋域への風成塵供給量の復元:Carnian Pluvial Episodeにおける陸域環境変動への示唆

    日本堆積学会2022年オンライン大会講演要旨    2022年

  • Shallow and deep ocean Fe cycling and redox evolution across the Pliensbachian-Toarcian

    Chen, W, He, T, Kemp, D, Xiong, Y, Izumi, K, Cho, T, Huang, C, Newton, R, Poulton, S

    Goldschmidt conference 2022 (virtual), European Association of Geochemistry.    2022年

  • 生物源物質の混入と続成作用による化学組成改変を補正する化学風化指標(RW index)の提示

    張 天逸, 太田 亨

    日本地質学会学術大会講演要旨   2022   170  2022年

     概要を見る

    大陸地殻の化学風化は,気候条件を反映して進行するため,過去の気候の復元に活用できる指標となる.また,化学風化は大気CO2の消費を通して気候を寒冷化させることで地球環境の温度調整を担うことや,大陸地殻から海洋への栄養塩供給を担うことで,地球表層環境を制御する重要なプロセスである.風化生成物である砕屑物の化学組成は,生成当時の風化強度を反映する.したがって,砕屑物の主要元素を用いた風化指標は,過去の風化度を見積もる際に良く用いられてきた(Nesbitt and Young, 1982).しかし,堆積物・堆積岩の化学組成は,風化強度のみによって規定されるわけではなく,源岩の化学組成の差異によっても変化する.この問題を是正したのが風化指標W値(Ohta and Arai, 2007)であり,化学風化と源岩組成に依存した化学組成情報を独立化させた.しかしながら,W値は,堆積物にしばしば混入する生物源や続成起源物質(シリカ,カルサイト等)による化学組成変化の影響を補正できていない.

    そこで,本研究ではこの問題を解決するために,生物源や続成起源物質からの寄与が考えられるSiO2,CaO,P2O5を用いない新たな化学風化指標RW indexを構築した.これは,様々な組成をもつ未風化な火成岩と現世風化プロファイルの主要元素のデータセットに多変量統計解析を適用することにより,SiO2,CaO,P2O5の値を使用せずに源岩組成トレンドと化学風化トレンドを統計的に独立に抽出することで構築されたものである.火成岩のデータはUSGS,GSJの標準試料などを,現世風化プロファイルについては熱帯雨林気候や温帯気候,乾燥気候,氷雪気候に発達するサプロライトやラテライトなどを使用した.この組成データのデータセットについて有心対数比変換を施した後に,独立成分分析を適用し,源岩組成(苦鉄質~珪長質)の差異によるトレンドと化学風化のトレンドの2つの独立成分を抽出した.この主要元素の対数の線形結合で表される2つの軸を,等長対数比変換の逆写像を用いることで,新たなデータを投影することのできる三角図に整備した(mafic-felsic-RW diagram).

    RW indexの構築には使用していない現世の風化プロファイルや古土壌のデータにRW indexを適用することで,RW indexの有用性を確認した.花崗岩と玄武岩のサプロライトプロファイルにRW indexを適用したところ,地中の未風化の源岩から風化が進行している表層に近づくに伴いRW indexの値が上昇した.また,RW indexを異なる気候帯に発達する現世土壌に適用した結果,寒冷気候,温暖気候,熱帯雨林気候の順に化学風化度を反映してRW indexの値が増加した.さらに,カルサイトノジュールを多く含む古土壌プロファイルにRW indexを適用した結果,カルサイトの濃度変化傾向とは独立に,土壌表面に近づくにつれて風化度が上昇する傾向を示した.以上の結果より,RW indexは「異なる源岩組成をもつ砕屑物について適用可能」,「多元素を用いているために特定の元素濃度に影響されづらい」といったW値の利点を引き継ぎつつ,シリカ,カルサイト,アパタイトといった生物・続成起源物質の混入の影響にも強固な指標であることが確かめられた.RW indexにより,続成や生物源のシリカ,カルサイトを多量に含む浅海堆積物や陸成堆積物においても,追加の実験や補正を必要とせずにケイ酸塩化学風化度を簡便に算出することが可能となったため,今後の陸成層・海成層双方を用いた複合的な古環境解析においての適用が期待される.

    文献:

    Nesbitt and Young, 1982, Nature 299, 715-717. Ohta and Arai, 2007, Chem. Geol. 240, 280-297.

    DOI

  • Reconstruction of climate condition in the Carnian from bedded chert by using a new index of chemical weathering

    Cho, T

    JpGU-AGU Joint Meeting (virtual), Japan Geoscience Union.    2020年

  • A robust chemical weathering index applicable to a wide range of sedimentary rocks

    Cho, T, Ohta, T

    Goldschmidt conference 2020 (virtual), European Association of Geochemistry.    2020年

  • Paleoclimate evaluation during the mid-Cretaceous in Zhejiang Province, southeast China

    Okano, K, Nakano, A, Cho, T, Ohta, T, Li, G

    35th IAS Meeting of Sedimentology (virtual) Book of Abstracts International Association of Sedimentologist     331 - 331  2020年

  • Evaluation of hinterland weathering and paleoclimate of the Cretaceous strata in the Sichuan basin, central China

    Cho, T, Mantani, H, Ohta, T, Li G

    Japan Geoscience Union Meeting 2019 (Chiba, Japan), Japan Geoscience Union.    2019年

  • Late Triassic continental weathering fluctuation recorded in pelagic sediments distributed in Inuyama section, central Japan

    Cho, T, Ohta, T

    34th IAS Meeting of Sedimentology (Rome, Italy) Book of Abstracts International Association of Sedimentologist.     251 - 251  2019年

  • Evaluation of Cretaceous hinterland weathering and climate in the Sichuan Basin SW China

    Cho, T, Mantani, H, Ohta, T. Li, G

    Open Journal of Geology   9   696 - 699  2019年

  • 犬山層状チャートに記録された後背地風化度変動と後期三畳紀湿潤化イベントの関係

    張 天逸, 海老澤 駿, 太田 亨

    日本地質学会学術大会講演要旨   2019   453  2019年

    DOI CiNii

  • 犬山層状チャートの挟在泥岩化学組成を用いた風成塵供給量の復元によるパンゲア・メガモンスーン仮説の検証

    張 天逸, 太田 亨

    日本地質学会学術大会講演要旨   2018   475  2018年

    DOI CiNii

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現在担当している科目

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他学部・他研究科等兼任情報

  • 附属機関・学校   グローバルエデュケーションセンター

特定課題制度(学内資金)

  • 顕生代の堆積岩に適用可能な定量的な古気候指標の開発

    2023年  

     概要を見る

    堆積岩の化学組成は,過去の風化度の情報を保持していることから,古気候解析に有用である.本研究では,様々な気候帯に発達する現世土壌の化学組成と現地の気象データを比較して,多変量統計解析の手法を用いて化学組成から温度や降水量といった具体的な気候パラメータを復元する指標を構築するための基礎研究を行った.解析データ取得のため,現世土壌の化学組成の文献調査による収集を行った.実際に古気候解析に適用するデータの取得のため,蛍光X線分光法,誘導結合プラズマ質量分析法によって,三畳系の堆積岩試料の分析を行った.現段階での予察的な解析結果を「第1回早稲田大学データ科学研究交流会」において発表した.