Challenge to 30 ppm TOC: Does carbon isotope analysis on pelagic chert possible only with popular method?

• Project/Area Number: 16K13897
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Stratigraphy/Paleontology
• Research Institution: Kanazawa University
• Principal Investigator: Hasegawa Takashi 金沢大学, 地球社会基盤学系, 教授 (50272943)
• Co-Investigator(Kenkyū-buntansha): 松岡 篤 新潟大学, 自然科学系, 教授 (00183947)
• Research Collaborator: Goto Akiko S. ; Hasebe Keiichiro
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000); Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 炭素同位体 / 古環境 / 層序 / 対比 / チャート / 炭素同位体比 / 質量分析 / 有機炭素 / 有機物 / 質量分析装置 / 微量分析 / 地球化学 / 地質学 / 環境分析 / 環境変動

Outline of Final Research Achievements

To achieve carbon isotope analysis on samples with very low TOC, the minimum amount of introduced carbon, and minimum TOC available for regular EA-IRMS analysis was investigated. Our regular EA-IRMS system could reproduce the results with 10 micro gram carbon or 0.025% TOC samples. Therefore, 0.025% TOC is concluded to be a minimum TOC for regular carbon isotope analysis with EA-IRMS system. For samples with TOC<0.025%, pre-sample treatment with hydrofluoric acid to reduce the volume of silicate is required for the use of EA-IRMS. Or the sample introduction portion of the analytical system should be reconstructed to reduce the dead volume.

Academic Significance and Societal Importance of the Research Achievements

TOCが小さい試料を漠然とEA-IRMS法で他試料と同様に分析しても，一応のデータは出てしまう．それをそのまま分析値として用いる研究者が散見されたが，そのような分析に信頼性がないことが改めてわかった．一方，標準試料量を変えて特別に分析シーケンスを構築するなどすれば，0.025% TOCでも十分実用的なデータを出し得ることも分かった．それ以下のTOCであれば，分析装置だけでなくサンプルを包む錫箔に含まれる炭素の影響などもあり，EA-IRMS法での分析は困難であることが判った．TOC＝0.025%を目安としてフッ酸処理するものとしないものを見極めて，効率的に研究を進められるようになった．

Research Products

• [Int'l Joint Research] 南京大学(中国)
• [Journal Article] Fractionation of stable nitrogen isotopes (¹⁵N/¹⁴N) during enzymatic deamination of glutamic acid: Implications for mass and energy transfers in the biosphere (2018)
  • Author(s): A.S Goto, M.T. Miura, T. Korenaga, T. Hasegawa, N. Ohkouchi, Y. Chikaraizhi
  • Journal Title: GEOCHEMICAL JOURNAL Volume: 52 Issue: 3 Pages: 273-280
  • DOI: 10.2343/geochemj.2.0513
  • NAID: 130007379059
  • ISSN: 0016-7002, 1880-5973
  • Year and Date: 2018-05-30
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Tectonic, paleoclimate, and paleoceanographic history of high-latitude southern margins of Australia during the Cretaceous (2018)
  • Author(s): B.T. Huber, R.W. Hobbs, K.A. Bogus, and the Expedition 369 Scientists (Hasegawa, T. 順不同)
  • Journal Title: International Ocean Discovery Program Expedition 369 Preliminary Report Volume: - Pages: 1-33
  • DOI: 10.14379/iodp.pr.369.2018
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Origin of methane and heavier hydrocarbons entrapped within Miocene methane-seep carbonates from central Japan (2018)
  • Author(s): Miyajima Yusuke、Ijiri Akira、Miyake Akira、Hasegawa Takashi
  • Journal Title: Chemical Geology Volume: 498 Pages: 83-95
  • DOI: 10.1016/j.chemgeo.2018.09.014
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Depositional ages and characteristics of Middle-Upper Jurassic and Lower Cretaceous lacustrine deposits in southeastern Mongolia (2018)
  • Author(s): Hasegawa H., Ando H., Hasebe N., Ichinnorov N., Ohta T., Hasegawa T., Yamamoto M., Li G., Erdenetsogt, B., Heimhofer U., Murata T., Shinya H., Enerel G., Oyunjargal G., Munkhtsetseg O., Suzuki N., Irino T., Yamamoto K.
  • Journal Title: Island Arc Volume: 27 Issue: 3 Pages: 1-17
  • DOI: 10.1111/iar.12243
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Cool eastern rim of the North Pacific during Late Cretaceous time; A seep-carbonate paleothermometry from the Nanaimo Group, British Columbia (2017)
  • Author(s): Jenkins, R.G., Hasegawa, T.(責任著者, 2番/4名) et al.
  • Journal Title: Palaeogeography, Palaeoclimatology Palaeoecology Volume: 487 Pages: 407-415
  • DOI: 10.1016/j.palaeo.2017.09.027
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Excursion guide to the radiolarians of the East China Sea near Sesoko Island, Okinawa, Japan: An important research station for living radiolarian studies (2017)
  • Author(s): Matsuoka, A., Suzuki, N., Ito, T., Kimoto, K., Tuji, A., Ichinohe, R., Li, X.
  • Journal Title: Science Reports of Niigata University (Geology) Volume: 32 Pages: 103-123
  • NAID: 120006762529
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Review of microfossil-bearing clasts within upper Mesozoic strata in East Asia: staged denudation of mid-Mesozoic accretionary complexes (2017)
  • Author(s): Ito, T., Sakai, Y., Feng, Q., Matsuoka, A.
  • Journal Title: Ofioliti Volume: 42 Pages: 39-54
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Characterization ascertained from ｄ13C and D14C of particulate organic matter in surface water from a shallow and semi-closed Lake Kiba (2017)
  • Author(s): Hong, T. B, Nagao, S., Ochiai, S., Fukushi, K., Goto, A., and Hasegawa, T.
  • Journal Title: Journal of Nuclear and Radiochemical Sciences Volume: 17
  • Peer Reviewed
• [Journal Article] 白亜系の国際対比：最近の動向 (2017)
  • Author(s): 長谷川卓
  • Journal Title: 化石 Volume: 101 Pages: 75-80
  • NAID: 130007623291
  • Peer Reviewed
• [Journal Article] A late Miocene methane-seep deposit bearing methane-trapping silica minerals at Joetsu, central Japan (2016)
  • Author(s): Miyajima, Y., Watanabe, Y., Yanagisawa, Y., Amano, K., Hasegawa, T. and Shimobayashi, N.
  • Journal Title: Palaeogeography, Palaeoclimatology, Palaeoecology Volume: 455 Pages: 1-15
  • DOI: 10.1016/j.palaeo.2016.05.002
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] 白亜紀セノマニアン/チューロニアン期境界の南太平洋高緯度域における環境変動 (2018)
  • Author(s): 加藤禎理, 長谷川卓, 後藤晶子, Crampton, J.
  • Organizer: 古生物学会2018年会
• [Presentation] 南テチス海高緯度域における白亜紀セノマニアン/チューロニアン境界のOAE2:国際深海科学掘削計画(IODP)第369次航海の予察成果 (2018)
  • Author(s): 長谷川卓, 外山浩太郎, O’Connor, L.K.,Huber, B.T.,Hobbs, R.W., Bogus, K.A., IODP Exp. 369乗船研究者
  • Organizer: 古生物学会2018年会
• [Presentation] カナダ太平洋沿岸に分布する上部カンパニアン-マーストリヒチアン階に関する有機地球化学的特徴 (2018)
  • Author(s): 吉川亞理紗，長谷川卓，後藤晶子，岩瀬優也，守屋和佳， Haggart, J.
  • Organizer: 古生物学会2018年会
• [Presentation] 南テチス海高緯度域における白亜紀セノマニアン/チューロニアン境界のOAE2:国際深海科学掘削計画(IODP)第369次航海の予察成果 (2018)
  • Author(s): 長谷川卓・外山浩太郎・L.K.O’Connor・R.W.Hobbs・ K.A. Bogu・IODP Exp. 369乗船研究者
  • Organizer: 日本古生物学会2018年会
• [Presentation] ジュラ系／白亜系境界GSSPの設定に向けて：白亜系国際層序学委員会の動向と日本からの貢献 (2017)
  • Author(s): 長谷川卓
  • Organizer: 日本地質学会2017年会
• [Presentation] Stratigraphic potential of radiolarians for determining the Jurassic/Cretaceous boundary: evidence from pelagic sequences in the Pacific and Tethys (2017)
  • Author(s): Matsuoka, A.
  • Organizer: 10th International Symposium on the Cretaceous, Vienna, Austria
  • Int'l Joint Research
• [Presentation] チャートシーケンスの炭素同位体比層序構築を目指した超微量有機炭素の同位体比分析法の検討 (2016)
  • Author(s): 長谷川卓
  • Organizer: 日本地質学会 第123年学術大会
  • Place of Presentation: 東京都 日本大学
  • Year and Date: 2016-09-10
  • Invited
• [Presentation] Syndepositional formation of calcareous nodules on muddy sea floor: elucidating depositional history by C, O, S isotope characterization (2016)
  • Author(s): Hasegawa, T. and Kobiyama, Y.
  • Organizer: Goldschmidt Conference 2016
  • Place of Presentation: Yokohama, Japan
  • Year and Date: 2016-06-27
  • Int'l Joint Research
• [Presentation] 微量有機炭素・低TOC試料の有機炭素同位体比分析法の検討 (2016)
  • Author(s): 長谷部桂一郎・後藤（桜井）晶子・長谷川卓
  • Organizer: 日本地球惑星科学連合2016年大会
  • Place of Presentation: 幕張メッセ 千葉
  • Year and Date: 2016-05-23