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Takeshi Kakegawa

Section

Graduate School of Science

Job title

Professor

Degree

理学博士（Ph.Ｄ）（ペンシルバニア州立大学）
理学修士（ペンシルバニア州立大学）

researchmap

https://researchmap.jp/KT007181

J-GLOBAL ID

200901090109914166

Research History 2

2010/09 - 2021/06

Tohoku University　Graduate School of Science　Professor
2001/07 - 2010/08

Associate Professor, Tohoku University

Committee Memberships 33

Science Council of Japan　Associate Member

2021/04 - Present
日本掘削科学コンソーシア　ICDP部会委員

2020/04 - Present
JPGU　Associate Editor of PEPS

2018/10 - Present
日本岩石鉱物鉱床学会　編集委員

2000/04 - Present
Geological Society of America　campus representative

1999/10 - Present
JPGU　Executive Committee

2024/06 - 2026/05
Society of Resource Geology　Executive committee

2024/06 - 2026/05
Universiti Malaya　External Revier

2020/08 - 2024/07
JPGU　Section President of Earth-life section

2022/06 - 2024/05
Tohoku University Education and Research Ccouncil　Councilor

2021/04 - 2023/03
Society of Resource Geology　Executive Committee

2020/05 - 2022/05
JPGU　Director

2020/05 - 2022/04
Geochemical Society　Science Committee for Goldschmidt 2022

2021/04 - 2022/03
Japan Society of Origin of life and evolution　Executive Committee

2020/04 - 2022/03
日独先端科学シンポジウム　JSPS専門委員

2016/04 - 2020/03
Geochemical Society　Selection committee

2016/04 - 2017/03
Goldschmidt Conference 2016　セッションコーディネーター

2016/04 - 2017/03
Japan Astrobiology Newwork 仙台大会　LOC

2016/04 - 2017/03
日本地球惑星関連学会　地球生命セクションボードメンバー

2016/04 - 2017/03
日本地球惑星関連学会　連合財務委員

2016/04 - 2017/03
Geochemical Society　Selection committee

2016/04 - 2017/03
Goldschmidt Conference 2016　セッションコーディネーター

2016/04 - 2017/03
Japan Astrobiology Newwork 仙台大会　LOC

2016/04 - 2017/03
日本地球惑星関連学会　地球生命セクションボードメンバー

2016/04 - 2017/03
日本岩石鉱物鉱床学会　編集委員

2016/04 - 2017/03
Geochemical Society　Selection Committee

2016/04 - 2016/12
Geochemical Society　Selection Committee

2016/04 - 2016/12
日本地球惑星連合　代議委員

2011/04 - 2016/03
日本地球惑星連合　代議委員

2011/04 - 2016/03
Geochemical Society　会長選考委員

2012/04 - 2015/06
Geochemical Society　会長選考委員

2012/04 - 2015/06
日本地球惑星連合　代議委員

2011/04 - 2012/03
Integrated Ocean Drilling Program　Science Planning Group Member

2009/12 - 2011/12

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Professional Memberships 8

The Honor Society Phi Kappa Phi
生命の起源と進化学会
日本地球化学会
資源地質学会
日本岩石鉱物鉱床学会
Geochemical Society
Geological Society of America
American Geophysical Union

︎Show all ︎Show first 5

Research Interests 5

Microbial life in extreme environment
stable isotopes
submarine hydrothermal activity
eraly Earth
origin of life

Research Areas 3

Natural sciences / Solid earth science / Geology
Natural sciences / Space and planetary science / Geochemistry
Natural sciences / Solid earth science / Petrology

Awards 3

Charles Holler Alumni Scholar Medal

2024/09　Pennsylvania State University
Almuni Fellow

2021/06　Pennsylvania State University
Phi Kappa Phi Fellow

1992/02　Phi Kappa Phi　優秀学生賞

Papers 169

Archaean green-light environments drove the evolution of cyanobacteria’s light-harvesting system

Taro Matsuo, Kumiko Ito-Miwa, Yosuke Hoshino, Yuri I. Fujii, Satomi Kanno, Kazuhiro J. Fujimoto, Rio Tsuji, Shinnosuke Takeda, Chieko Onami, Chihiro Arai, Yoko Yoshiyama, Yoshihisa Mino, Yuki Kato, Takeshi Yanai, Yuichi Fujita, Shinji Masuda, Takeshi Kakegawa, Hideaki Miyashita

Nature Ecology & Evolution　2025/02/18
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s41559-025-02637-3 　

eISSN： 2397-334X

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Abstract Cyanobacteria induced the great oxidation event around 2.4 billion years ago, probably triggering the rise in aerobic biodiversity. While chlorophylls are universal pigments used by all phototrophic organisms, cyanobacteria use additional pigments called phycobilins for their light-harvesting antennas—phycobilisomes—to absorb light energy at complementary wavelengths to chlorophylls. Nonetheless, an enigma persists: why did cyanobacteria need phycobilisomes? Here, we demonstrate through numerical simulations that the underwater light spectrum during the Archaean era was probably predominantly green owing to oxidized Fe(III) precipitation. The green-light environments, probably shaped by photosynthetic organisms, may have directed their own photosynthetic evolution. Genetic engineering of extant cyanobacteria, simulating past natural selection, suggests that cyanobacteria that acquired a green-specialized phycobilin called phycoerythrobilin could have flourished under green-light environments. Phylogenetic analyses indicate that the common ancestor of modern cyanobacteria embraced all key components of phycobilisomes to establish an intricate energy transfer mechanism towards chlorophylls using green light and thus gained strong selective advantage under green-light conditions. Our findings highlight the co-evolutionary relationship between oxygenic phototrophs and light environments that defined the aquatic landscape of the Archaean Earth and envision the green colour as a sign of the distinct evolutionary stage of inhabited planets.
One-pot synthesis of non-canonical ribonucleosides and their precursors from aldehydes and ammonia under prebiotic Earth conditions

Yuta Hirakawa, Hidenori Okamura, Fumi Nagatsugi, Takeshi Kakegawa, Yoshihiro Furukawa

Geochimica et Cosmochimica Acta　2024/11
Publisher: Elsevier BV
DOI： 10.1016/j.gca.2024.11.006 　

ISSN： 0016-7037
Primary Fe isotope signatures record oxidative precipitation in 3.2 Ga ferruginous siliciclastic sedimentary rocks deposited in a shallow ocean environment

Ryohei Suzumeji, Tsubasa Otake, Daizo Yamauchi, Yoko Ohtomo, Takeshi Kakegawa, Christoph Heubeck, Shin ichi Yamasaki, Tsutomu Sato

Precambrian Research　413　2024/10

DOI： 10.1016/j.precamres.2024.107574 　

ISSN： 0301-9268
Ultrahigh-resolution imaging of biogenic phosphorus and molybdenum in palaeoproterozoic gunflint microfossils

Kohei Sasaki, Akizumi Ishida, Takeshi Kakegawa, Naoto Takahata, Yuji Sano

Scientific Reports　14　(1)　2024/09/20
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s41598-024-72191-8 　

eISSN： 2045-2322
BASE (Barberton Archean Surface Environments) – drilling Paleoarchean coastal strata of the Barberton Greenstone Belt

Christoph Heubeck, Nic Beukes, Michiel de Kock, Martin Homann, Emmanuelle J. Javaux, Takeshi Kakegawa, Stefan Lalonde, Paul Mason, Phumelele Mashele, Dora Paprika, Chris Rippon, Mike Tice, Rodney Tucker, Ryan Tucker, Victor Ndazamo, Astrid Christianson, Cindy Kunkel

Scientific Drilling　2024/06/18

DOI： 10.5194/sd-33-129-2024 　
Hexose phosphorylation for a non-enzymatic glycolysis and pentose phosphate pathway on early Earth

Yuta Hirakawa, Takeshi Kakegawa, Yoshihiro Furukawa

Scientific Reports　14　(1)　2024/01/02
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s41598-023-50743-8 　

eISSN： 2045-2322

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Abstract Glycolysis and pentose phosphate pathways play essential roles in cellular processes and are assumed to be among the most ancient metabolic pathways. Non-enzymatic metabolism-like reactions might have occurred on the prebiotic Earth and been inherited by the biological reactions. Previous research has identified a part of the non-enzymatic glycolysis and the non-enzymatic pentose phosphate pathway from glucose 6-phosphate and 6-phosphogluconate, which are intermediates of these reactions. However, how these phosphorylated molecules were formed on the prebiotic Earth remains unclear. Herein, we demonstrate the synthesis of glucose and gluconate from simple aldehydes in alkaline solutions and the formation of glucose 6-phosphate and 6-phosphogluconate with borate using thermal evaporation. These results imply that the initial stages of glycolysis-like and pentose phosphate pathway-like reactions were achieved in borate-rich evaporative environments on prebiotic Earth, suggesting that non-enzymatic metabolism provided biomolecules and their precursors on prebiotic Earth.
Abiotic formation of glycine-alanine peptides in alkaline evaporative environments

Jonathan Stimmer, Takeshi Kakegawa, Yoshihiro Furukawa

GEOCHEMICAL JOURNAL　2024

DOI： 10.2343/geochemj.GJ24018 　
Abiotic Ribose Synthesis Under Aqueous Environments with Various Chemical Conditions

Chinatsu Ono, Sako Sunami, Yuka Ishii, Hyo Joong Kim, Takeshi Kakegawa, Steven A. Benner, Yoshihiro Furukawa

Astrobiology　2024

DOI： 10.1089/ast.2023.0071 　

ISSN： 1531-1074
Boron-assisted abiotic polypeptide synthesis. International-journal

Yuki Sumie, Keiichiro Sato, Takeshi Kakegawa, Yoshihiro Furukawa

Communications chemistry　6　(1)　89-89　2023/05/11

DOI： 10.1038/s42004-023-00885-7 　

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The emergence of proteins and their interactions with RNAs were a key step in the origin and early evolution of life. The abiotic synthesis of peptides has been limited in short amino acid length and is favored in highly alkaline evaporitic conditions in which RNAs are unstable. This environment is also inconsistent with estimated Hadean Earth. Prebiotic environments rich in boron are reportedly ideal for abiotic RNA synthesis. However, the effects of boron on amino acid polymerization are unclear. We report that boric acid enables the polymerization of amino acids at acidic and near-neutral pH levels based on simple heating experiments of amino acid solutions containing borate/boric acid at various pH levels. Our study provides evidence for the boron-assisted synthesis of polypeptides in prebiotically plausible environments, where the same conditions would allow for the formation of RNAs and interactions of primordial proteins and RNAs that could be inherited by RNA-dependent protein synthesis during the evolution of life.
Abiotic formation of ribose 5'-phosphate from ribose and apatite with carbonate- and formate-rich solutions

Masaya Takabayashi, Yuta Hirakawa, Takeshi Kakegawa, Yoshihiro Furukawa

GEOCHEMICAL JOURNAL　57　(5)　134-142　2023
Publisher: Geochemical Society of Japan
DOI： 10.2343/geochemj.gj23012 　

ISSN： 0016-7002

eISSN： 1880-5973
Borate-guided ribose phosphorylation for prebiotic nucleotide synthesis

Yuta Hirakawa, Takeshi Kakegawa, Yoshihiro Furukawa

Scientific Reports　12　(1)　2022/12

DOI： 10.1038/s41598-022-15753-y 　

ISSN： 2045-2322
Evolutionary diversification of paleoproterozoic prokaryotes: New microfossil records in 1.88 Ga Gunflint Formation

Kohei Sasaki, Akizumi Ishida, Naoto Takahata, Yuji Sano, Takeshi Kakegawa

Precambrian Research　380　2022/09/15

DOI： 10.1016/j.precamres.2022.106798 　

ISSN： 0301-9268
Mineralogical and Genomic Constraints on the Origin of Microbial Mn Oxide Formation in Complexed Microbial Community at the Terrestrial Hot Spring

Yuya Tsukamoto, Takeshi Kakegawa

Life　12　(6)　816-816　2022/05/30
Publisher: MDPI AG
DOI： 10.3390/life12060816 　

eISSN： 2075-1729

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Manganese (Mn) oxides are widespread on the surface environments of the modern Earth. The role of microbial activities in the formation of Mn oxides has been discussed for several decades. However, the mechanisms of microbial Mn oxidation, and its role in complex microbial communities in natural environments, remain uncertain. Here, we report the geochemical, mineralogical, and metagenomic evidence for biogenic Mn oxides, found in Japanese hot spring sinters. The low crystallinity of Mn oxides, and their spatial associations with organic matter, support the biogenic origin of Mn oxides. Specific multicopper oxidases (MCOs), which are considered Mn-oxidizing enzymes, were identified using metagenomic analyses. Nanoscale nuggets of copper sulfides were, also, discovered in the organic matter in Mn-rich sinters. A part of these copper sulfides most likely represents traces of MCOs, and this is the first report of traces of Mn-oxidizing enzyme in geological samples. Metagenomic analyses, surprisingly, indicated a close association of Mn oxides, not only in aerobic but also in anaerobic microbial communities. These new findings offer the unique and unified positions of Mn oxides, with roles that have not been ignored, to sustain anaerobic microbial communities in hot spring environments.
Complex history of aerobic respiration and phototrophy in the chloroflexota class anaerolineae revealed by high-quality draft genome of ca. Roseilinea mizusawaensis aa3_104

Lewis M. Ward, Fátima Li-Hau, Takeshi Kakegawa, Shawn E. McGlynn

Microbes and Environments　36　(3)　2021/07/01
Publisher: Japanese Society of Microbial Ecology
DOI： 10.1264/jsme2.ME21020 　

ISSN： 1347-4405 1342-6311
Experimental Investigation of the Formation of Formaldehyde by Hadean and Noachian Impacts

Saeka Masuda, Yoshihiro Furukawa, Takamichi Kobayashi, Toshimori Sekine, Takeshi Kakegawa

Astrobiology　21　(4)　413-420　2021/04

DOI： 10.1089/ast.2020.2320 　

ISSN： 1531-1074

eISSN： 1557-8070
Impact-induced amino acid formation on Hadean Earth and Noachian Mars

Yuto Takeuchi, Yoshihiro Furukawa, Takamichi Kobayashi, Toshimori Sekine, Naoki Terada, Takeshi Kakegawa

Scientific Reports　10　(1)　2020/12/01

DOI： 10.1038/s41598-020-66112-8 　

ISSN： 2045-2322

eISSN： 2045-2322
Geochemical and mineralogical studies of ca.12 Ma hydrothermal manganese-rich rocks in the Hokuroku district in Japan

Yuya Tsukamoto, Kenta Nonaka, Akizumi Ishida, Takeshi Kakegawa

Ore Geology Reviews　121　2020/06

DOI： 10.1016/j.oregeorev.2020.103539 　

ISSN： 0169-1368

eISSN： 1872-7360
Vestiges of adaptation to the mesophilic environment in the genome of tepiditoga spiralis gen. Nov., sp. nov.

Koji Mori, Kenta Sakurai, Akira Hosoyama, Takeshi Kakegawa, Satoshi Hanada

Microbes and Environments　35　(4)　1-8　2020

DOI： 10.1264/jsme2.ME20046 　

ISSN： 1342-6311

eISSN： 1347-4405
Biogenic and abiogenic graphite in minerals and rocks of the early earth

Takeshi Kakegawa

Astrobiology: From the Origins of Life to the Search for Extraterrestrial Intelligence　209-227　2019/01/01

DOI： 10.1007/978-981-13-3639-3_15 　
Simultaneous In Situ Analysis of Carbon and Nitrogen Isotope Ratios in Organic Matter by Secondary Ion Mass Spectrometry Peer-reviewed

Akizumi Ishida, Kouki Kitajima, Kenneth H. Williford, Michael L. Tuite, Takeshi Kakegawa, John W. Valley

Geostandards and Geoanalytical Research　42　(2)　189-203　2018/06

DOI： 10.1111/ggr.12209 　

ISSN： 1639-4488

eISSN： 1751-908X
Racemization of Valine by Impact-Induced Heating Peer-reviewed

Yoshihiro Furukawa, Atsushi Takase, Toshimori Sekine, Takeshi Kakegawa, Takamichi Kobayashi

Origins of Life and Evolution of Biospheres　48　(1)　131-139　2018/03/01

DOI： 10.1007/s11084-017-9539-0 　

ISSN： 0169-6149

eISSN： 1573-0875
Microbial diversity and iron oxidation at Okuoku-hachikurou Onsen, a Japanese hot spring analog of Precambrian iron formations Peer-reviewed

L. M. Ward, A. Idei, S. Terajima, T. Kakegawa, W. W. Fischer, S. E. McGlynn

Geobiology　15　(6)　817-835　2017/11

DOI： 10.1111/gbi.12266 　

ISSN： 1472-4677

eISSN： 1472-4669
Borate and the origin of RNA: A Model for the Precursors to Life Peer-reviewed

Yoshihiro Furukawa, Takeshi Kakegawa

Elements　13　(4)　261-265　2017/08

DOI： 10.2138/gselements.13.4.261 　

ISSN： 1811-5209

eISSN： 1811-5217
Effects of Glycine, Water, Ammonia, and Ammonium Bicarbonate on the Oligomerization of Methionine Peer-reviewed

Rui Huang, Yoshihiro Furukawa, Tsubasa Otake, Takeshi Kakegawa

Origins of Life and Evolution of Biospheres　47　(2)　145-160　2017/06/01

DOI： 10.1007/s11084-016-9518-x 　

ISSN： 0169-6149

eISSN： 1573-0875
Morphological changes of olivine grains reacted with amino acid solutions by impact process Peer-reviewed

Yuhei Umeda, Atsushi Takase, Nao Fukunaga, Toshimori Sekine, Takamichi Kobayashi, Yoshihiro Furukawa, Takeshi Kakegawa

Physics and Chemistry of Minerals　44　(3)　203-212　2017/03/01

DOI： 10.1007/s00269-016-0849-y 　

ISSN： 0342-1791

eISSN： 1432-2021
Microstructure and geochemistry of organic matters in banded iron formations, Moodies Group, Barberton Green stone Belt, South Africa

Nakajima Ryo, Ohtomo Yoko, Otake Tsubasa, Kakegawa Takeshi, Sato Tsutomu

Abstracts of Annual Meeting of the Geochemical Society of Japan　64　308-308　2017
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.64.0_308 　

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stabilization of ribose by kaolinite

Nitta Ayumi, Furukawa Yoshihiro, Kakegawa Takeshi

Abstracts of Annual Meeting of the Geochemical Society of Japan　64　306-306　2017
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.64.0_306 　

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Micro to nanoscale observations of carbonaceous matters in Archaean sedimentary rocks : Examples of > 3.7 Ga Isua Supracrustal Belt and 3.2 Ga banded iron formations, Moodies Group, Barberton Greensto

Ohtomo Yoko, Nakajima Ryo, Otake Tsubasa, Kakegawa Takeshi

Abstracts of Annual Meeting of the Geochemical Society of Japan　64　166-166　2017
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.64.0_166 　

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Effects of ammonia on organic synthesis through impacts of meteorites on the early ocean

Takeuchi Yuto, Furukawa Yoshihiro, Kobayashi Takamichi, Sekine Toshimori, Kakegawa Takeshi

Abstracts of Annual Meeting of the Geochemical Society of Japan　64　300-300　2017
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.64.0_300 　

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Quantitative evaluation of the effects by borate on the formose reaction

Furukawa Yoshihiro, Abe Chiaki, Kakegawa Takeshi

Abstracts of Annual Meeting of the Geochemical Society of Japan　64　304-304　2017
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.64.0_304 　

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Origin and Significance of Mn oxides in the Hokuroku district, Japan

Tsukamoto Yuya, Kakegawa Takeshi

Abstracts of Annual Meeting of the Geochemical Society of Japan　64　149-149　2017
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.64.0_149 　

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Microbial nitrogen cycle enhanced by continental input recorded in the Gunflint Formation Peer-reviewed

A. Ishida, K. Hashizume, T. Kakegawa

Geochemical Perspectives Letters　4　13-18　2017

DOI： 10.7185/geochemlet.1729 　

ISSN： 2410-339X

eISSN： 2410-3403
Evaporite Borate-Containing Mineral Ensembles Make Phosphate Available and Regiospecifically Phosphorylate Ribonucleosides: Borate as a Multifaceted Problem Solver in Prebiotic Chemistry Peer-reviewed

Hyo Joong Kim, Yoshihiro Furukawa, Takeshi Kakegawa, Andrei Bita, Romulus Scorei, Steven A. Benner

Angewandte Chemie - International Edition　55　(51)　15816-15820　2016/12/19

DOI： 10.1002/anie.201608001 　

ISSN： 1433-7851

eISSN： 1521-3773
Occurrence of Tourmaline in Metasedimentary Rocks of the Isua Supracrustal Belt, Greenland: Implications for Ribose Stabilization in Hadean Marine Sediments Peer-reviewed

Shinpei Mishima, Yoko Ohtomo, Takeshi Kakegawa

Origins of Life and Evolution of Biospheres　46　(2-3)　247-271　2016/06/01

DOI： 10.1007/s11084-015-9474-x 　

ISSN： 0169-6149

eISSN： 1573-0875
Effects of Silicate, Phosphate, and Calcium on the Stability of Aldopentoses Peer-reviewed

Sakiko Nitta, Yoshihiro Furukawa, Takeshi Kakegawa

Origins of Life and Evolution of Biospheres　46　(2-3)　189-202　2016/06/01

DOI： 10.1007/s11084-015-9472-z 　

ISSN： 0169-6149

eISSN： 1573-0875
Survivability and reactivity of glycine and alanine in early oceans: effects of meteorite impacts. Peer-reviewed

Umeda,Y, Fukunaga, N, Sekine,T, Furukawa,Y, Kakegawa, T, Kobayashi, T, Nakazawa, H

Journal of Biological Physics　42　177-198　2016/05

DOI： 10.1007/s10867 　
「地球が生命をつくった」仮説の検証ー地球化学と化学の接点. Peer-reviewed

掛川武

化学　71　68-69　2016/05
太古の岩石が語る地球最古の微生物活動ー38〜37億年前の海で生息していたことが明らかに Peer-reviewed

掛川武

生物の科学遺伝　71　(2)　133-138　2016/05
Publisher:
ISSN： 0387-0022
Survivability and reactivity of glycine and alanine in early oceans: effects of meteorite impacts Peer-reviewed

Yuhei Umeda, Nao Fukunaga, Toshimori Sekine, Yoshihiro Furukawa, Takeshi Kakegawa, Takamichi Kobayashi, Hiromoto Nakazawa

Journal of Biological Physics　42　(1)　177-198　2016/01/01

DOI： 10.1007/s10867-015-9400-5 　

ISSN： 0092-0606

eISSN： 1573-0689
Nucleobase and amino acid formation through impacts of meteorites on the early ocean Peer-reviewed

Yoshihiro Furukawa, Hiromoto Nakazawa, Toshimori Sekine, Takamichi Kobayashi, Takeshi Kakegawa

Earth and Planetary Science Letters　429　216-222　2015/11/01

DOI： 10.1016/j.epsl.2015.07.049 　

ISSN： 0012-821X

eISSN： 1385-013X
Shock wave synthesis of amino acids from solutions of ammonium formate and ammonium bicarbonate Peer-reviewed

Chizuka Suzuki, Yoshihiro Furukawa, Takamichi Kobayashi, Toshimori Sekine, Hiromoto Nakazawa, Takeshi Kakegawa

Geochemistry, Geophysics, Geosystems　16　(7)　2382-2394　2015/07/01

DOI： 10.1002/2015GC005783 　

ISSN： 1525-2027

eISSN： 1525-2027
東北地方太平洋江沖地震による岩手、宮城、福島県沿岸域における津波堆積物の供給源 Peer-reviewed

奈良郁子, 渡邊隆広, 掛川武, 山崎慎一, 井上千弘, 土谷範芳

地学雑誌　123　(6)　871-882　2014/08
Publisher: Tokyo Geographical Society
DOI： 10.5026/jgeography.123.871 　

ISSN： 0022-135X

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Geochemical analyses (total nitrogen: TN, total organic carbon: TOC, total sulfur: TS, and stable sulfur isotope ratio: δ³⁴S) were performed on tsunami deposits by the 2011 off the Pacific coast of Tohoku Earthquake obtained from Iwate, Minamisanriku, Kesen-numa, and Sendai Bay areas for a total of 133 samples. Although TOC/TN ratios ranged widely (0.7–90), most of the samples (more than 80% of samples) ranged from 10–30, which were similar results to those for marine surface sediment in the Pacific coast area. Low δ³⁴S values (from -29.6‰ to -11.3‰) from Iwate, Minami Sanriku, and Sendai Bay tsunami deposits were observed. Generally, such low δ³⁴S values result from large isotope fractionation caused by the activity of sulfate-reducing bacteria in marine sediment under a sulfate (SO₄^2-) rich environment. These results suggest that the tsunami deposits were mainly derived from marine sediment. High correlations between TS and As contents (r=0.958) were observed in tsunami deposits from the Kesen-numa area. Furthermore, the high δ³⁴S values (from -3.1‰ to -0.7‰) in the tsunami deposits from the Kesen-numa area correspond well with those of hydrothermal ore samples from the Kesen-numa area. These results indicate that sulfur and arsenic in tsunami deposits from the Kesen-numa area originated in slag from the mines.
Biological nitrate utilization in south Siberian lakes (Baikal and Hovsgol) during the Last Glacial period: The influence of climate change on primary productivity Peer-reviewed

Fumiko Watanabe Nara, Takahiro Watanabe, Takeshi Kakegawa, Koji Minoura, Akio Imai, Nathalie Fagel, Kazuho Horiuchi, Toshio Nakamura, Takayoshi Kawai

Quaternary Science Reviews　90　69-79　2014/04

DOI： 10.1016/j.quascirev.2014.02.014 　

ISSN： 0277-3791
グリーンランドで最古の生命の痕跡を発見

掛川武

化学と工業　2014/04
グリーンランドで発見された最古の生物活動の痕跡 Invited Peer-reviewed

掛川武

Isotope News　2014/04
Experimental investigation of reduced volatile formation by high-temperature interactions among meteorite constituent materials, water, and nitrogen Peer-reviewed

Yoshihiro Furukawa, Taro Samejima, Hiromoto Nakazawa, Takeshi Kakegawa

ICARUS　231　77-82　2014/03

DOI： 10.1016/j.icarus.2013.11.033 　

ISSN： 0019-1035

eISSN： 1090-2643
Experimental investigation of reduced volatile formation by high-temperature interactions among meteorite constituent materials, water, and nitrogen Peer-reviewed

Yoshihiro Furukawa, Taro Samejima, Hiromoto Nakazawa, Takeshi Kakegawa

Icarus　231　77-82　2014/03/01

DOI： 10.1016/j.icarus.2013.11.033 　

ISSN： 0019-1035

eISSN： 1090-2643
Spatial distributions of chromium enrichment in ~3.2 Ga Banded Iron Formations, Barberton Greenstone Belt, South Africa

ISHIKAWA KO, OTAKE TSUBASA, KAWAI SHOHJI, SATO TSUTOMU, KAKEGAWA TAKESHI

Abstracts of Annual Meeting of the Geochemical Society of Japan　61　127-127　2014
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.61.0_127 　
Evidence for biogenic graphite in early archaean isua metasedimentary rocks Peer-reviewed

Yoko Ohtomo, Takeshi Kakegawa, Akizumi Ishida, Toshiro Nagase, Minik T. Rosing

Nature Geoscience　7　(1)　25-28　2014

DOI： 10.1038/ngeo2025 　

ISSN： 1752-0894

eISSN： 1752-0908
Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks Peer-reviewed

Ohtomo Yoko, Kakegawa Takeshi, Ishida Akizumi, Nagase Toshiro, Rosing Minik T

NATURE GEOSCIENCE　7　(1)　25-28　2014/01

DOI： 10.1038/ngeo2025 　

ISSN： 1752-0894
Selective Stabilization of Ribose by Borate Peer-reviewed

Yoshihiro Furukawa, Mana Horiuchi, Takeshi Kakegawa

Origins of Life and Evolution of Biospheres　43　(4-5)　353-361　2013/10

DOI： 10.1007/s11084-013-9350-5 　

ISSN： 0169-6149

eISSN： 1573-0875
Sulfur isotope profiles in the pelagic Panthalassic deep sea during the Permian-Triassic transition Peer-reviewed

Satoshi Takahashi, Kunio Kaiho, Rie S. Hori, Paul Gorjan, Takahiro Watanabe, Satoshi Yamakita, Yoshiaki Aita, Atsushi Takemura, K. Bernhard Spörli, Takeshi Kakegawa, Masahiro Oba

Global and Planetary Change　105　68-78　2013/06

DOI： 10.1016/j.gloplacha.2012.12.006 　

ISSN： 0921-8181
A chronology of the PY608E-PC sediment core (Lake Pumoyum Co, southern Tibetan Plateau) based on radiocarbon dating of total organic carbon Peer-reviewed

Takahiro Watanabe, Toshio Nakamura, Tetsuya Matsunaka, Fumiko Watanabe Nara, Liping Zhu, Junbo Wang, Takeshi Kakegawa, Mitsugu Nishimura

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms　294　520-523　2013/01

DOI： 10.1016/j.nimb.2012.07.015 　

ISSN： 0168-583X
Abiotic Formation of Valine Peptides Under Conditions of High Temperature and High Pressure Peer-reviewed

Yoshihiro Furukawa, Tsubasa Otake, Takato Ishiguro, Hiromoto Nakazawa, Takeshi Kakegawa

Origins of Life and Evolution of Biospheres　42　(6)　519-531　2012/12

DOI： 10.1007/s11084-012-9295-0 　

ISSN： 0169-6149

eISSN： 1573-0875
Last glacial to post glacial climate changes in continental Asia inferred from multi-proxy records (geochemistry, clay mineralogy, and paleontology) from Lake Hovsgol, northwest Mongolia Peer-reviewed

Takahiro Watanabe, Koji Minoura, Fumiko Watanabe Nara, Koji Shichi, Kazuho Horiuchi, Takeshi Kakegawa, Takayoshi Kawai

Global and Planetary Change　88-89　53-63　2012/05

DOI： 10.1016/j.gloplacha.2012.03.005 　

ISSN： 0921-8181

eISSN： 1872-6364
Stepwise combustion analyses of distinct nitrogen isotopic compositions on Paleoproterozoic organic matter Peer-reviewed

Akizumi Ishida, Ko Hashizume, Takeshi Kakegawa

Geochemical Journal　46　(3)　249-253　2012

DOI： 10.2343/geochemj.1.0165 　

ISSN： 0016-7002

eISSN： 1880-5973
Gunflint Formation Peer-reviewed

Kakegawa T, Ishida A

Encyclopedia of Astrobiology　2011/11
Impact-induced phyllosilicate formation from olivine and water Peer-reviewed

Yoshihiro Furukawa, Toshimori Sekine, Takeshi Kakegawa, Hiromoto Nakazawa

GEOCHIMICA ET COSMOCHIMICA ACTA　75　(21)　6461-6472　2011/11

DOI： 10.1016/j.gca.2011.08.029 　

ISSN： 0016-7037

eISSN： 1872-9533
Impact-induced phyllosilicate formation from olivine and water Peer-reviewed

Yoshihiro Furukawa, Toshimori Sekine, Takeshi Kakegawa, Hiromoto Nakazawa

Geochimica et Cosmochimica Acta　75　(21)　6461-6472　2011/11/01

DOI： 10.1016/j.gca.2011.08.029 　

ISSN： 0016-7037

eISSN： 1872-9533
Stability of amino acids and their oligomerization under high-pressure conditions: Implications for prebiotic chemistry Peer-reviewed

Tsubasa Otake, Takashi Taniguchi, Yoshihiro Furukawa, Fumio Kawamura, Hiromoto Nakazawa, Takeshi Kakegawa

Astrobiology　11　(8)　799-813　2011/10/01

DOI： 10.1089/ast.2011.0637 　

ISSN： 1531-1074
Stability of Amino Acids and Their Oligomerization Under High-Pressure Conditions: Implications for Prebiotic Chemistry Peer-reviewed

Tsubasa Otake, Takashi Taniguchi, Yoshihiro Furukawa, Fumio Kawamura, Hiromoto Nakazawa, Takeshi Kakegawa

ASTROBIOLOGY　11　(8)　799-813　2011/10

DOI： 10.1089/ast.2011.0637 　

ISSN： 1531-1074

eISSN： 1557-8070
Geological and geochemical study of Archean sedimentary rocks of the 3.0 Ga Lumby Lake Group, Canada

Yokota Kazuya, Kakegawa Takeshi

Abstracts of Annual Meeting of the Geochemical Society of Japan　58　60-60　2011
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.58.0.60.0 　
Sedimentary environments after 15 to 10 Ma Kuroko deposits in the Hokuroku basin: mineralogical and geochemical studies on framboidal pyrite

Endo Misato, Yamada Ryoichi, Otake Tsubasa, Kakegawa Takeshi

Abstracts of Annual Meeting of the Geochemical Society of Japan　58　95-95　2011
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.58.0.95.0 　
Effects of pressure on the oligomerization of valine

Furukawa Yoshihiro, Otake Tsubasa, Nakazawa Hiromoto, Kakegawa Takeshi

Abstracts of Annual Meeting of the Geochemical Society of Japan　58　55-55　2011
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.58.0.55.0 　
Carbon and nitrogen stable isotopic compositions of kerogen associated with kuroko deposits in the Hokuriku district, Akita.

Nakahata Yoshitsugu, Yamada Ryoichi, Takeshi Kakegawa

Abstracts of Annual Meeting of the Geochemical Society of Japan　58　127-127　2011
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.58.0.127.0 　
Effects of borate on ribose formation on the early Earth

Horiuchi Mana, Furukawa Yoshihiro, Kakegawa Takashi

Abstracts of Annual Meeting of the Geochemical Society of Japan　58　121-121　2011
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.58.0.121.0 　
Stability of amino acids and their oligomerization under high temperature and high pressure conditions

Otake Tsubasa, Taniguchi Takashi, Furukawa Yoshihiro, Nakazawa Hiromoto, Kakegawa Takeshi

Abstracts of Annual Meeting of the Geochemical Society of Japan　58　120-120　2011
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.58.0.120.0 　
Origins of magnetite and chromite in 3.2 Ga chemical and clastic sedimentary rocks in the Barberton greenstone belt, South Africa

Sakamoto Yuki, Kakegawa Takeshi, Otake Tsubasa

Abstracts of Annual Meeting of the Geochemical Society of Japan　58　124-124　2011
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.58.0.124.0 　
Reconstruction of palaeo-environmental variations during the end-Permian mass extinction and its aftermath at the pelagic super-ocean Peer-reviewed

Takahashi Satoshi, Tsuchiya Noriyoshi, Yohida Takeyoshi, Sakata Susumu, Suzuki Noritoshi, Ehiro Masayuki, Kaiho Kunio, Yamakita Satoshi, Oba Masahiro, Kakegawa Takeshi, Watanabe Takahiro, Yamasaki Shin-ichi, Ogawa Yasumasa, Kimura Kazuhiko

Abstracts of Annual Meeting of the Geochemical Society of Japan　58　(0)　86-86　2011
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.58.0.86.0 　
Climate control of sulfate influx to Lake Hovsgol, northwest Mongolia, during the last glacial-postglacial transition: Constraints from sulfur geochemistry Peer-reviewed

Fumiko Watanabe Nara, Takahiro Watanabe, Takeshi Kakegawa, Haruhiko Seyama, Kazuho Horiuchi, Toshio Nakamura, Akio Imai, Nobuyuki Kawasaki, Takayoshi Kawai

Palaeogeography, Palaeoclimatology, Palaeoecology　298　(3-4)　278-285　2010/12/15

DOI： 10.1016/j.palaeo.2010.10.001 　

ISSN： 0031-0182
Climate control of sulfate influx to Lake Hovsgol, northwest Mongolia, during the last glacial-postglacial transition: Constraints from sulfur geochemistry Peer-reviewed

Fumiko Watanabe Nara, Takahiro Watanabe, Takeshi Kakegawa, Haruhiko Seyama, Kazuho Horiuchi, Toshio Nakamura, Akio Imai, Nobuyuki Kawasaki, Takayoshi Kawai

PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY　298　(3-4)　278-285　2010/12

DOI： 10.1016/j.palaeo.2010.10.001 　

ISSN： 0031-0182

eISSN： 1872-616X
Last glacial-Holocene geochronology of sediment cores from a high-altitude Tibetan lake based on AMS ¹⁴C dating of plant fossils: Implications for paleoenvironmental reconstructions Peer-reviewed

Takahiro Watanabe, Tetsuya Matsunaka, Toshio Nakamura, Mitsugu Nishimura, Yasuhiro Izutsu, Motoyasu Minami, Fumiko Watanabe Nara, Takeshi Kakegawa, Junbo Wang, Liping Zhu

Chemical Geology　277　(1-2)　21-29　2010/10

DOI： 10.1016/j.chemgeo.2010.07.004 　

ISSN： 0009-2541

eISSN： 1872-6836
東北地方北部の金属鉱床に随伴する高インジウム鉱石の形成条件 Peer-reviewed

山田亮一, 吉田武義, 掛川武, 奈良郁子, 小川泰正

資源地質　60　(3)　153-164　2010/09/01
Publisher: The Society of Resource Geology
DOI： 10.11456/shigenchishitsu.60.153 　

ISSN： 0918-2454

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High-indium ore deposits are associated within the rise tectonic zones of progressive rift-rise structures resulted from the late Cenozoic back-arc spreading of the northern Honshu arc. We examined the indium concentration mechanism around the Hokuroku district, which constitutes one of the typical rift-rise settings. The Tatsumata mine area in the SE wing of the Hokuroku rift comprises three segments of base-metal vein system which is thought to be xenothermal type related to gabbroic to dioritic stocks emplaced at ca. 17 Ma. Almost all the specimens taken from stock piles of the ores have high indium contents ranged from several tens to 400ppm, correlated with tin, bismuth and cobalt contents. The vein system is composed of two different mineralization stages; chalcopyrite-pyrite veins with subordinate pyrrhotite, magnetite and rare sphalerite, and the following sphalerite-dominant veins with subordinate galena and a few manganese minerals. Indium is contained in the both stage mineralizations. It is concentrated only in the marginal part of the sphalerite crystal with chalcopyrite exsolution blebs, although it has no obvious correlation with Zn and Cu contents. Sulfur isotopes indicate two different series of the hydrothermal activity. The first is characterized by relatively low δ³⁴S values which exists in the gabbroic stocks, the lower unit silicified rocks and the early stage veins. This series was suggested to be formed dominantly from a magmatic hydrothermal solution with relatively reducing condition. Another series has relatively heavy δ³⁴S values and occurs in the diorite porphyry stocks, the upper unit silicified zones and the later stage veins. This series was suggested to be formed by a relatively oxidized hydrothermal solution originated by mixing with sea water. Indium may have been released in the early stage hydrothermal fluid with tin, bismuth and cobalt and was involved in sphalerite crystal, probably replaced to iron, of the late stage mineralization. In consideration of the stratigraphic position and the mineralization timing in the tectonic history of the northern Honshu arc, it was suggested that the mineralization environment changed from a terrestrial rise setting in which magmatic emanation was predominant from a deep seated magma chamber to a rift wing setting in which brine water was circulating along a fracture system formed by rapid rifting of the adjacent area. The drastic redox condition change of the ore-forming solution in conjunction with the rapid tectonic change should be important for the indium concentration.
Radiocarbon and stable carbon isotope ratio data from a 4.7-mlong sediment core of Lake Baikal (Southern Siberia, Russia) Peer-reviewed

Fumiko Watanabe Nara, Takahiro Watanabe, Toshio Nakamura, Takeshi Kakegawa, Fumitaka Katamura, Koji Shichi, Hikaru Takahara, Akio Imai, Takayoshi Kawai

Radiocarbon　52　(3)　1449-1457　2010/08

DOI： 10.1017/S0033822200046531 　

ISSN： 0033-8222

eISSN： 1945-5755
¹⁴C dating of holocene soils from an island in lake pumoyum co (Southeastern Tibetan Plateau) Peer-reviewed

Takahiro Watanabe, Tetsuya Matsunaka, Toshio Nakamura, Mitsugu Nishimura, Takahiro Sakai, Xiao Lin, Kazuho Horiuchi, Fumiko Watanabe Nara, Takeshi Kakegawa, Liping Zhu

Radiocarbon　52　(3)　1443-1448　2010/08

DOI： 10.1017/S003382220004652X 　

ISSN： 0033-8222
A new ¹⁴C data set of the PY608W-PC sediment core from lake pumoyum co (Southeastern Tibetan Plateau) over the last 19 KYR Peer-reviewed

Takahiro Watanabe, Tetsuya Matsunaka, Toshio Nakamura, Mitsugu Nishimura, Yasuhiro Izutsu, Motoyasu Minami, Fumiko Watanabe Nara, Takeshi Kakegawa, Liping Zhu

Radiocarbon　52　(3)　1435-1442　2010/08

DOI： 10.1017/S0033822200046518 　

ISSN： 0033-8222
A smooth negative shift of organic-carbon isotope ratios at an end-Permian mass extinction horizon in central pelagic Panthalassa Peer-reviewed

Satoshi Takahashi, Kunio Kaiho, Masahiro Oba, Takeshi Kakegawa

Journal of Earth Science　21　(SUPPL. 1)　165-166　2010/06

DOI： 10.1007/s12583-010-0200-3 　

ISSN： 1674-487X

eISSN： 1867-111X
Biogeography and biodiversity in sulfide structures of active and inactive vents at deep-sea hydrothermal fields of the southern mariana trough Peer-reviewed

Shingo Kato, Yoshinori Takano, Takeshi Kakegawa, Hironori Oba, Kazuhiko Inoue, Chiyori Kobayashi, Motoo Utsumi, Katsumi Marumo, Kensei Kobayashi, Yuki Ito, Jun Ichiro Ishibashi, Akihiko Yamagishi

Applied and Environmental Microbiology　76　(9)　2968-2979　2010/05

DOI： 10.1128/AEM.00478-10 　

ISSN： 0099-2240

eISSN： 1098-5336
delta C-13-delta D distribution of lipid biomarkers in a bacterial mat from a hot spring in Miyagi Prefecture, NE Japan Peer-reviewed

Hiroshi Naraoka, Tomoko Uehara, Satoshi Hanada, Takeshi Kakegawa

ORGANIC GEOCHEMISTRY　41　(4)　398-403　2010/04

DOI： 10.1016/j.orggeochem.2009.11.008 　

ISSN： 0146-6380
Changes of organic matter sources in sediment cores from a high-altitude lake (Pumoyum Co, southeastern Tibetan plateau) over the last 19,000 years Peer-reviewed

Takahiro Watanabe, Tetsuya Matsunaka, Toshio Nakamura, Mitsugu Nishimura, Fumiko Watanabe Nara, Takeshi Kakegawa, Liping Zhu

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms　268　(7-8)　1070-1072　2010/04

DOI： 10.1016/j.nimb.2009.10.100 　

ISSN： 0168-583X
δ¹³C-δD distribution of lipid biomarkers in a bacterial mat from a hot spring in Miyagi Prefecture, NE Japan Peer-reviewed

Hiroshi Naraoka, Tomoko Uehara, Satoshi Hanada, Takeshi Kakegawa

Organic Geochemistry　41　(4)　398-403　2010/04

DOI： 10.1016/j.orggeochem.2009.11.008 　

ISSN： 0146-6380
Role of the Archean submarine hydrothermal activities on evolution of the early biosphere: Report from massive sulfide ores at Sulfur Springs in Pilbara, Australia Peer-reviewed

Takeshi Kakegawa

Viva Origino　38　(1)　29-34　2010/03/01
Publisher:
ISSN： 0910-4003

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Anciet submarine hydrothermal environments have been considered as important locations where the first life flourished. On the other hand, many experimental results postulate if submarine hydrothermal environments were suitable for the chemical evolution for origin of life. Geological records of Archean submarine hydrothermal ore deposits are present allover the world. Those ore deposits often accompany with carbonaceous sediments, suggesting high microbial activities around the discharging hydrothermal fluids. Such carbonaceous sediments may provide an opportunity to examine evolution of early life in submarine hydrothermal environments. Here I present the evidence of high microbial activities at ca. 3.2-billion-years-old submarine hydrothermal fields of Sulfur Springs in Australia. It is found that examine samples associated with the ore deposit were rich in organic carbon. Relatively high Mo concentrations were found in those organic matter. Such Mo behavior implies direct microbial mediation of bio-essential elements from submarine hydrothermal fluids. Microscopic occurrence of organic carbon is often closely associated with sulfide minerals forming onion- or stromatolite-like structures. Such structures imply biologically induced sulfide mineralization in submarine hydrothermal environments. Stable isotope analyses indicate high activities of methanogens and methanotrophs with sulfate reducers only around the hydrothermal discharging zone. Those results indicate that ancient submarine hydrothermal fields were important for early ecosystem not only for metabolic energy usage but also uptake of bio-essential elements. However, the total energy flux from interior of the early Earth is known to be small. Such small energy flux constraints the extents of submarine hydrothermal activities on the early ocean floor and further suggests that biomass around the ancient submarine hydrothermal environments was also small. Therefore it is still an open question as to if ancient submarine hydrothermal environments were major geological fields for evolution of early life.
A smooth negative shift of organic carbon isotope ratios at an end-Permian mass extinction horizon in central pelagic Panthalassa Peer-reviewed

Satoshi Takahashi, Kunio Kaiho, Masahiro Oba, Takeshi Kakegawa

Palaeogeography, Palaeoclimatology, Palaeoecology　292　(3-4)　532-539　2010

DOI： 10.1016/j.palaeo.2010.04.025 　

ISSN： 0031-0182

eISSN： 1872-616X
Abundance of Zetaproteobacteria within crustal fluids in back-arc hydrothermal fields of the Southern Mariana Trough Peer-reviewed

Shingo Kato, Katsunori Yanagawa, Michinari Sunamura, Yoshinori Takano, Jun Ichiro Ishibashi, Takeshi Kakegawa, Motoo Utsumi, Toshiro Yamanaka, Tomohiro Toki, Takuroh Noguchi, Kensei Kobayashi, Arimichi Moroi, Hiroyuki Kimura, Yutaka Kawarabayasi, Katsumi Marumo, Tetsuro Urabe, Akihiko Yamagishi

Environmental Microbiology　11　(12)　3210-3222　2009/12

DOI： 10.1111/j.1462-2920.2009.02031.x 　

ISSN： 1462-2912

eISSN： 1462-2920
Spatial distribution, diversity and composition of bacterial communities in sub-seafloor fluids at a deep-sea hydrothermal field of the Suiyo Seamount Peer-reviewed

Shingo Kato, Kurt Hara, Hiroko Kasai, Takashi Teramura, Michinari Sunamura, Jun-ichiro Ishibashi, Takeshi Kakegawa, Toshiro Yamanaka, Hiroyuki Kimura, Katsumi Marumo, Tetsuro Urabe, Akihiko Yamagishi

DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS　56　(10)　1844-1855　2009/10

DOI： 10.1016/j.dsr.2009.05.004 　

ISSN： 0967-0637

eISSN： 1879-0119
Organic synthesis under impact conditions Invited Peer-reviewed

古川善博, 関根利守, 大庭雅寛, 掛川武, 中沢弘基

に本惑星科学誌　18　(4)　223-237　2009/10/01
Spatial distribution, diversity and composition of bacterial communities in sub-seafloor fluids at a deep-sea hydrothermal field of the Suiyo Seamount Peer-reviewed

Shingo Kato, Kurt Hara, Hiroko Kasai, Takashi Teramura, Michinari Sunamura, Jun ichiro Ishibashi, Takeshi Kakegawa, Toshiro Yamanaka, Hiroyuki Kimura, Katsumi Marumo, Tetsuro Urabe, Akihiko Yamagishi

Deep-Sea Research Part I: Oceanographic Research Papers　56　(10)　1844-1855　2009/10

DOI： 10.1016/j.dsr.2009.05.004 　

ISSN： 0967-0637
A new age model for the sediment cores from Academician ridge (Lake Baikal) based on high-time-resolution AMS ¹⁴C data sets over the last 30 kyr: Paleoclimatic and environmental implications Peer-reviewed

Takahiro Watanabe, Toshio Nakamura, Fumiko Watanabe Nara, Takeshi Kakegawa, Mitsugu Nishimura, Makoto Shimokawara, Tetsuya Matsunaka, Ryoko Senda, Takayoshi Kawai

Earth and Planetary Science Letters　286　(3-4)　347-354　2009/09/15

DOI： 10.1016/j.epsl.2009.06.046 　

ISSN： 0012-821X
A new age model for the sediment cores from Academician ridge (Lake Baikal) based on high-time-resolution AMS C-14 data sets over the last 30 kyr: Paleoclimatic and environmental implications Peer-reviewed

Takahiro Watanabe, Toshio Nakamura, Fumiko Watanabe Nara, Takeshi Kakegawa, Mitsugu Nishimura, Makoto Shimokawara, Tetsuya Matsunaka, Ryoko Senda, Takayoshi Kawai

EARTH AND PLANETARY SCIENCE LETTERS　286　(3-4)　347-354　2009/09

DOI： 10.1016/j.epsl.2009.06.046 　

ISSN： 0012-821X

eISSN： 1385-013X
High-time resolution AMS ¹⁴C data sets for Lake Baikal and Lake Hovsgol sediment cores: Changes in radiocarbon age and sedimentation rates during the transition from the last glacial to the Holocene Peer-reviewed

Takahiro Watanabe, Toshio Nakamura, Fumiko Watanabe Nara, Takeshi Kakegawa, Kazuho Horiuchi, Ryoko Senda, Takefumi Oda, Mitsugu Nishimura, Genki Inoue Matsumoto, Takayoshi Kawai

Quaternary International　205　(1-2)　12-20　2009/08/15

DOI： 10.1016/j.quaint.2009.02.002 　

ISSN： 1040-6182
High-time resolution AMS C-14 data sets for Lake Baikal and Lake Hovsgol sediment cores: Changes in radiocarbon age and sedimentation rates during the transition from the last glacial to the Holocene Peer-reviewed

Takahiro Watanabe, Toshio Nakamura, Fumiko Watanabe Nara, Takeshi Kakegawa, Kazuho Horiuchi, Ryoko Senda, Takefumi Oda, Mitsugu Nishimura, Genki Inoue Matsumoto, Takayoshi Kawai

QUATERNARY INTERNATIONAL　205　12-20　2009/08

DOI： 10.1016/j.quaint.2009.02.002 　

ISSN： 1040-6182

eISSN： 1873-4553
Microbial communities in iron-silica-rich microbial mats at deep-sea hydrothermal fields of the Southern Mariana Trough Peer-reviewed

Shingo Kato, Chiyori Kobayashi, Takeshi Kakegawa, Akihiko Yamagishi

Environmental Microbiology　11　(8)　2094-2111　2009/08

DOI： 10.1111/j.1462-2920.2009.01930.x 　

ISSN： 1462-2912

eISSN： 1462-2920
Contrast ecosystem between aerobic and anaerobic bacteria recorded in 3.0 Ga sedimentary rocks of the Atikokan-Lumby Lake area, Canada

T. Kakegawa, M. Saito

GEOCHIMICA ET COSMOCHIMICA ACTA　73　(13)　A614-A614　2009/06

ISSN： 0016-7037
Microbial Communities in Sulfide Structures of Active and Inactive Vents at Deep-sea Hydrothermal Fields at the Southern Mariana Trough. Peer-reviewed

Kato,S, Takano,Y, Kakegawa,T, Oba,H, Inoue,K, Kobayashi,C, Utsumi,M, Marumo,K, Kobayashi,K, Ito,Y, Ishibashi,J.-I, Yamagishi,A

Environmental Microbiology　doi:10.1111/j.1462-2920.　2009/02
Stable isotope characterization of fluids from the Lake Chany complex, western Siberia, Russian Federation Peer-reviewed

C. Mizota, H. Doi, E. Kikuchi, S. Shikano, T. Kakegawa, N. Yurlova, A. K. Yurlov

Applied Geochemistry　24　(2)　319-327　2009/02

DOI： 10.1016/j.apgeochem.2008.10.009 　

ISSN： 0883-2927
Influence of Late Heavy Bombardment to the atmosphere and ocean composition at late Hadean

Furukawa Yoshihiro, Sekine Toshimori, Oba Masahiro, Kakegawa Takeshi, Hiromoto Nakazawa

Abstracts of Annual Meeting of the Geochemical Society of Japan　56　273-273　2009
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.56.0.273.0 　
Sulfide sulfur isotope profiles in the pelagic Panthalassic deep-sea during the end-Permian.

Takahashi Satoshi, Kaiho Kunio, Watanabe Takahiro, Kakegawa Takeshi, Oba Masahiro

Abstracts of Annual Meeting of the Geochemical Society of Japan　56　305-305　2009
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.56.0.305.0 　
Biomolecule formation by oceanic impacts on early Earth Peer-reviewed

Yoshihiro Furukawa, Toshimori Sekine, Masahiro Oba, Takeshi Kakegawa, Hiromoto Nakazawa

Nature Geoscience　2　(1)　62-66　2009/01

DOI： 10.1038/ngeo383 　

ISSN： 1752-0894

eISSN： 1752-0908
Source of food for fish around river mouth Invited Peer-reviewed

伊藤絹子, 掛川武

安定同位体スコープで覗く海洋生物の生体　159　70-84　2008/10/01
Geochemistry of sulfide chimneys and basement pillow lavas at the southern mariana trough (12.55°N-12.58°N) Peer-reviewed

Takeshi Kakegawa, Motoo Utsumi, Katsumi Marumo

Resource Geology　58　(3)　249-266　2008/09/01
Publisher: Blackwell Publishing Ltd
DOI： 10.1111/j.1751-3928.2008.00060.x 　

ISSN： 1344-1698
Impact synthesis of organic compounds: Implication for their mass production on the early Earth Peer-reviewed

Y. Furukawa, T. Sekine, M. Oba, T. Kakegawa, H. Nakazawa

GEOCHIMICA ET COSMOCHIMICA ACTA　72　(12)　A286-A286　2008/07

ISSN： 0016-7037

eISSN： 1872-9533
Contrast compositions of minerals, kerogens and lipid-biomarkers in 1.9 Ga shallow- and deep-water sedimentary rocks of the Gunflint Formation, Canada Peer-reviewed

A. Ishida, T. Kakegawa, M. Oba

GEOCHIMICA ET COSMOCHIMICA ACTA　72　(12)　A412-A412　2008/07

ISSN： 0016-7037

eISSN： 1872-9533
Contrast occurrence of banded iron formations in western part of Isua Spracrustal Belt, West Greenland Peer-reviewed

Y. Ohtomo, T. Kakegawa

GEOCHIMICA ET COSMOCHIMICA ACTA　72　(12)　A702-A702　2008/07

ISSN： 0016-7037

eISSN： 1872-9533
Prebiotic polymerization of amino acids on the early Earth: Chemical evolution in the Hadean oceanic crusts Peer-reviewed

Takeshi Kakegawa, Shohei Ohara, Taketo Ishiguro, Hiroki Abiko, Hiromoto Nakazawa

GEOCHIMICA ET COSMOCHIMICA ACTA　72　(12)　A444-A444　2008/07

ISSN： 0016-7037

eISSN： 1872-9533
Timing and magnitude of early Aptian extreme warming: Unraveling primary δ¹⁸O variation in indurated pelagic carbonates at Deep Sea Drilling Project Site 463, central Pacific Ocean Invited Peer-reviewed

Atsushi Ando, Kunio Kaiho, Hodaka Kawahata, Takeshi Kakegawa

Palaeogeography, Palaeoclimatology, Palaeoecology　260　(3-4)　463-476　2008/04

DOI： 10.1016/j.palaeo.2007.12.007 　

ISSN： 0031-0182
Timing and magnitude of early Aptian extreme warming: Unraveling primary delta O-18 variation in indurated pelagic carbonates at Deep Sea Drilling Project Site 463, central Pacific Ocean Peer-reviewed

Atsushi Ando, Kunio Kaiho, Hodaka Kawahata, Takeshi Kakegawa

PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY　260　(3-4)　463-476　2008/04

DOI： 10.1016/j.palaeo.2007.12.007 　

ISSN： 0031-0182

eISSN： 1872-616X
Stable isotopic characterization of carbon, nitrogen and sulfur uptake of Acharax japonica from central Japan Peer-reviewed

Toshiro Yamanaka, Chitoshi Mizota, Kazuyo Matsuyama-Serisawa, Takeshi Kakegawa, Jun Ichi Miyazaki, Mami Mampuku, Hiroaki Tsutsumi, Yoshihiro Fujiwara

Plankton and Benthos Research　3　(1)　36-41　2008/02

DOI： 10.3800/pbr.3.36 　

ISSN： 1880-8247
Prebiotic peptide formations under high pressure and temperature conditions: Importance of dynamics of the early Earth

Kakegawa Takeshi

Abstracts of Annual Meeting of the Geochemical Society of Japan　55　10-10　2008
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.55.0.10.0 　

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How to polymerize single amino acids into peptides is the most fundamental question for origin of life. In addition, there exist no clear constraints as to which geological conditions are suitable for such peptide formations. We performed several high pressure and temperature experiments. We were successful to polymerize glycine, valine and aspalic acid. The results further suggest that Hadean oceanic crustal conditions were suitable for peptide formations.
Ether lipids of archaea as tools for environmental studies.

Oba Masahiro, Kaiho Kunio, Kakegawa Takeshi, Yamamoto Masanobu, Sakata Susumu, Furukawa Yoshihiro, Sato Seigo

Abstracts of Annual Meeting of the Geochemical Society of Japan　55　21-21　2008
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.55.0.21.0 　
Early biosphere recorded in 3.8 to 3.0 Ga marine sedimentary rocks: constraints from micro-analyses of stable isotopes

Kakegawa Takeshi

Abstracts of Annual Meeting of the Geochemical Society of Japan　55　385-385　2008
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.55.0.385.0 　
Framboidal pyrite in mudstones of the Hokuroku district, Akita prefecture and their indication for paleoenvironments

Fukasawa Midori, Kakegawa Takeshi

Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences　2008　168-168　2008
Publisher: Japan Association of Mineralogical Sciences
DOI： 10.14824/jakoka.2008.0.168.0 　

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Mineralogical and geochemical analysis were performed on mudstone sedimented on the Kuroko deposits, which were formed ca. 13Ma. Detailed size analyses of framboidal pyrite suggest that (1) bottom oceans became anoxic and euxinic right after the Kuroko formation; and (2) bottom oceans became oxic a few million years later. These are corresponded to sulfur isotope compositions of pyrite. In the euxinic ocean water, complicated microbial mediation of sulfur occurred resulting in very negative sulfur isotope compositions. In later stage, simple sulfate-reduction in sediments was responsible for pyrite formation.
The first life was generated by dynamics of the early Earth

Kakegawa Takeshi

Annual Meeting of the Geological Society of Japan　2008　32-32　2008
Publisher: The Geological Society of Japan
DOI： 10.14863/geosocabst.2008.0.32.0 　

ISSN： 1348-3935
Formation of organic molecules by the impact reaction among meteoritic minerals, water and nitrogen

Furukawa Yoshihiro, Sekine Toshimori, Oba Masahiro, Kakegawa Takeshi, Nakazawa Hiromoto

Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences　2008　22-22　2008
Publisher: Japan Association of Mineralogical Sciences
DOI： 10.14824/jakoka.2008.0.22.0 　

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Frequent impacts of extraterrestrial objects melted the embryonic Earth, forming an inorganic body with a CO2 and N2-rich atmosphere. How and when abundant organic molecules appeared in such an inorganic world are fundamental inquiries into the origin of life. Here we report a facile impact synthesis of some biomolecules and their precursors from solid carbon (13C), iron, nickel, water, and nitrogen all of which would have been available during impact events on Earth's early oceans. Biomolecules and their precursors identified in the present shock recovery experiments are carboxylic acids, amines, and an amino acid. Therefore impacts of extraterrestrial objects on Hadean oceans might have prepared organic molecules in necessary abundance, variety, and complexity for life's origin.
The most important water-rock interaction on the early Earth: Meteorite-ocean impact

Kakegawa Takeshi, Sekine Toshimori, Furukawa Yoshihiro, Nakazawa Hiromoto

Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences　2008　23-23　2008
Publisher: Japan Association of Mineralogical Sciences
DOI： 10.14824/jakoka.2008.0.23.0 　

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Shock-recovery experiments were performed in order to water-rock interaction during the meteorite ocean impact events. Rapid formation of serpentine and generation of ammonia from atmospheric nitrogen were found in the present study. Those results imply that the late heavy bombardment was controlling elemental cycles on the Earth during the late Hadean age.
Radiocarbon chronology of a sediment core from Lake Pumoyum Co in the southeastern Tibetan plateau Peer-reviewed

T. Watanabe, T. Nakamura, M. Nishimura, T. Matsunaka, M. Minami, T. Kakegawa, F. W. Nara, L. Zhu

INTERNATIONAL ASSOCIATION OF THEORETICAL AND APPLIED LIMNOLOGY, VOL 30, PT 4, PROCEEDINGS　30　611-614　2008

ISSN： 0368-0770
Geochemistry of sulfide chimneys and basement pillow lavas at the Southern Mariana Trough (12.55 degrees N-12.58 degrees N) Peer-reviewed

Takeshi Kakegawa, Motoo Utsumi, Katsumi Marumo

RESOURCE GEOLOGY　58　(3)　249-266　2008

DOI： 10.1111/j.1751-3928.2008.00060.x 　

ISSN： 1344-1698
Paleoredox, biotic and sulfur-isotopic changes associated with the end-Permian mass extinction in the western Tethys Peer-reviewed

P. Gorjan, K. Kaiho, T. Kakegawa, S. Niitsuma, Z. Q. Chen, Y. Kajiwara, A. Nicora

Chemical Geology　244　(3-4)　483-492　2007/10/15

DOI： 10.1016/j.chemgeo.2007.07.003 　

ISSN： 0009-2541
Paleoredox, biotic and sulfur-isotopic changes associated with the end-Permian mass extinction in the western Tethys Invited Peer-reviewed

P. Gorjan, K. Kaiho, T. Kakegawa, S. Niitsuma, Z. Q. Chen, Y. Kajiwara, A. Nicora

CHEMICAL GEOLOGY　244　(3-4)　483-492　2007/10

DOI： 10.1016/j.chemgeo.2007.07.003 　

ISSN： 0009-2541

eISSN： 1872-6836
Impact-generated ultrafine particles of olivine and serpentine suggesting a source of aerogels in the air of the early Earth Peer-reviewed

Y. Furukawa, T. Kakegawa, T. Sekine, H. Nakazawa

GEOCHIMICA ET COSMOCHIMICA ACTA　71　(15)　A300-A300　2007/08

ISSN： 0016-7037
Aerobic and anaerobic microbial ecosystem recorded in the Steep Rock Group, Ontario, Canada Peer-reviewed

T. Kakegawa, M. Haikawa

GEOCHIMICA ET COSMOCHIMICA ACTA　71　(15)　A458-A458　2007/08

ISSN： 0016-7037
Geochemistry and TEM observation of graphite in 3.8 Ga metasedimentary rocks in Isua Supracrustal Belt Peer-reviewed

Y. Ohtomo, T. Kakegawa

GEOCHIMICA ET COSMOCHIMICA ACTA　71　(15)　A735-A735　2007/08

ISSN： 0016-7037

eISSN： 1872-9533
Catalytic potential of silicate, oxide and sulfide minerals for the abiotic polymerization of glycine under high pressure and temperature conditions Peer-reviewed

Shohei Ohara, Takeshi Kakegawa, Hiromoto Nakazawa

GEOCHIMICA ET COSMOCHIMICA ACTA　71　(15)　A731-A731　2007/08

ISSN： 0016-7037
Carbon isotope records of terrestrial organic matter and occurrence of planktonic foraminifera from the Albian stage of Hokkaido, Japan: Ocean-atmosphere δ¹³C trends and chronostratigraphic implications Peer-reviewed

Atsushi Ando, Takeshi Kakegawa

Palaios　22　(4)　417-432　2007/07

DOI： 10.2110/palo.2005.p05-104r 　

ISSN： 0883-1351

eISSN： 1938-5323
Carbon isotope records of terrestrial organic matter and occurrence of planktonic foraminifera from the Albian stage of Hokkaido, Japan: Ocean-atmosphere delta C-13 trends and chronostratigraphic implications Peer-reviewed

Atsushi Ando, Takeshi Kakegawa

PALAIOS　22　(4)　417-432　2007/07

DOI： 10.2110/palo.2005.p05-104r 　

ISSN： 0883-1351

eISSN： 1938-5323
Formation of ultrafine particles from impact-generated supercritical water Peer-reviewed

Yoshihiro Furukawa, Hiromoto Nakazawa, Toshimori Sekine, Takeshi Kakegawa

Earth and Planetary Science Letters　258　(3-4)　543-549　2007/06/30

DOI： 10.1016/j.epsl.2007.04.014 　

ISSN： 0012-821X
Pressure effects on the abiotic polymerization of glycine Peer-reviewed

Shohei Ohara, Takeshi Kakegawa, Hiromoto Nakazawa

ORIGINS OF LIFE AND EVOLUTION OF BIOSPHERES　37　(3)　215-223　2007/06

DOI： 10.1007/s11084-007-9067-4 　

ISSN： 0169-6149
Pressure effects on the abiotic polymerization of glycine Peer-reviewed

Shohei Ohara, Takeshi Kakegawa, Hiromoto Nakazawa

Origins of Life and Evolution of the Biosphere　37　(3)　215-223　2007/06

DOI： 10.1007/s11084-007-9067-4 　

ISSN： 0169-6149
Early Earth Environments and Remnants of Microbial Life Invited Peer-reviewed

Takeshi Kakegawa

Genetics　(20)　180-183　2006/12
Sr / Ca ratios as indicators of varying modes of pelagic carbonate diagenesis in the ooze, chalk and limestone realms Peer-reviewed

Atsushi Ando, Hodaka Kawahata, Takeshi Kakegawa

Sedimentary Geology　191　(1-2)　37-53　2006/09/15

DOI： 10.1016/j.sedgeo.2006.01.003 　

ISSN： 0037-0738

eISSN： 1879-0968
Sr/Ca ratios as indicators of varying modes of pelagic carbonate diagenesis in the ooze, chalk and limestone realms Peer-reviewed

Atsushi Ando, Hodaka Kawahata, Takeshi Kakegawa

SEDIMENTARY GEOLOGY　191　(1-2)　37-53　2006/09

DOI： 10.1016/j.sedgeo.2006.01.003 　

ISSN： 0037-0738

eISSN： 1879-0968
Sulfur and carbon isotope analyses of 2.7 Ga stromatolites, cherts and sandstones in the Jeerinah Formation, Western Australia Peer-reviewed

Takeshi Kakegawa, Hideyuki Nanri

Precambrian Research　148　(1-2)　115-124　2006/07/20

DOI： 10.1016/j.precamres.2006.03.005 　

ISSN： 0301-9268
Sulfur and carbon isotope analyses of 2.7 Ga stromatolites, cherts and sandstones in the Jeerinah Formation, Western Australia Peer-reviewed

Takeshi Kakegawa, Hideyuki Nanri

PRECAMBRIAN RESEARCH　148　(1-2)　115-124　2006/07

DOI： 10.1016/j.precamres.2006.03.005 　

ISSN： 0301-9268
Links of organic carbon cycling and burial to depositional depth gradients and establishment of a snowball Earth at 2.3Ga. Evidence from the Timeball Hill Formation, Transvaal Supergroup, South Africa Invited Peer-reviewed

L. L. Coetzee, Nicolas J. Beukes, Jens Gutzmer, T. Kakegawa

South African Journal of Geology　109　(1-2)　109-122　2006/06

DOI： 10.2113/gssajg.109.1-2.109 　

ISSN： 1012-0750

eISSN： 1996-8590
Chemical and biological evolution of early Earth: Constraints from banded iron formations Invited Peer-reviewed

Hiroshi Ohmoto, Yumiko Watanabe, Kosei E. Yamaguchi, Hiroshi Naraoka, Makoto Haruna, Takeshi Kakegawa, Ken Ichiro Hayashi, Yasuhiro Kato

Memoir of the Geological Society of America　198　291-333　2006

DOI： 10.1130/2006.1198(17) 　

ISSN： 0072-1069
34億年前の海洋環境で活動した光合成細菌の痕跡・酸素発生型か非酸素発生型か？

掛川武

蛋白質核酸酵素　50　64-65　2005/12
水曜海山海底熱水域の地下地質構造と硫化物硫黄同位体組成との関係 Peer-reviewed

掛川武, 野田雅一, 丸茂克美

海の科学　14　(2)　221-235　2005/12
Publisher: The Oceanographic Society of Japan
DOI： 10.5928/kaiyou.14.221 　

ISSN： 0916-8362

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The active submarine hydrothermal field of Suiyo Seamount was directly drilled in order to understand the geological structure and hydrothermal processes at the subsurface region. A contrasting geological structure was found between the central and eastern areas. A thick accumulation of volcanoclastic sediments on the seafloor is a notable feature of the central area. These sediments were extensively altered by hydrothermal fluids and heavily cemented by anhydrite. Networks of hydrothermal veins and vesicles are developed in this cemented zone. This cementing process isolates the reducing subsurface environment from the oxic seawater environment. In contrast, less porous dacite lavas and breccia are main constituents of the eastern area. Hydrothermal fluids migrate along fractures developed in dacite lavas and breccia at the eastern hydrothermal area. Analyses of sulfur isotope compositions were performed on sulfide minerals separated from drilled core samples. Sulfur isotope compositions of the eastern samples (APSK01) are rather homogeneous, ranging from +1.0 to +1.3‰. These homogenized values suggest simple precipitation of sulfides using isotopically homogeneous H₂S. Sulfur isotope compositions of sulfides from the central area are heterogeneous, ranging from +0.9 to +5.3‰. This indicates that isotope exchange occurred directly or indirectly between seawater sulfate and hydrothermal sulfides. Such regional difference in sulfur isotope compositions is tightly related to the difference in subsurface geological structure between the eastern and central regions of the Suiyo Seamount.
地球・生命ーその起源と進化

大谷栄治, 掛川武

共立出版　2005/10
High yield shock synthesis of ammonia from iron, water and nitrogen available on the early Earth Peer-reviewed

H Nakazawa, T Sekine, T Kakegawa, S Nakazawa

EARTH AND PLANETARY SCIENCE LETTERS　235　(1-2)　356-360　2005/06

DOI： 10.1016/j.epsl.2005.03.024 　

ISSN： 0012-821X

eISSN： 1385-013X
Analysis of the archaeal sub-seafloor community at Suiyo Seamount on the Izu-Bonin Arc Peer-reviewed

K Hara, T Kakegawa, K Yamashiro, A Maruyama, JI Ishibashi, K Marumo, T Urabe, A Yamagishi

SPACE LIFE SCIENCES: CLOSED ECOLOGICAL SYSTEMS: EARTH AND SPACE APPLICATIONS　35　(9)　1634-1642　2005

DOI： 10.1016/j.asr.2005.04.111 　

ISSN： 0273-1177
Analysis of the archaeal sub-seafloor community at Suiyo Seamount on the Izu-Bonin Arc Peer-reviewed

Kurt Hara, Takeshi Kakegawa, Kan Yamashiro, Akihiko Maruyama, Jun Ichiro Ishibashi, Katsumi Marumo, Tetsuro Urabe, Akihiko Yamagishi

Advances in Space Research　35　(9 SPEC. ISS.)　1634-1642　2005

DOI： 10.1016/j.asr.2005.04.111 　

ISSN： 0273-1177
Oceanithermus desulfurans sp. nov., a novel thermophilic, sulfur-reducing bacterium isolated from a sulfide chimney in Suiyo Seamount Peer-reviewed

Koji Mori, Takeshi Kakegawa, Yowsuke Higashi, Ko Ichi Nakamura, Akihiko Maruyama, Satoshi Hanada

International Journal of Systematic and Evolutionary Microbiology　54　(5)　1561-1566　2004/09

DOI： 10.1099/ijs.0.02962-0 　

ISSN： 1466-5026
Oceanithermus desulfurans sp nov., a novel thermophilic, sulfur-reducing bacterium isolated from a sulfide chimney in Suiyo Seamount Peer-reviewed

K Mori, T Kakegawa, Y Higashi, K Nakamura, A Maruyama, S Hanada

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY　54　1561-1566　2004/09

DOI： 10.1099/ijs.0.02962-0 　

ISSN： 1466-5026

eISSN： 1466-5034
Heavy metal enrichment in Archean carbon-rich samples: Hint to early carbon-metal compounds for enzyme formation? Peer-reviewed

T Kakegawa, Y Ohtomo, H Nakazawa, M Rosing

GEOCHIMICA ET COSMOCHIMICA ACTA　68　(11)　A799-A799　2004/06

ISSN： 0016-7037

eISSN： 1872-9533
グリーンランド・イスア地域の岩石に刻まれた初期地球の姿 Invited

掛川武

地質ニュース　596　60-65　2004/05
GEOCHEMISTRY OF NITROGEN IN VOLCANIC ROCKS ALTERED BY SUBMARINE HYDROTHERMAL ACTIVITIES AT THE SUIYO SEAMOUNT, IZU-OGASAWARA ARC, JAPAN Peer-reviewed

Noda M, Kakegawa T

Water Dynamics Proceeding　vol.1　153-156　2004/03
Importance of water/rock interaction at ancient sub-seafloor regions to supply bio-essential elements to early biota Peer-reviewed

Kakegawa T

Water Dynamics Proceeding　vol.1　115-116　2004/03
微生物学と地球科学のわかちがたい関係 Peer-reviewed

遠藤一佳, 南澤究, 掛川武, 犬伏和之

科学　74　(2)　166-169　2004/02
Publisher:
ISSN： 0022-7625
Geological study of carbonatization of the 3.8 Ga Isua spracrustal Belt and abiological graphite generation.

Ohtomo, Y, Kakegawa, T

Proceedings of the Second International Workshop, Water Dynamics　1　217-218　2004
Abnormal carbon isotope records of organic matter in 2.7 Ga to 2.1 Ga marine sediments and its implication to the early life evolution Invited Peer-reviewed

Takeshi Kakegawa

Japanese Magazine of Mineralogical and Petrological Sciences　33　(3)　141-145　2004

DOI： 10.2465/gkk.33.141 　

ISSN： 1345-630X

eISSN： 1349-7979
Establishment of the phosphorous cycle in early Archean oceans

T Kakegawa

GEOCHIMICA ET COSMOCHIMICA ACTA　67　(18)　A194-A194　2003/09

ISSN： 0016-7037
A novel lineage of sulfate-reducing microorganisms: Thermodesulfobiaceae fam. nov., Thermodesulfobium narugense, gen. nov., sp. nov., a new thermophilic isolate from a hot spring Peer-reviewed

Koji Mori, Hongik Kim, Takeshi Kakegawa, Satoshi Hanada

Extremophiles　7　(4)　283-290　2003/08

DOI： 10.1007/s00792-003-0320-0 　

ISSN： 1431-0651

eISSN： 1433-4909
Stratigraphic carbon isotope fluctuations of detrital woody materials during the Aptian Stage in Hokkaido, Japan: Comprehensive δ ¹³C data from four sections of the Ashibetsu area Peer-reviewed

Atsushi Ando, Takeshi Kakegawa, Reishi Takashima, Tsunemasa Saito

Journal of Asian Earth Sciences　21　(8)　835-847　2003/06

DOI： 10.1016/S1367-9120(02)00112-8 　

ISSN： 1367-9120
Activity of Sulfate-reducing Bacteria in Archean Oceans and their Living Environments

KAKEGAWA Takeshi

J. Geogr.　112　(2)　218-225　2003/04/25
Publisher: Tokyo Geographical Society
DOI： 10.5026/jgeography.112.2_218 　

ISSN： 0022-135X

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Sulfate-reducing bacteria (SRB) are considered to be one of the oldest micro-organisms in the Earth history. Sulfur isotope data of sedimentary pyrite indicate that SRB have been active at least since 3.5 Ga. However, living environments of SRB, such as concentration level of sulfate in the Archean oceans and sulfur flux into Archean oceans, have been debated vigorously. Detailed sulfur isotope studies were performed on individual pyrite crystals in black shale and chert samples collected from several Archean greenstone belts. Sulfur isotope compositions of pyrite in all samples are fractionated, suggesting their biogenic origin. It is found that some representative sample sets from 2.7 Ga greenstone belts show a good correlation between organic carbon and pyrite sulfur concentrations. These results suggest that Archean oceans have been sulfate-rich at least since 2.7 Ga. This sulfate-rich ocean model conflicts with the sulfate-poor ocean model based on the mass independent fractionation of sulfur isotopes.
初期地球環境下での微生物進化 Peer-reviewed

Takeshi Kakegawa

日本惑星科学会、遊星人　(3)　14-18　2003/03
最古の岩石が秘める生命起源へのヒント Peer-reviewed

KAKEGAWA Takeshi

化学　58　(7)　30-31　2003
Geochemical cycles of bio-essential elements on the early earth and their relationships to origin of life Peer-reviewed

Takeshi Kakegawa, Masakazu Noda, Hideyuki Nannri

Resource Geology　52　(2)　83-89　2002/06/01

DOI： 10.1111/j.1751-3928.2002.tb00121.x 　

ISSN： 1344-1698
Activities of early life in the Archean oceans: influence from submarine hydrothermal activities Peer-reviewed

Takeshi kakegawa

origin of life and geochemistry　50-63　2002/03
New perspective on Aptian carbon isotope stratigraphy: Data from δ¹³C records of terrestrial organic matter Peer-reviewed

Atsushi Ando, Takeshi Kakegawa, Reishi Takashima, Tsunemasa Saito

Geology　30　(3)　227-230　2002/03

DOI： 10.1130/0091-7613(2002)030<0227:NPOACI>2.0.CO;2 　

ISSN： 0091-7613
Influence of submarine hydrothermal activities onto the Archean ocean chemistry and ecosystem.

T Kakegawa

ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY　221　U544-U544　2001/04

ISSN： 0065-7727
Biological activities and evolution of life during early stage of the Earth history: constraints from the stable isotope records Peer-reviewed

Takeshi Kakegawa

Viva Origino　(28)　191-208　2001
Biological activities and evolution of life during early stage of the Earth history : Constraints from the stable isotope records Peer-reviewed

KAKEGAWA Takeshi

Viva Origino　28　(4)　191　2000
Sulfur and carbon isotope analyses of the 2.7 Ga Jeerinah Formation, Fortescue Group, Australia Peer-reviewed

Takeshi Kakegawa, Yukio Kasahara, Ken Ichiro Hayashi, Hiroshi Ohmoto

Geochemical Journal　34　(2)　121-133　2000

DOI： 10.2343/geochemj.34.121 　

ISSN： 0016-7002

eISSN： 1880-5973
Sulfur isotope evidence for the origin of 3.4 to 3.1 Ga pyrite at the Princeton gold mine, Barberton Greenstone Belt, South Africa Peer-reviewed

Takeshi Kakegawa, Hiroshi Ohmoto

Precambrian Research　96　(3-4)　209-224　1999/07

DOI： 10.1016/s0301-9268(99)00006-6 　

ISSN： 0301-9268

eISSN： 1872-7433
Sulfur isotope evidence for the origin of 3.4 to 3.1 Ga pyrite at the Princeton gold mine, Barberton Greenstone Belt, South Africa Peer-reviewed

T Kakegawa, H Ohmoto

PRECAMBRIAN RESEARCH　96　(3-4)　209-224　1999/07

DOI： 10.1016/S0301-9268(99)00006-6 　

ISSN： 0301-9268

eISSN： 1872-7433
Geochemistry of the 2.O Ga Rove Formation, Canada, suggests an early establishment of the modern style elemental cycles mediated by biological activities Peer-reviewed

KAKEGAWA Takeshi

Geological Society of America, annual meeting, Abstract with program　(118)　1999
Origins of pyrites in the ~2.5 Ga Mt. McRae Shale, the Hamersley District, Western Australia Peer-reviewed

Takeshi Kakegawa, Hajime Kawai, Hiroshi Ohmoto

Geochimica et Cosmochimica Acta　62　(19-20)　3205-3220　1998/10

DOI： 10.1016/S0016-7037(98)00229-4 　

ISSN： 0016-7037
High activity of sulphate-reducing bacteria in Archean and Proterozoic oceans and an early development of the Phanerozoic-style sulphur cycles Peer-reviewed

KAKEGAWA Takeshi

Mineralofical Magazine　(62A)　738-739　1998
Sulfur isotope geochemistry of sedimentary rocks from the Chapel Island Formation, Newfoundland, Canada Peer-reviewed

KAKEGAWA Takeshi

Geological Society of America, Annual Meeting　29　(6)　116　1997
3.4-billion-year-old biogenic pyrites from Barberton, South Africa: Sulfur isotope evidence Peer-reviewed

Hiroshi Ohmoto, Takeshi Kakegawa, Donald R. Lowe

Science　262　(5133)　555-557　1993

DOI： 10.1126/science.11539502 　

ISSN： 0036-8075

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Misc. 76

New morphotypes, cell-wall structures, and elemental distribution of the Gunflint microfossils

SASAKI Kouhei, ISHIDA Akizumi, TAKAHATA Naoto, SANO Yuji, KAKEGAWA Takeshi

日本地球惑星科学連合大会予稿集(Web)　2020　2020
Heterogeneity in nitrogen source for microbial activity recorded in 2.0 Ga Zaonega Formation, NW Russia

石田章純, 笹木晃平, 橋爪光, 掛川武, LEPLAND Aivo

日本地球惑星科学連合大会予稿集(Web)　2020　2020
Constraints on primary producers at 3.2 Ga Barberton oceans: geological and geochemical studies on chert samples from the Sheba Hills area, Barberton

齊藤光, 石田章純, 掛川武

日本地球惑星科学連合大会予稿集(Web)　2020　2020
古原生代ガンフリント層における含微化石堆積岩の鉱物学的および地球化学的研究

笹木晃平, 石田章純, 掛川武

日本地球惑星科学連合大会予稿集(Web)　2019　2019
Astrobiology: From the origins of life to the search for extraterrestrial intelligence

Akihiko Yamagishi, Takeshi Kakegawa, Tomohiro Usui

Astrobiology: From the Origins of Life to the Search for Extraterrestrial Intelligence　1-465　2019/01/01

DOI： 10.1007/978-981-13-3639-3 　
Preface

Akihiko Yamagishi, Takeshi Kakegawa, Tomohiro Usui

Astrobiology: From the Origins of Life to the Search for Extraterrestrial Intelligence　v-vi　2019/01/01

DOI： 10.1007/978-981-13-3639-3 　
二次イオン質量分析計を用いた有機物炭素窒素同位体比同時分析法の開発と地質試料への応用について

石田章純, 石田章純, KITAJIMA Kouki, WILLIFORD Kenneth H, TUITE Michael L, 掛川武, VALLEY John W

日本地球惑星科学連合大会予稿集(Web)　2018　2018
Geological and geochemical studies on Miocene diatomaceous sedimentary rocks at Akita and Aomori in Japan; role of sulfur in maturation of organic matter and petroleum formation

蛭田衣音, 掛川武, 石田章純

日本地球惑星科学連合大会予稿集(Web)　2018　2018
カナダ,ガンフリント層に産する約19億年前の微生物化石及び共存鉱物における地球化学的研究

笹木晃平, 石田章純, 掛川武

日本地球惑星科学連合大会予稿集(Web)　2018　2018
カナダ・アビティビ緑色岩帯Potterdoal鉱床における硫化物と有機物の地球化学的研究

大里武, 掛川武, 石田章純

日本地球惑星科学連合大会予稿集(Web)　2018　2018
The Rb/Sr ratio in Lake Baikal sediment for the last 33 kyr

WATANABE NARA Fumiko, WATANABE Takahiro, MIYAHARA Hiroko, KATO Takenori, KAKEGAWA Takeshi, YAMASAKI Shin-ichi, TSUCHIYA Noriyosi

名古屋大学加速器質量分析計業績報告書　27　126-128　2016/03
Publisher: 名古屋大学宇宙地球環境研究所年代測定研究部

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The long-term and high time resolution analysis of inorganic elements from Lake Baikal sediment revealed that source provenance of Rb has been changed during last glacial and post glacial period. Simultaneous fluctuations between the Rb/Sr ratio and the mean grain size indicate that the Rb/Sr ratio was influenced from the precipitation change (humidity) during the post glacial period. On the other hand, it can be supposed that the influence of loess sediment on the Rb/Sr ratio was found during the last glacial period. The 200-yr period variation of the Rb/Sr raito was found during the post glacial period. This 200-yr period is very close to those of TSI variation. This result indicates the strong influence of solar irradiance on the precipitation change in Lake Baikal region. 南シベリア南東部に位置するバイカル湖より長さ436cmの堆積物試料を採取し、堆積物中の無機金属元素測定を行った。試料は1cm間隔で切り分けられ、試料間隔ごとの時間解像度は約70年と見積もられる。堆積物中のRb及びSrは、完新世(約11,700年前から現在)にかけて、それぞれKとCaに対して高い相関を示した。一方、後期更新世(約33,000年前から11,700 年まで)においては、SrとCaは高い相関を示すが、RbとKに相関は見られなかった。乾燥化した時代において、Rbの濃集が起きていたと考えられる。Rb/Sr比の分布は、後期更新世において冬季モンスーン(East Asian winter monsoon)の指標である中国レス堆積物の粒度分布(Sun et al., 2011)とよく対応を示した。寒冷、乾燥期においてバイカル湖堆積物中のRb/Sr比が冬季モンスーンの指標となりうる可能性を示唆している。名古屋大学宇宙地球環境研究所年代測定研究部シンポジウム報告
Interactions among mineral, water and biomolecule by shock wave: morphological changes of olivine grains reacted with amino acid solutions by impact process

UMEDA Yuhei, FUKUNAGA Nao, SEKINE Toshimori, KOBAYASHI Takamichi, FURUKAWA Yoshihiro, KAKEGAWA Takeshi

日本地球惑星科学連合大会予稿集(Web)　2016　2016
Rapid change of sedimentation rate for Lake Baikal sediment core (VER99G12) corresponding with the melt water pulse (MWP)

Nara Watanabe Fumiko, Watanabe Takahiro, Kakegawa Takeshi, Nakamura Toshio, Kawai Takayoshi

名古屋大学加速器質量分析計業績報告書　26　51-54　2015/03
Publisher: 名古屋大学年代測定資料研究センター

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Lake Baikal sediment cores record the paleoclimatic and biological changes in the continental area corresponding with the global and local climate changes. The global climate records, such as the Younger Dryas event, the Dansgaard-Oeshger cycles and the Heinrich events during the late Quaternary period, have been also observed from the Lake Baikal sediment core. However, the climate response corresponding with the melt water puls-19Ka (MWP-19Ka) has not been observed yet from the Lake Baikal sediment core. Here we show the rapid changes of the sedimentation rate in Lake Baikal sediment core (VER99G12) at around 19 cal ka BP, which were recovered from the 14C analysis of total organic carbon. The sampling site of VER99G12 is located in front of the Selenga River, which provides the largest inflow into the lake. Therefore, the sediment core in this study was mainly composed of the deposition from the Selenga River watershed. Radiocarbon measurements were carried out using the Tandetron AMS system (Model-4130, HVEE) in Center for Chronological Research, Nagoya University. High-time resolution 14C data sets from the sediment core revealed the rapid increase in sedimentation rate corresponding with the global climate warming (MWP-19Ka). The change of grain size and the K/Ti atomic ratios in the core also responded at the period as well. These results suggest the increase in the precipitation in the continental area at around 19000 years ago. 最終氷期最盛期(Last Glacial Maximum: LGM、26.5-19.0 ka, Clark et al., 2009) において、海水準は現在よりも最大約130m低下していたことが報告されている(Yokoyama et al., 2011)。海洋堆積物やサンゴの年代測定結果より、LGM以降から現在の海水準へ上昇するまでの間、急激な海水準上昇イベントが3度(約19,000年前、約14,500年前、約11,500年前)発生したと推定されている(Deschamps et al., 2012; Peltierand Fairbanks 2006; Yokoyama et al., 2000). 一方でこれらの急激な海水準上昇期に、大陸内部における水循環変動がどのように変化したかについては、未だ良く分かっていない.ユーラシア大陸南東部、シベリア地域に位置するバイカル湖は、その地理的特性から地球上で最も鋭敏に日射量変動を受ける地域に位置しており、バイカル湖の湖底堆積物を用いて、特に第四紀の大陸域における環境変動および生物活動変遷が復元されてきた(e.g. Horiuchi et al., 2000, Watanebe et al., 2004, Nara et al., 2014). 本研究では、バイカル湖から採取された堆積物試料(VER99G12、堆積物試料長さ466cm) を用いて、堆積速度の変化からLGM 以降における降水量変動の推定を行い、急激な海水準上昇期に対応した大陸域での降水量増加を明らかにした.名古屋大学年代測定総合研究センターシンポジウム報告
カナダオンタリオ州,ガンフリント層中(19億年前)の海洋堆積岩における鉱物学的地球化学的研究

二階堂映美, 奈良郁子, 土屋範芳, 掛川武

日本地球惑星科学連合大会予稿集(Web)　2015　ROMBUNNO.BCG28‐P15 (WEB ONLY)　2015
O6-05 衝撃波によるギ酸およびアンモニアからのアミノ酸生成(口頭発表セッション6 表層進化・物質I,口頭発表)

古川善博, 鈴木千月香, 小林敬道, 関根利守, 中沢弘基, 掛川武

日本惑星科学会秋期講演会予稿集　2014　"O6-05"　2014/09/10
Publisher: 日本惑星科学会
チベット高原プマユムツォ湖堆積物の無機化学組成による過去約12,500年間のモンスーン活動の復元

渡邊隆広, 奈良郁子, 松中哲也, 山崎慎一, 土屋範芳, 箕浦幸治, 中村俊夫, 掛川武, FAGEL Nathalie, ZHU Liping, WANG Junbo, 西村弥亜

日本第四紀学会講演要旨集　44　127　2014/09/05
大陸内部湖沼堆積物に記録された最終氷期最盛期における1000年周期降水量変動

奈良郁子, 渡邊隆広, 掛川武, 箕浦幸治, 堀内一穂, 宮原ひろ子, OBROCHTA Stephen, 山崎慎一, 土屋範芳, 中村俊夫, 志知幸治, 河合崇欣

日本第四紀学会講演要旨集　44　112　2014/09/05
安定硫黄同位体組成(δ³⁴S)を指標とした東北地方太平洋沖地震による津波堆積物の供給源推定

奈良郁子, 渡邊隆広, 掛川武, 山崎慎一, 井上千弘, 土屋範芳

日本第四紀学会講演要旨集　44　141　2014/09/05
隕石海洋衝突によるアラニンの化学進化に対する酸素分圧の効果

梅田悠平, 関根利守, 古川善博, 掛川武, 小林敬道

高圧討論会講演要旨集　55th　2014

ISSN： 0917-6373
Geochemical and clay mineralogical studies of a sediment core from Lake Pumoyum Co : Implications for past climate changes in south Tibetan Plateau

WATANABE Takahiro, NARA Fumiko W, FAGEL Nathalie, TSUCHIYA Noriyoshi, INOUE Chihiro, YAMASAKI Shin-ichi, MATSUNAKA Tetsuya, NAKAMURA Toshio, MINOURA Koji, ZHU Liping, WANG Junbo, KAKEGAWA Takeshi, NISHIMURA Mitsugu

日本鉱物科学会年会講演要旨集　2013　30-30　2013/09/05

ISSN： 1348-6543
南アフリカ・バーバトン地域に産出する浅海性縞状鉄鉱層中のクロムの濃集

OTAKE TSUBASA, SAKAMOTO YUKI, ITO SHOICHI, YURIMOTO HISAYOSHI, KAKEGAWA TAKESHI

資源地質学会年会講演会講演要旨集　63rd　34　2013/06/26
西グリーンランド・イスア表成岩帯におけるグラファイトの成因と生命の痕跡

大友陽子, 掛川武, 石田章純

日本地球化学会年会講演要旨集　60th　2013
安定窒素同位体比が示す最終氷期―間氷期におけるバイカル・フブスグル湖内の窒素制限の変化

奈良郁子, 渡邊隆広, 掛川武, 箕浦幸治, 今井章雄, 堀内一穂, FAGEL Nathalie, 中村俊夫, 河合崇欣

日本第四紀学会講演要旨集　42　24　2012/08/20
Radiocarbon chronology of a sediment core from Lake Pumoyum Co : Implications for past climate changes in south Tibetan Plateau

FAGEL Nathalie, ZHU Liping, WANG Junbo, WATANABE Takahiro, NARA Fumiko Watanabe, MATSUNAKA Tetsuya, NAKAMURA Toshio, MINOURA Koji, KAKEGAWA Takeshi, NISHIMURA Mitsugu

名古屋大学加速器質量分析計業績報告書　23　149-155　2012/03
Publisher: 名古屋大学年代測定資料研究センター

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To reconstruct climatic and environmental changes in the south Tibetan Plateau, a 3.77-m-long sediment core (PY608E-PC) was obtained from Lake Pumoyum Co in August 2006. Because terrestrial plant residues are extremely rare in this core, radiocarbon dating was performed on the total organic carbon fraction. We also estimated the old carbon effect and radiocarbon reservoir age of the total organic carbon fraction. Using these estimates, a new radiocarbon chronology for past climatic changes from ca. 12,500 to 700 cal BP was established. The linear sedimentation rate of the core was founded to be constant at 32.0 cm/kyr, indicating stable sedimentation conditions in Lake Pumoyum Co from the period of the Younger Dryas to the Holocene.名古屋大学年代測定総合研究センターシンポジウム報告
シベリア・チベット地域の湖沼から採取した湖底柱状堆積物の放射性炭素年代測定―4:PY608E‐PCコア試料(チベット・プマニユムツォ湖)

渡邊隆広, 中村俊夫, 西村弥亜, 松中哲也, 奈良郁子, 掛川武, WANG Junbo, ZHU Liping

名古屋大学加速器質量分析計業績報告書　22　191-198　2011/03
12 Stability of amino acids and their oligomerization under high temperature and high pressure conditions(General Contributions,The 36^<th> annual meeting of the SSOEL-JAPAN (Abstracts))

Otake T., Taniguchi T., Furukawa Y., Nakazawa H., Kakegawa T.

Viva origino　39　12-12　2011
Publisher: 文部省科学研究費総合研究(B)「原始地球上における生命の起源に関する研究」班
ISSN： 0910-4003
段階燃焼法によって明らかにされた初期原生代有機物窒素同位体比の二相性

石田章純, 橋爪光, 掛川武

日本地球化学会年会講演要旨集　58th　2011
Polymerization of amino acids and their stability during diagenesis of marine sediments on the early Earth

OTAKE Tsubasa, TANIGUCHI Takashi, FURUKAWA Yoshihiro, NAKAZAWA Hiromoto, KAKEGAWA Takeshi

51　74-74　2010/10/11

ISSN： 0917-6373
Formation of organic compounds from elemental carbon by impact reaction

FURUKAWA Yoshihiro, SEKINE Toshimori, KAKEGAWA Takeshi, OBA Masahiro, NAKAZAWA Hiromoto

51　251-251　2010/10/11

ISSN： 0917-6373
Textures of pyrite precipitated from low temperature solution

NAGASE Toshiro, YAMADA Ryoichi, KAKEGAWA Takeshi

2010　123-123　2010/09/23

ISSN： 1348-6543
Enhanced biological nitrogen and sulfur cycles in the stratified 1.9 Ga Gunflint ocean

A. Ishida, K. Hashizume, M. Oba, T. Kakegawa

GEOCHIMICA ET COSMOCHIMICA ACTA　74　(12)　A447-A447　2010/06

ISSN： 0016-7037
Stability of amino acids and peptides during diagenesis on the early Earth

T. Otake, T. Taniguchi, Y. Furukawa, H. Nakazawa, T. Kakegawa

GEOCHIMICA ET COSMOCHIMICA ACTA　74　(12)　A782-A782　2010/06

ISSN： 0016-7037

eISSN： 1872-9533
Radiocarboin dating of Holocene soils from an island in Lake Pumoyum Co (southeastern Tibetan Plateau)

LIN Xiao, ZHU Liping, WATANABE Takahiro, NAKAMURA Toshio, NISHIMURA Mitsugu, MATSUNAKA Tetsuya, SAKAI Takahiro, HORIUCHI Kazuho, NARA Watanabe Fumiko, KAKEGAWA Takeshi

名古屋大学加速器質量分析計業績報告書　21　80-86　2010/03
Publisher: 名古屋大学年代測定資料研究センター

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Soil samples from an 85-cm-long continuous section (PY608ES, OS09-B) were collected from an island in Lake Pumoyum Co (southeastern Tibetan Plateau, -5020 m asl). To estimate past environmental conditions of Lake Pumoyum Co during the Holocene, we analyzed ^<14>C ages, stable carbon isotope compositions, and total organic carbon/total nitrogen (TOC/TN) atomic ratios of the soil samples. The ^<14>C measurements were performed with the Tandetron accelerator mass spectrometry system at the Center for Chronological Research, Nagoya University. The ^<14>C concentration in the surface layer (101 percent modern carbon; 5-10 cm soil depth) was nearly modern. A ^<14>C chronology of sequence indicated that continuous soil development began on the island in Lake Pumoyum Co at ca. 5000-6000 cal BP (at 63 cm soil depth, the top of a gravel layer). These results may reflect a decrease in the lake level in the middle Holocene. The age of the obvious lithologic boundary (ca. 5000-6000 cal BP) corresponds to the end of Holocene climate optimum. アジア地域における過去のモンスーン活動を復元するため、2006年および2009年にチベット高原南東部に位置するプマユムツォ湖の大島(28℃34'52''N, 90℃28'55''E; altitude, ～5020m asl)において、土壌(陸成堆積層)形成に関する現地調査および土壌試料採取を行った。現在の大島湖岸付近に、礫層と土壌層の明瞭な境界が見られる露頭を発見し、名古屋大学年代測定総合研究センターにおいて、大島から採取した土壌試料の放射性炭素年代測定を行った。本研究により､プマユムツォ湖・大島の湖岸付近における礫層と土壌層の境界年代は約6000-5000calBPであることが推察された。礫層は､現在の大島湖岸付近が水面下であった時代に形成された可能性が高い。約6000-5000 calBPは完新世の気候最適期(ヒブシサーマル期)の終末年代に相当する。従って、約6000-5000cal BP以降におけるモンスーン活動の低下により、プマユムツォ湖の湖水面が低下し、現在の大島湖岸付近に土壌が形成された可能性が考えられる。第22回名古屋大学年代測定総合研究センターシンポジウム平成21(2009)年度報告
S2-1 Relationship between Archean submarine hydrothermal and micro bial activities : importance to origin or evolution of life?(Symposium,The 35^<th> annual meeting of the SSOEL-JAPAN (Abstracts))

Kakegawa Takeshi

Viva origino　38　28-28　2010
Publisher: 文部省科学研究費総合研究(B)「原始地球上における生命の起源に関する研究」班
ISSN： 0910-4003
Formation of organic compounds by oceanic impacts of meteors on the early Earth

Furukawa Y, Sekine T, Oba M, Kakegawa T, Nakazawa H

Planetary People　18　226-23　2009/12
Publisher: The Japan Society for Planetary Science
Fe input on the early Earth produced life

Takeshi Kakegawa

Science　10　1128-1132　2009/10/01
Publisher: Iwanami
A9 生物有機分子はなぜ粘土鉱物親和的か(口頭発表,一般講演)

中沢弘基, 古川善博, 関根利守, 大場雅寛, 掛川武, 大原祥平

粘土科学討論会講演要旨集　(53)　34-35　2009/09/10
Publisher: 日本粘土学会
Weak photic-zone euxinia at the end of the Permian in central pelagic Panthalassa as recorded in marine organic carbon isotopes

S. Takahashi, K. Kaiho, M. Oba, T. Kakegawa

GEOCHIMICA ET COSMOCHIMICA ACTA　73　(13)　A1306-A1306　2009/06

ISSN： 0016-7037
Synthesis of organic molecules by ocean impacts on the early Earth

Y. Furukawa, T. Sekine, M. Oba, T. Kakegawa, H. Nakazawa

GEOCHIMICA ET COSMOCHIMICA ACTA　73　(13)　A405-A405　2009/06

ISSN： 0016-7037
Geochemistry of 1.9 Ga gunflint formation in Canada: Unique oceanic environments and microbial activities

A. Ishida, M. Oba, T. Kakegawa

GEOCHIMICA ET COSMOCHIMICA ACTA　73　(13)　A572-A572　2009/06

ISSN： 0016-7037
Radiocarbon dating of sediment cores from Siberian and Tibetan lakes (3) : A preliminary report for ^<14>C ages of the PY608W-PC core from Lake Pumoyum Co (southeastern Tibetan plateau)

Zhu Liping, WATANABE Takahiro, NAKAMURA Toshio, NISHIMURA Mitsugu, MATSUNAKA Tetsuya, IZUTSU Yasuhiro, MINAMI Motoyasu, NARA Watanabe Fumiko, KAKEGAWA Takeshi

名古屋大学加速器質量分析計業績報告書　20　88-92　2009/03
Publisher: 名古屋大学年代測定資料研究センター

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Pumoyum Co is fresh water lake formed by fault action, and located in the southeastern Tibetan plateau (28°34'N, 90°24'E, altitude: ～5030 m asl, lake surface area: 281 km2, maximum water depth: ～65 m). Lake Pumoyum Co has at least 40 m sedimentary sequence, which is believed to cover the latest Quatemary. A first continuous sediment core (PY104PC, core length; 4 m) was taken from the eastern part of Pumoyum Co in the April 2001 for the reconstruction of climatic changes on the area. For Lake Pumoyum Co, preliminary results for ^<14>C ages of plant residues in a sediment core have been reported by Watanabe et al (2008). In the previous ^<14>C chronology, estimation of changes in the sources of plant residues and reservoir effects were insufficient. Therefore, major c1imate boundary layers, such as Bølling- Allerød warm phase, have not been determined. In 2006, a new continuous sediment core (PY608W-PC， core length: 3.9m) was obtained using a piston corer from Lake Pumoyum Co (28°33'14"N; 90°28'17''E, at a water depth of 50 m). In this study, fine plant residues in the PY608W-PC core were concentrated by wet-sieving (opening, 125μm) and were picked up in order to eliminate the effect of old carbon. ^<14>C dating of the plant residues from the PY608WPC shows that the sediment core contains a continuous record, over the past 19 cal ka BP. The layer with transition into Bølling-Allerød (BA) warm phase from the last glacial period (～15 cal ka BP) was consistent with the obvious lithologic boundary (sudden disappearance for the macrophyte remains in sediment layer)第21回名古屋大学年代測定総合研究センターシンポジウム平成20(2008)年度報告
水曜海山人工熱水噴出孔における古細菌ならびにバクテリア由来の脂質バイオマーカーの炭素同位体分析

大庭雅寛, 佐藤誠悟, 石田章純, 掛川武, 海保邦夫, 古川善博, 坂田将

日本地球化学会年会講演要旨集　56th　2009
The presence of Zetaproteobacteria and its significance in sub-seafloor microbial ecosystem

Kato Shingo, Yanagawa Katsunori, Sunamura Michinari, Takano Yoshinori, Ishibashi Jun-ichiro, Kakegawa Takeshi, Utsumi Motoo, Yamanaka Toshiro, Toki Tomohiro, Noguchi Takuroh, Kimura Hiroyuki, Marumo Katsumi, Urabe Tetsuro, Yamagishi Akihiko

Abstracts of Annual Meeting of the Geochemical Society of Japan　56　(0)　8-8　2009
Publisher: GEOCHEMICAL SOCIETY OF JAPAN
DOI： 10.14862/geochemproc.56.0.8.0 　

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海洋地殻内部の帯水層には，微生物圏が広がっていると考えられている。しかしながら，地殻内微生物生態系の全貌を把握するには至っていない。近年、南部マリアナトラフ熱水域において海底掘削が行われ、それらの掘削孔から熱水（<40C）を採取することに成功した．その熱水試料の16S rRNA遺伝子解析の結果，熱水試料中にZetaproteobacteriaに近縁な真正細菌が存在することがわかった．新たに設計したプローブを用いたFISH法によって，この分類群が，熱水試料中の全原核生物（約10^5 cells/ml）の最大32%を占めることが示された．Zetaproteobacteriaが鉄酸化菌を含む分類群であることを考えると，この分類群は海洋地殻内の鉄酸化に重要な役割を担っている可能性がある．
110 P002 隕石構成鉱物、水および窒素の衝突反応による有機分子の生成(最優秀発表賞選考,オーラルセッション2,最優秀発表賞選考エントリーポスター,ポスターセッション1)

古川善博, 関根利守, 大庭雅寛, 掛川武, 中沢弘基

日本惑星科学会秋期講演会予稿集　2008　10-10　2008/11/01
Publisher: 日本惑星科学会
S-32 The first life was generated by dynamics of the early Earth

Kakegawa Takeshi

115　17-17　2008/09/15
Publisher: The Geological Society of Japan
O-34 High organic carbon content and a decrease in radiolarians at the end of the Permian in a newly discovered continuous pelagic section : a coincidence?

TAKAHASHI Satoshi, YAMAKITA Satoshi, SUZUKI Noritoshi, KAIHO Kunio, OBA Masahiro, KAKEGAWA Takeshi, EHIRO Masayuki

日本地質学会学術大会講演要旨　115　48-48　2008/09/15
Publisher: The Geological Society of Japan
DOI： 10.14863/geosocabst.2008.0.92.0 　
A3 初期地球における粘土鉱物と生物有機分子の起源 : 実証実験(口頭発表,一般講演)

中沢弘基, 古川善博, 関根利守, 大庭雅寛, 掛川武

粘土科学討論会講演要旨集　(52)　36-37　2008/09/03
Publisher: 日本粘土学会
Radiocarbon dating of sediment cores from Siberian and Tibetan lakes (2) : chronology for the PY104 and PY409 sediment cores from Lake Pumoyum Co, southeastern Tibetan plateau(Proceedings of the 20^<th> Symposium on Chronological Studies at the Nagoya Uni

WATANABE Takahiro, NAKAMURA Toshio, NISHIMURA Mitsugu, MATSUNAKA Tetsuya, KAKEGAWA Takeshi, Zhu Liping

Summaries of Researches using AMS at Nagoya University　19　51-58　2008/03
Publisher: Nagoya University

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Paleo-climatic records from the Tibetan Plateau provide important clues for understanding the global climate system and the Asian monsoon variability. Paleo-climatic changes in the central, northern and western Tibet have been documented in previous studies of sediments from several lakes (Fontes et al. 1993, Morrill et al., 2006). However, details of the continuous environmental changes during the late Quaternary period, in the southern part on the plateau are still unknown. Lake Pumoyum Co is located in the southeastern Tibetan plateau. In 2001-2004, continuous sediment cores (PY104 and PY409) were taken from the Pumoyum Co for the reconstruction of climatic changes. In this study, we carried out ^<14>C dating and stable carbon isotope measurements of plant residues and TOC from the Pumoyum Co sediment, covering the period from the last glacial to the Holocene. The upper part of the PY104 (180-0 cm depth) was dated as Holocene, using the ^<14>C measurement of the plant residues (after ca. 10 cal ka BP). In this study, the ^<14>C dating of the plant residues revealed that the PY104 contained a record from the end of the last glacial period to the present, over the past 18.9 cal ka BP. The calibrated ages for the plant residues of the PY104 became progressively older, with their depths ranging from 51 to 369 cm. The calibrated ages of the plant residues in the sediments were found to be younger than those of the TOC by ca. 600-7800 yr. This result could have been caused by the relatively large supply of terrestrial organic materials containing old carbon ("old carbon effects" from lake terrace, paleosol and/or stratum with dead ^<14>C).
チベット高原南東部・プマユムツォ湖における過去２万年間の有機物循環と環境変動の解析

渡邊隆広, 中村俊夫, 西村弥亜, 松中哲也, 奈良郁子, 掛川武, ZHU Liping

日本陸水学会講演要旨集　73　(0)　264-264　2008
Publisher: 日本陸水学会
第四回日独先端科学シンポジウム：新しい伝統の予感

掛川武

学術月報　61　(1)　59-61　2008/01/01
Publisher: 日本学術振興会
ISSN： 0387-2440
Experimental evidence of serpentinization of olivine by impact : possible formation of water carrier in the early solar system

FURUKAWA Yoshihiro, KAKEGAWA Takeshi, SEKINE Toshimori, NAKAZAWA Hiromoto

2007　71-71　2007/09/22

ISSN： 1348-6543
湖底堆積物の安定同位体比および放射性炭素年代測定によるチベット南西部・プマユムツォ湖の古環境変動解析

渡邊隆広, 中村俊夫, 西村弥亜, 松中哲也, 掛川武, 奈良郁子, ZHU Liping

日本陸水学会講演要旨集　72　(0)　90-90　2007
Publisher: 日本陸水学会
DOI： 10.14903/jslim.72.0.90.0 　
A delta S-34(sulfate) increase at the Frasnian-Famennian (Late Devonian) transition

P. Gorjan, T. Kakegawa, J. -G. Casier, K. Kaiho

GEOCHIMICA ET COSMOCHIMICA ACTA　70　(18)　A210-A210　2006/08

DOI： 10.1016/j.gca.2006.06.422 　

ISSN： 0016-7037
Significance of meta-stable sulfide minerals in organic carbon-rich sedimentary rocks of the 2.77 Ga Mt. Roe Basalt in Western Australia

Niitsuma S, Kakegawa T, Nagase T, Nedachi M

Annual Meeting of the Geological Society of Japan　2005　(0)　59-59　2005
Publisher: The Geological Society of Japan
DOI： 10.14863/geosocabst.2005.0_59_1 　

ISSN： 1348-3935
B2. モンモリロナイト触媒による高圧下でのペプチド合成(第48回粘土科学討論会発表論文抄録)

大原祥平, 掛川武, 中沢弘基

粘土科学　44　(2)　91-92　2004/12/16
Publisher: 日本粘土学会
ISSN： 0470-6455
Rock Magnetism of the 2.77 Ga Mt Roe basalt, Pilbara, Australia

NEDACHI M, SAKAKI H, NIITSUMA S, KODAMA K, KAKEGAWA T

日本鉱物学会・学術講演会,日本岩石鉱物鉱床学会学術講演会講演要旨集　2004　250-250　2004/09/22

ISSN： 1348-6543
Hydrothermal system on the 2.77 Ga Mt Roe basalt, Pilbara Craton, Western Australia

NEDACHI M, SUGITA T, NEDACHI Y, KAKEGAWA T, NIITSUMA S, TERASHIMA K, NOZAKI J, OHMOTO H

日本鉱物学会・学術講演会,日本岩石鉱物鉱床学会学術講演会講演要旨集　2004　266-266　2004/09/22

ISSN： 1348-6543
Dynamism of the early Earth and chemical evolution

Nakazawa Hiromoto, Kakegawa Takeshi, Ohara Shohei, Furukawa Yoshihiro

Viva origino　32　(1)　12-12　2004
Publisher: 文部省科学研究費総合研究(B)「原始地球上における生命の起源に関する研究」班
ISSN： 0910-4003
Polymerization of amino acids under the temperature and pressure of diagenesis : The possibility of chemical evolution in sediments

Ohara Shohei, Furukawa Yoshihiro, Kakegawa Takeshi, Nakazawa Hiromoto

Viva origino　32　(1)　14-14　2004
Publisher: 文部省科学研究費総合研究(B)「原始地球上における生命の起源に関する研究」班
ISSN： 0910-4003
Formation of amino acids from graphite : Origin of biomolecules by meteorites impact to the early ocean

Furukawa Yoshihiro, Ohara Shohei, Kakegawa Takeshi, Nakazawa Hiromoto

Viva origino　32　(1)　13-13　2004
Publisher: 文部省科学研究費総合研究(B)「原始地球上における生命の起源に関する研究」班
ISSN： 0910-4003
Sulfide mineralization in the 3.46 Ga Towers formation at the Salgash area, Pilbara Craton, Western Australia

Kitazono Satoshi, Nedachi Munetomo, Niitsuma Sachiko, Kakegawa Takeshi

Abstracts for Annual Meeting of Japan Association of Mineralogical Sciences　2004　(0)　93-93　2004
Publisher: Japan Association of Mineralogical Sciences

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Pilbara Craton, Western Australia, consists of two different tectonic components; an older Archean granite-greenstone basement formed 3.6 and 2.8 Ga, occupying the east Pilbara and an unconformably overlying Archean-Proterizoic volcano sedimentary sequence called the Mount Bruce Supergroup occupying the Hamasley Basin. Pilbara Craton is one of the most important regions in the world to understand the evolution of early Earth, because the geological history is well preserved through the metamorphism of low grade. In the east Pilbara, the most conspicuous structures are broad domal granitoid complex separated by narrow synformal greenstone belts, and a model of continuous lithostratigraphy in the greenstones in which the dominant structures were produced by multi-stage granitoid diapirism. The Marble Bar greenstone belt is distributed around the Mount Edgar of granitoid pluton, and numerous hydrothermal gold veins are distributed in the greenstone near the boundary of pluton. Also base-metal veins and volcanogenic sedimentary type deposits are located in the same area. In this study, we examined the hydrothermal mineralization observed in the core samples of the Marble Bar greenstone belt, drilled at the Salgash area by the Archean Biosphere Drilling Project (ABDP).The Salgash drill hole is composed of tuff breccias with numerous fragments of black shale of 100 m in thickness, alternation of sandstone and shale of 40 m in thickness, basaltic lava and tuff of 30 m in thickness, and shale and sandstone of 110m in thickness with some sills of basalt and ultramafic rock. The rocks had been metamorphosed, and the grade is near the boundary between green schist and amphibolite facies. Low REE content (43 to 88 ppm), low La/Yb ratio (6.3 to 14.3), and high Eu/Eu* ratio (0.9 to 1.3) of the volcanic rocks are ordinal as the basaltic rock in Archean greenstone belts. On the other hand, these rocks show extremely high values of Cr (1500ppm), Ni (700ppm), Co (70 ppm), and Zn (600 ppm). The C isotopic ratios of carbonate in the volcanic rocks are around –3.8 permil. The clastic sediment sandstone and black shale show similar features, although the absolute values are slightly different. These data suggest that the clastic sediments had drived mainly from the volcanic rocks. The C isotopic ratios of organic carbon in the black shale are from –26 to –30 permil.Horizontal veins are often recognized in the clastic sediments, and are composed of quartz, calcite, sphalerite, pyrite, arsenopyrite, pyrrhotite and chalcopyrite. The C isotopic ratios of vein carbonates are from –4.6 to –5.2 permil. The S isotopic ratios of sulfide minerals are concentrated from –1.5 to +0.9 permil. The homogenization temperature of fluid inclusion in quartz vein ranges from 150 to 250 degree with the average of about 200 degree centigrade. And the fluids are composed of H2O, CO2, CH4 and C.
B8 堆積物続成過程におけるアミノ酸の高分子化とモンモリロナイトの変化

大原祥平, 掛川武, 中沢弘基

粘土科学討論会講演要旨集　(47)　104-105　2003/09/24
Publisher: 日本粘土学会
Archaeal community in the hydrothermal system at Suiyo Seamount on the Izu-Ogasawara arc

H Kasai, K Hara, T Kakegawa, A Maruyama, J Ishibashi, K Marumo, K Yamashiro, S Itahashi, T Urabe, A Yamagishi

GEOCHIMICA ET COSMOCHIMICA ACTA　67　(18)　A202-A202　2003/09

ISSN： 0016-7037

eISSN： 1872-9533
Microbial community under a hydrothermal system revealed by the analysis of water samples collected from bored holes

A Yamagishi, H Kasai, K Hara, K Yamashiro, S Itahashi, T Kakegawa, A Maruyama, J Ishibashi, K Marumo, T Urabe

GEOCHIMICA ET COSMOCHIMICA ACTA　67　(18)　A548-A548　2003/09

ISSN： 0016-7037
High pressure and temperature polymerization of amino acids suggesting a role of depth in the crust for chemical evolution

S Ohara, T Kakegawa, H Nakazawa

GEOCHIMICA ET COSMOCHIMICA ACTA　67　(18)　A349-A349　2003/09

ISSN： 0016-7037
A28 トベライト(アンモニウムマイカ)の高温高圧下での安定性

大原祥平, 掛川武, 赤石實, 中沢弘基

粘土科学　42　(3)　177-177　2003/03/28
Publisher: 日本粘土学会
ISSN： 0470-6455

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現世の海洋堆積物は主に粘土鉱物と有機物から構成され,プレートの運動により沈み込み帯から地球内部に運び込まれている.本研究では,有機物(L-アラニン)を吸着および包接した粘土鉱物(Na-モンモリロナイト)を海洋堆積物のモデルとして,地下100kmを想定した圧力2.5GPa,温度250℃から450℃で処理した結果,モンモリロナイトがトベライト(アンモニウムマイカ)に変化していることを確認した.
29-C-03 水曜海山チムニーより単離した新規硫黄還元細菌Oceanithermus sp.(分類・系統解析,一般講演)

森浩二, 掛川武, 東陽介, 中村光一, 丸山明彦, 花田智

日本微生物生態学会講演要旨集　(19)　150-150　2003
Publisher: 日本微生物生態学会
A28 トベライト(アンモニウムマイカ)の高温高圧下での安定性

大原祥平, 掛川武, 赤石實, 中沢弘基

粘土科学討論会講演要旨集　(46)　92-93　2002/09/19
Publisher: 日本粘土学会
A-50 鳴子温泉バイオマットの解析と新規硫酸塩還元菌の単離(群集構造解析3/分類・系統解析,口頭発表)

森浩二, 掛川武, 花田智

日本微生物生態学会講演要旨集　(18)　67-67　2002
Publisher: 日本微生物生態学会
C-09 伊豆・小笠原島弧、水曜海山熱水中における古細菌相の解析(農耕地生態系、水圏生態系、極限環境,第1回ポスター発表)

原来人, 掛川武, 石橋純一郎, 丸山明彦, 浦辺徹郎, 山岸明彦

日本微生物生態学会講演要旨集　(18)　129-129　2002
Publisher: 日本微生物生態学会
Preface - A special issue devoted to 50th Anniversary Symposium: Mineral Resources, Earth's Environments and Life

Y Kato, T Urabe, T Kakegawa

RESOURCE GEOLOGY　52　(2)　81-82　2002

DOI： 10.1111/j.1751-3928.2002.tb00120.x 　

ISSN： 1344-1698
Crystallization Mechanism of Calcium Carbonate by Nano-Scale In-Situ Observation(<Special Issue>Environmental Problem and Crystal Growth)

Tsukamoto Kastuo, Sorai Masao, Kakegawa Takeshi

Journal of the Japanese Association of Crystal Growth　28　(2)　61-69　2001/06/26
Publisher: The Japanese Association for Crystal Growth (JACG)
DOI： 10.19009/jjacg.28.2_61 　

ISSN： 0385-6275

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The interfacial tension, γ, between crystals and the solution plays a key role for the rate of nucleation of crystals. Attempts have been made to measure the value by measuring the incubation time for nucleation and the 1 /σ^2 where a is the supersaturation of the solution. The discrepancy of γvalues under gravity and under microgravity was interpreted as the dominant heterogeneous nucleation under gravity, whereas under microgravity homogeneous nucleation is dominant. Theγvalue can be varied by adding some impurities to the solution, which not only changes crystallization rate but also modifies the polymorphs. Since the change ofγis the result of modification of the growing/ dissolving interface, extensive AFM works have been done on calcite surface. Some AFM works and DLS works have been reviewed, so that the importance of theγvalue could be realized.
445 鳴子温泉由来バイオマットより単離した新規高温性細菌

森浩二, 花田智, 丸山明彦, 掛川武

日本生物工学会大会講演要旨集　13　215-215　2001
Publisher: 日本生物工学会
Origin of life: new problem for geosciences

Takeshi Kakegawa

JpGU News Letter　5　3-5　2000/05/01
Publisher: JpGU
Recognition of the carbon isotopic fluctuation correctable with OAE1a in the uppermost part of the Sorachi Group exposed along the Ashibetsu River, Hokkaido

ANDO Atsushi, NISHI Hiroshi, KAKEGAWA Takeshi, TAKASHIMA Reishi, SAITO Tsunemasa

Annual Meeting of the Geological Society of Japan　1998　(0)　53-53　1998
Publisher: The Geological Society of Japan
DOI： 10.14863/geosocabst.1998.0_053 　

ISSN： 1348-3935
-3.4 Ga Biogenic Pyrites and -3.1 Ga Hydrothermal Pyrites at the Princeton Gold Mine, Barberton, South Africa

KAKEGAWA T., OHMOTO H.

45　(4)　253-253　1995/08/31

ISSN： 0918-2454

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Books and Other Publications 8

地球生命誕生の謎

薮田ひかる監修

西村書店　2021/06
Astrobiology

2013/03

ISBN: 9784759815047
Evidence of the earliest life

Takeshi Kakegawa

Chemistry　2013/03
地球と生命—地球環境と生物圏進化—

掛川武, 海保邦夫

共立出版　2011
Encyclopedia of paleontology

Takeshi Kakegawa

Asakura　2010/07/01
Ecology of marine life from the view of stable isotopes

2008/10

ISBN: 9784769910831
河口汽水域を利用する魚類の食物源

伊藤絹子, 掛川武

恒星社厚生閣　2008/10/01
地球・生命ーその起源と進化

大谷栄治, 掛川武

共立出版　2005/10

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Presentations 39

The Earth made the first life

KAKEGAWA Takshi

JpGU-AGU Joint Meeting 2017　2017/05/20
Proto-arc model for ribose and nucleotide genesis: information from Isua Supracrustal Belt International-presentation

KAKEGAWA Takshi

JpGU-AGU Joint Meeting 2017　2017/05/20
Early oxygenic photosynthesis in 3.2 Ga Fig Tree Group, Barberton Greenstone Belt? International-presentation Invited

KAKEGAWA Takshi

JpGU-AGU Joint Meeting 2017　2017/05/20
Astrobiology workshop ”Search for life: from early earth to exoplanets” International-presentation

The tectonic evolution of Isua Supracrustal Belt and its implication to origin of life　2016/12/11
地球における生物の痕跡の探査

アストロバイオロジーネットワーク年会　2016/09/22
初期海洋への隕石衝突を模擬した有機物合成実験における蛇紋石の影響

竹内悠人, 古川善博, 掛川武

アストロバイオロジーネットワーク年会　2016/09/22
初期地球におけるオリゴヌクレオチドの生成に関する最近の研究と問題点

古川善博, 掛川武

アストロバイオロジーネットワーク年会　2016/09/22
２７億前のカナダシュターバー地域における海底熱水活動の影響を受けた堆積物に見出される微生物活動の痕跡

國武優樹, 掛川武

アストロバイオロジーネットワーク年会　2016/09/22
南アフリカバーバートン地域における３２億年前縞状鉄鉱層と微生物活動の痕跡

坂井健美, 掛川武

アストロバイオロジーネットワーク年会　2016/09/22
生命探査指標としてのブラックチャート：南アフリカバーバートン地域における３２億年前の例

秋廣直人, 掛川武

アストロバイオロジーネットワーク年会　2016/09/22
高温高圧におけるアスパラギン酸のペプチド化実験

岡田陽介, 古川善博, 掛川武

アストロバイオロジーネットワーク年会　2016/09/22
カナダ-オンタリオ州ポッター鉱山のVMS鉱床に見られる27億年前の微生物活動の地球化学的痕跡

小高智太郎, 掛川武

アストロバイオロジーネットワーク年会　2016/09/22
Rb/Sr ratio in lake Baikal sediment core: the new geochemicall proxy for east Asian Winter Monsoon Strength during cool climate period. International-presentation

Nara, F, Yamasaki,S-I, Watanabe,T, Tsuchiya.,N, Miyahara, H, kato.,T, Minoura, K, Kakegawa,T

Goldschmidt Conference,　2016/06/30
Formation of life’s building blocks by meteorite impacts International-presentation

Furukawa,Y, Nakazawa, H, Sekine,T, Kobayashi, T, amd Kakegawa,T

Goldschmidt Conference　2016/06/30
Proto-arc model for chemical evolution: Constraints from geological information of Isua Supracrustal Belt. International-presentation

Goldschmidt Conference　2016/06/29
Effect pH on aspartic acid peptide formations under high temperature and pressure. International-presentation

Okada,Y, Furukawa, Y, Kakegawa ,T

Goldschmidt Conference　2016/06/29
Effects of serpentine on the organic synthesis in impacts of meteorites on the early ocean. International-presentation

Takeuchi, Y, Furukawa,Y, Kobayashi, T, Nakazawa,H, Sekine,T, Kakegawa, T

Goldschmidt Conference　2016/06/29
The millennium scale monsoon cycles recorded in a sediment core from alpine Tibetan Lake International-presentation

Watanabe, T, Nara, F.W, Matsunaka T, Minoura, K, Kakegawa,T, Yamasaki, T, Tsuchiya.,N, Nakamura, T, Wang.,J, Zhu. L

Goldschmidt Conference,　2016/06/29
Geological and geochemicall study of lower Fug Tree Group in Josefsdal, South Africa International-presentation

Akihiro, N, Kakegawa, T

Goldschmidt Conference　2016/06/28
Bimodal carbon isotope compostions of organic matter at ca. 2.7 Ga Wawa Greenstone belt, Schreiber , Canada International-presentation

Kunitake,y, Kakegawa, T

Goldschmidt Conference　2016/06/28
Biosignature recorded in geochemical correlations between organic matter and Fe-bearing minerals in 3.2 Ga banded iron formations, Barberton Greenstone belt, South Africa International-presentation

Nakajima, R, Ohtomo, Y, Otake, T, Kekgawa, T, Sato,T

Goldschmidt Conference　2016/06/28
Geochemical records of microbial activities in 2.7 Ga volcanogenic massive sulfides at Potter Mine, Abitibi Greenstone Belt, Canada International-presentation

Odaka,T, Kakegawa,T

Goldschmidt Conference　2016/06/28
Geological and geochemical study of banded iron formation in the Fig Tree Group at Eureka Syncline area, Barberton Greenstone belt, South Africa. International-presentation

Sakai,T, Kakegawa,T

Goldschmidt Conference　2016/06/28
Possible Fe (II) fuled microbial ecosystem at the carbonate rich hot spring Okuoku-Hachikuro Onsen, a possible early ocean analog site International-presentation

Idei,A, Kakegawa, T, McGlynn S

Goldschmidt Conference　2016/06/28
Organic synthesis by meteorite impact International-presentation

Pre-Forum Meeting on Future Cosmochemistry for the JSPS “Science in Japan Forum 2016”　2016/06/09
ガンフリント層に多量に見いだされるパイロビチュメンが示す初期原生代地球環境 International-presentation

日本地球惑星連合大会　2016/05/24
Astrobiology International-presentation

Japan Germany Science Colloquium　2015/12/07
Department seminar International-presentation

ケベック大学セミナー　2015/09/24
日独先端科学シンポジウムの総括講演 International-presentation

JSPS日独先端科学シンポジウム　2011/11/01
Early Life International-presentation

第四回日独先端科学シンポジウム　2007/11/01
PGMとしての挨拶 International-presentation

日独先端科学シンポジウム　2006/11/02
初期地球環境と微生物活動の痕跡

日本進化学会　2006/07/30
New theory of oligin of life International-presentation

日独先端科学シンポジウム　2005/01/26
Early establishment of the phosphorous cycle International-presentation

Goldschmidt Conference　2003/09/07
Kakegawa T. (2002) Subvent Hydrothermal Processes at the Suiyo Submarine Volcano, Japan: Constraints from Sulfur Isotope Compositions of Sulfides and Sulfates International-presentation

AGU Ocean Science Meeting　2002/02
Kakegawa T.. (2001) Influence of submarine hydrothermal activities onto the Archean ocean chemistry and ecosystem. International-presentation

American Chemical Society　2001/04/07
掛川武（2000）先カンブリア紀の海洋化学進化と変動要因

地球化学会年会　2000/09
初期地球環境変動と生命進化との連動

生命の起源と進化学会　2000/03
Biological activity in the Archean oceans International-presentation

西オーストラリア大学特別セミナー　1997/08

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Industrial Property Rights 1

黒鉛を原料とするアミノ酸の製造方法

中沢弘基, 関根利守, 中沢暁, 掛川武, 古川善博, 大原祥平

特許登録4288332号

Property Type: Patent

Research Projects 37

origin of life Competitive

System: Grant-in-Aid for Scientific Research

2001/01 - Present
Elemental Cycles on the surface environment of the modern Earth Competitive

1999/06 - Present
microbial activity around submarine hydrothermal environment Competitive

System: SCF Comprehensive Joint Research (General Research)

1999/04 - Present
Interaction among atmosphere, biosphere, lithosphere and oceans on the early Earth Competitive

System: Grant-in-Aid for Scientific Research

1993/04 - Present
Assemblage of life's building molecules in the early Earth environment

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2022/04/01 - 2026/03/31
Elucidation of an unique organic matter maturation cycle in the Paleoproterozoic: potential driving force for life diversification

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: Tohoku University

2022/04/01 - 2025/03/31
Origin of ATP phosphate esters and sulfur thio-esters in early Life

McGlynn Shawn・E., 掛川武

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 基盤研究(B)

Institution: 東京工業大学

2022/04/01 - 2025/03/31
Unique phosphorous cycle on the early Earth

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2022/04/01 - 2025/03/31
Understanding biosphere-hydrosphere-atmosphere-lithosphere interactions 3.2 billion years ago with an international continental drilling program

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: Hokkaido University

2020/04/01 - 2024/03/31
Constrains on timings of cyanobacterial and eukaryotic evolutions based on innovative biomarker analyses

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Nagoya University

2019/04/01 - 2023/03/31
Role of early Earth materials for origin of life

Kakegawa Takeshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2018/04/01 - 2021/03/31

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The following big and fundamental questions were the subjects to be approached in the present study: How the building blocks of the life were prepared ?; How the protein was prepared?; How the RNA was formed? Through the course of the present project, we demonstrated that the meteorite impacts on the early oceans had significant roles to produce prebiotic amino acids, nucleotides, aldehyde and other essential molecules. These results allow us to propose that the specific geological event promoted ocean/rock/atmosphere interactions, initiating the chemical evolution for origin of life. Those prebiotic molecules were converted into “biotic” to complicated molecules using the environments and minerals on the surface of the early Earth. Our experiments demonstrated that ribose, peptides, and nucleotides can be formed under the simulated Earth environments. We are also proposing the origin of life had never happened without the uniqueness of the early Earth and earth materials.
Deciphering the evolution history of volatile elements toward the formation of the water-planet, recorded in lunar potassium feldspar

Hashizume Ko

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Ibaraki University

2017/04/01 - 2020/03/31

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This project aims at deciphering the origin of nitrogen trapped in Moon rocks. A novel ion-microprobe analytical technique that enables detection of ammonium-form nitrogen concentrated in potassium-bearing minerals was developed. To enhance the detection sensitivity of nitrogen, carbon ions were implanted to the rock minerals. A high gain of cyanide ions was confirmed from terrestrial potassium-feldspars with known nitrogen concentrations. Compatible nitrogen ion intensities were confirmed in potassium-feldspar from lunar meteorites. We estimate nitrogen concentration of approximately 100 ppm in this specific mineral, which is much higher than the bulk concentration of nitrogen, generally of the order of 1 ppm.
Early Earth made and build essential biomolecules

Takeshi Kakegawa, TANIGUCHI TAKSHI

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2015/04/01 - 2018/03/31

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We performed following series of experiments to approach essential problems for origin of life: (1) Simulation experiment for meteorite impact on the early oceans, (2) experiments for ribose and nucleotide formations assuming early oceanic and evaporitic environments, and (3) biotic-like peptide formation assuming inside of Hadean marine sediments. We were successful to form various amino acids and pyrimidine nucleobases by experiment (1). Ribose was selectively stabilized and nucleotide was formed using Luneburgite by experiment (2). We were also able to form aspartic acid peptides and methionine peptides under high P and T conditions, which were the same range of deep marine sediments. In particular, prebiotic sulfur cycle, which is identical biotic sulfur cycle, was realized during the methionine peptide formation. All results suggest how dynamics of the early Earth were important to promote chemical evolution for origin of life.
Challenge to the formation of prebiotic RNA on mineral templates

Furukawa Yoshihiro, KAKEGAWA TAKESHI, NAGASE TOSHIRO

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2015/04/01 - 2017/03/31

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This study challenged the formation of oligonucleotides on mineral templates. Gypsum and calcite were used as the template mineral since they are ion crystal that potentially presented on the early Earth. Four kinds of adenosine nucleotides were investigated as the monomer of the oligomerization experiments. As the results, oligonucleotides were formed on gypsum template and glass template. However, the reproducibility of the results and the effects of template remain unclear. Thus, additional experiments are conducted. Further, a borophosohate mineral, luneburgite, was investigated as the source of phosphorus in phosphorylation of nucleoside and found that this mineral serves phosphate effectively and promote the formation of nucleotide in a potential prebiotic environment. This work was published in Angwandte Chemie International Edition as a very important paper.
Prebiotic organic world produced by early Earth environments

KAKEGAWA Takeshi, FURUKAWA Yoshihiro, SEKINE Toshimori

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2012/05/31 - 2015/03/31

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The purposes of the present study are to perform various experiments for formations of prebiotic organic molecules. We consider that water-rock interaction on the early Earth (including meteorite impact, diagenesis of marine sediments etc.) had played important roles for the prebiotic organic formations. We performed simulating experiments for those water-rock interactions, besides installing state-of-art analytical instruments. We were successful to synthesize various amino acids, nucleic acids, and peptides under high P and T conditions. In addition, selective stabilization of ribose was successful in highly alkaline conditions. Those new data are valuable to promote our knowledge for origin of life.
Identification of primary producers in the early oceans

KAKEGAWA Takeshi, HASHIZUME Ko, NAGASE Toshirou

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2012/04/01 - 2015/03/31

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The purposes of the present study are to constrain biological primary producers in 3.8, 3.2, and 3.0 Ga oceans. To approach the purpose, we performed geological surveys in Isua (Greenland), Barberton (S. Africa), and Steep Rock and Lumby Lake (Canada). Besides the detailed geological data, mineralogical and geochemical data suggest that cyanobacteria were the primary producers at least since 3.0 Ga. In addition, chemoautotrophic and heterotrophic bacteria, whose activities were supported by cyanobacteria indirectly, were also active in deep sedimentary basin. We also discovered new evidence for trace of the earliest life in rocks from Isua. This discovery was broadcasted widely through various media. Other results were reported at the major international conferences. Some papers are in reviews at major international journals.
Biomolecular evolution based on chiral chemistry under oceanic impact of meteorite

SEKINE Toshimori, FURUKAWA Yoshihiro, KOBAYASHI Takamichi, KAKEGAWA Takeshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Hiroshima University

2012/04/01 - 2014/03/31

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Recent studies suggest that there were oceans about 4 Gya and that the Earth might be subject to violent meteorite impacts (called LHB). Experimental study confirms the formation of biomolecules under such environments and prebiotic carbons in the sedimentary rocks have been found. Amino acid is a basic biomolecule for the origin of life and protein consists of L-amino acids. We investigated the chiral changes experimentally.The present experimental results on valine imply that impact effects on the chiral chemistry lead to an increase of D-enantiomer only in calcite and that L-enantiomer enrichment will occur little by impact.
High temperature and pressure experiments to synthesize rarely-formed organic molecules

KAKEGAWA Takeshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2010 - 2011

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Formose reactions are responsible for ribose formation. The unique technique was invented in the present study to identify intermediate products and final products through the formose reactions. Using this new technique, it is found that ribose-borate complex is more stabilized compared to other pentose-borate complex. This yields selectively survived ribose in the alkaline and slightly heated solutions. In addition, this study answers a question as to why RNA chosen ribose.
Production of amino acids and peptides on the early Earth

KAKEGAWA Takeshi, SEKINE Toshimori, OBA Masahiro

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2009 - 2011

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Production of an amino acid and various organic molecules were successful by shock experiments simulating meteorite ocean impact events. High productions of ammonia and hydrogen cyanide were confirmed by impact-plume-simulation experiments. Polymerization experiments of amino acids were also successful : successful polymerization of alanine and glycine at 5 GPa was surprising results. Best presentation awards were granted to this result. In addition, variety and unique peptides were formed under high pressure and temperature conditions.
Relationship between photosynthesis and banded iron formations at the early Archean

KAKEGAWA Takeshi, HASHIZUME Ko, OBA Masahiro

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2009 - 2011

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Diagenetic chromium oxides were newly found in banded iron formations at 3. 2 Ga Barberton Greenstone Belt, South Africa. Oxygenisotopeanalyses of chromium oxides suggest oxygen from photosynthesis was responsible for oxidation and precipitation of chromium. By studying banded iron formations at Lumby Lake area, Canada, many geological samples recoded the evidence of oxygenic photosynthesis and activities of chemoautotrophs. In particular,"chemoautotrophic" rocks were found to be formed under t he influence of submarine hydrothermal activities. In other words, photosynthesis was widespread at the surface oceans and bottom was dominated by chemoautotrophs at 3. 0 Ga.
有機分子の起源:微惑星・隕石海洋爆撃による大量生成説の検証実験

中沢弘基, 関根利守, 掛川武, 小林敬道

Offer Organization: 日本学術振興会

System: 科学研究費助成事業基盤研究(B)

Category: 基盤研究(B)

Institution: 独立行政法人物質・材料研究機構

2009 - 2010

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生命起源に関する「有機分子ビッグバン説」(中沢、2006*)を実験的に証明するのが本研究の第一の目的である。そこで(1a)隕石海洋衝突を模擬した衝撃実験と、(1b)衝突蒸発雲を想定したガスー鉱物反応実験を行った。第二の目的は、生成したアミノ酸がタンパク質になる過程は海洋ではなく海底堆積物中で進行した、とする「生命の地下発生説(中沢、2006*)」を証明するために、(2a)グリシン、アラニンなど単独のアミノ酸および(2b)複数アミノ酸混合物を地下の高温高圧に相当する条件で処理する実験を行った。(1a)はNIMSの衝撃圧縮実験装置を用いた衝突再現実験、(1b)は東北大学における衝突蒸発雲内部を模擬するガス・固体反応実験である。それらの生成物は東北大学のLC-MSとGC-MSを用いて分析され、アミノ酸やカルボン酸など既に報告した分子種に加えて、低分子有機分子(メタン、エタン、ベンゼンなど炭化水素、およびメタノールなど)が生成されることが明らかとなり、衝突蒸気雲内部での反応がかなり解明された。 (2a)の実験は、NIMSのベルト型高圧発生装置を用いて行われ、いかなる触媒も用いずにグリシンやアラニンが5量体までペプチド化すると共に、それらのアミノ酸やベプチチドが安定に存在し続けるためには堆積物中にアンモニアが多量に存在する環境が必要であることが判明した。この条件は40～38億年前にはあり得るので、(1a),(1b),(2a)の一連の研究によって、生命の起源に至る化学進化の道筋が相当に明らかとなった。(2b)の実験は東北大学のオートクレープおよびピストンシリンダー高圧発生装置で行われ、2種以上のアミノ酸の混合物では、単純系で生成されなかったペプチドが高温高圧状態で生成されることが明らかとなった。これらの成果は、論文として投稿中であり、国際学会(AbSciConやGoldschmidt会議など)ではすでに公表された。(*中沢弘基「生命の起源・地球が書いたシナリオ」新日本出版2006)
原始地球における有機分子の起源:13C固体炭素を用いた衝撃実験による検証

中沢弘基, 関根利守, 掛川武

Offer Organization: 日本学術振興会

System: 科学研究費助成事業萌芽研究

Category: 萌芽研究

Institution: 独立行政法人物質・材料研究機構

2007 - 2008

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地球に海が生じた後、40〜38億年前頃激しかった隕石の海洋爆撃を想定し、隕石成分の代表である金属鉄(Fe)と炭素(C)、海洋主成分の水(H_2O)および当時の大気主成分の窒素ガス(N_2)をカプセルに詰め、それを標的とした衝撃実験を行い、生成物を回収し、生成した有機分子を液体クロマト・質量分析計(LC-MS/MS)で検出・同定した。その結果、グリシン(アミノ酸)および炭素鎖の長さの異なるアミン、カルボン酸など、11種の生物有機分子の生成を確認した。本研究により、冥王代末期の地球史的イベントである隕石・微惑星重爆撃(LHB)により生物有機分子が容易に生成したであろうことが実験的に証明された。地球の海と大気と隕石成分が衝撃により激しい化学反応を生じて、生命起源の素となる生物有機分子を生じせしめたと推定される。ミラーの実験として良く知られている、大気中の雷放電によってアミノ酸などが生じたとする説は、大気がメタンやアンモニアなどの還元的分子で構成されていたことが前提となっていたが、1970年代後半に、冥王代の大気はむしろ酸化的であったことが判り、その根拠を失っていた。本研究は、大気が非還元的であっても海洋と隕石成分の反応で有機分子が多量に生成するであろうとする「有機分子ビッグバン説(中沢)」の妥当をが実証し、地球史的に合理的な新たな有機分子起源説を日本から発信することになった。Nature Geoscience誌に発表した論文は国内外の研究者および一般マスコミの大きな関心を呼んでインタビューを受け、日米新聞各紙やNHKニュースで大きく報道された。
Bio-molecule formation by oceanic impact events on the early Earth

KAKEGAWA Takeshi, NAGASE Toshirou, NAKAZAWA Hiromoto, SEKINE Toshimori

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2006 - 2008
International project to investigate the world-oldest biogenic graphite

KAKEGAWA Takeshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2005 - 2007

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The main purpose of this study is to investigate the newly found outcrops in the Isua Supracrustal Belt in Greenland and accumulate more evidence for activities of the earliest life with collaborating with Prof. Rosing at Copenhagen University. The world-oldest rocks, 3.8 Ga, are distributing in this Isua Supracrustal Belt. We performed intensive geological surveys during summers of 2005, 2006 and 2007. Newly found rocks contain abundant graphite. Detailed geochemical data suggest that such graphite was biogenic in origin. In addition, detailed TEM observation indicates a unique texture in graphite, which suggests that graphite was not formed later processes, thus biogenic in origin. In addition, we also found nano-sized graphite in magnetite crystals in banded iron formations; the first report from banded iron formations in Isua. This discovery further suggests that graphite were ubiquitous in the 3.8 Ga oceans. We also performed geological surveys in the Steep Rock area in Canada, in order to compare the Isua's results to younger rocks. The oldest organic molecules indicating activities of oxygenic photosynthesis were found through the course of the present study. We also proposed that nano-sized metallic oxides incorporated the organic matter can be used as a new type of biomarker to indicate the activity of oxygenic photosynthesis.
海底熱水系における分子レベルでの微生物・鉱物相互作用

掛川武

Offer Organization: 日本学術振興会

System: 科学研究費助成事業萌芽研究

Category: 萌芽研究

Institution: 東北大学

2005 - 2006

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鉱物と始源生物の関係は古くから問われている課題であるが、未解決である。本研究では、海底熱水活動で無機物沈殿と化学合成細菌微生物マット形成が同時に起こっている試料を採集し、そこでの微生物生態層解析を遺伝子情報および酵素活性情報から規定することを目的とした。この解析により、そこでの微生物がどの無機元素を必要とするか限定される。更に無機物、金属-有機錯体、微生物-無機物界面をナノスケール・分子レベルで観察・分析を行うことも目的とした。それによって始源的生物が鉱物をうまく活用し生息している様子を具体化してゆくことを更なる目的とした。本研究を推進するためにJAMSTEC調査船による航海申請を行った。過去に掘削を行った南部マリアナの航海を行った。外国旅費は主に海域に移動するために用いられた。先年度調査を行った既に海底に設置されている海域からはずれ更に新しい海域に調査範囲を広げた。微生物が関与してマンガンを沈殿させる様子などが観察された。東北大学に試料を持ち帰り、その後試料は環境制御型電子顕微鏡、透過型電子顕微鏡などで観察し、様々な有機無機複合体を見いだした。これは昨年度採集された水曜海山の試料と合わせて行った。特に透過型電子顕微鏡でアモルファス鉱物中の生体必須元素の濃集形態が明らかになり、微生物との界面の観察が行われた。東北大学に新たに設置されたLC-MS/MSを用いて微生物由来金属-有機錯体(金属クラスター)を特定する分析を行った。分析条件の設定が予想外に困難であったが、当初目的にしたデータは見いだしたが、追加試験を行う必要はある。FT-IR、ラマン分光分析からも間接的にも有機金属錯体の存在がサポートされ,それらの成果は論文化の作業が進められている。
Generation of polypeptide and polynucleotide in the upper crust of the early Earth

KAKEGAWA Takeshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2003 - 2005

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The main purpose of this study is to synthesize and polymerize amino acids and nucleotide experimentally simulating the early Earth conditions. In particular, roles of meteorite impact for the amino acid generation are emphasized in this study in addition to roles of high pressure and temperature conditions for polymerization of amino acids. Various experimental apparatus were used in this study including shock-induced instruments and high pressure autoclaves. Analyses were essentially made by HPLC purchased through this project. Generation of ammonia, which are nitrogen sources for the amino acids was experimentally confirmed first time. Vaporization of most meteorite materials were also confirmed suggesting that the post impact plume, which may have been reaction center for the amino acid synthesis, has been easily produced. Polymerization of amino acids is also confirmed to proceed under high P and T conditions up to 9-peptide, which is the world record for the synthesis from single amino acids. It is also found that the importance of sulfide minerals for the polymerization of amino acids. Thermal stability and role of phosphate minerals for nucleotide is also confirmed in this study. These results lead to propose new chemical evolution model for the origin of life. Through this study, two text books were published contributing public outreach.
Joint International Research Project on Free Oxygen and Biomarker on the Early Earth

NEDACHI Munetomo, KAKEGAWA Takeshi, NARAOKA Hiroshi, HAYASHI Kenitiro, KATO Yasuhiro, NEDACHI Yoko

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: Kagoshima University

2002 - 2004

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The objectives of this research are to understand the distributions of Archean microbes in space and in time, to understand in what geochemical environment the microbes inhabited, and to study the geophysical controlling factors on the co-evolution of life and environmenta. In 2004, we drilled another hole to collect the core which cuts through the Tumbiana Formation (2.76Ga). We had failed to obtain this formation in the 2003 drilling project. The American research group (Deep Time Drilling Project) collaborated us in this year's project, along with our collaboration groups of NASA Astrobiology Institute, University of Western Australia and Geological Survey of Western Australia. After the observation under optic and electron microscope, these cores were examined for the isotopic compositions of sulfur and carbon, and were extracted the organic compounds to examine the chemical fossils of microbes. Archean atmospheric and oceanic environment were discussed from the geochemical data. We also focused into paleomagnetism, assumed that geomagnetic field should play an important role to bio-activity. The obtained results have been presented at international conferences as well as domestic conferences. The number of presentation from 2002 to present have been 21 for international conferences including AbSciCon (San Francisco), IGC (Firenze) and AGU (San Francisco), and 18 for domestic conferences. One of the chief contribution of this project might shedding light on the history of development of microbes. Out results suggest that iron-bacteria and methanogen might be the dominant microbes around 3.46Ga, and the microbes might become diversified around 2.77 Ga including methanogen, methanotroph, sulfate-reducing bacteria and cyanobacteria. It also suggests that eukaryote inhabited at that era. The second is the discovery of the oldest geomagnetic field by the Earth's dinamo at 3.46 Ga.. The microbial diversity around 2.77 Ga ago could strongly relates to the increasing geomagnetic field.
Constraints on ancient ocean chemistry based on the geochemical study of 3.8 Ga Isua Supracrustal Rocks.

KAKEGAWA Takeshi, NAKAZAWA Hiromoto

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2002 - 2004

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This scientific proposal has been approved in 2003. The main purpose is to conduct geological survey for the Isua area in Greenland. In this area, the oldest fragments of the, earth crust is found : they were formed at 3.8 Ga on the contemporary ocean floor. The main scientific goal is to constrain the ocean chemistry at 3.8 Ga through the geochemical studies of the Isua rocks. In addition, finding new evidence for the early life is also the subject. From 2003 to 2004, detailed field surveys were performed. Collected rocks were analyzed by several geochemical methods. New results to constrain the phosphorous and carbonate chemistry were obtained. New evidence for the earliest life was also discovered through the course of this study. These were very fruitful results and very important findings. Some results were already published on the scientific journals. Studying modern analogue is additional subjects for this study. Submarine and terrestrial hot springs were chosen for this purpose. Some data obtained from the field was used for experiments to demonstrate the early earth environments in the laboratory.
Biological activities at the Archean submarine hydrothermal environments

KAKEGAWA Takeshi, NAGASE Toshiro

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2001 - 2003

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Hydrothermal origin of life on the Archean seafloor is becoming a popular theory, besides the idea that the evolution of early biota took place at the submarine hydrothermal environments Abundant submarine hydrothermal sediments have been found in the Archean strata and there exists possibility that remnants of early biota and chemical fossils of their ecosystem were still preserved in these sediments. The main purpose of this study is to identify the remnants of early biota and their ecosystem based on the geological and geochemical ways. In this study, detailed geological surveys were conducted in two areas : the 2.7 Ga Abitibi Greenstone Belt and 3.2 Ga Pilbara Blocks in Australia. Other samples related to Archean submarine hydrothermal activities and modern hydrothermal activities were also subjects for the chemical analyses in this study. The followings are the notable findings from this study : specific hydrothermal alterations by carbon dioxide-rich fluids and mobilization of phosphorous from oceanic crust, age specific activity of methane-related biota and their association with magmatic activity and metal enrichments in organic matter by hydrothermal reaction. New ecological energy exchange system was also found in the modern hydrothermal sediments and its links to Archean ecosystem was also proposed. These achievements were already published in the several international and domestic journals, and also reported at international conferences as invited talks. New theory of biological evolution associated with the contemporary magmatic activity is also proposed from this study.
Behavior of volatile components and mechanism of ore formation in the magmatic-hydrothermal system

HAYASHI Ken-ichiro, KAKEGAWA Takeshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2000 - 2002

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During the solidification of hydrous granitic magma, water of very high salinity separates from the magma. The magmatic water contains volatile components such as CO_2 and H_2S. Since concentration of dissolved metallic ions in magmatic water is rather high, it behaves as an ore-forming solution. In this study, ore deposits that have genetical relation with magmatic water are studied. The skarn-type magnetite deposit at the Beni Bou Ifrour mine, northeastem Morocco, is the one of the major iron deposits in northern Africa. The skarn ore develops between limestone and microgranodioritic intrusions. The genetical relationship between skarn and granodiorite has been argued. The result of K-Ar dating shows that age of skarn mineral is approximately same as that of granodiorite; this agreement suggests ore-forming solution of this deposit was magmatic water that derived from granodiorite. Data obtained from fluid inclusions show very high temperature, 〜500℃, and very high salinity, 〜75 wt% equivalent NaCl. Oxygen isotope values of skarn minerals suggest that water of magmatic origin precipitated skarn minerals. Therefore, magmatic water of high temperature and high salinity was responsible for the transport of large amount of iron during the formation of magnetite deposit. Oxygen isotope values of manganese silicate minerals from the metamorphosed bedded type manganese deposit at the Noda-Tamagawa mine, northeastern Japan, were analyzed. Since this manganese deposit is hosted in the roofpendant just above the granitic body, evidence of magmatic water probably recorded in manganese minerals. However, oxygen isotopic equilibrium has not been attained among manganese minerals of closely associated. This suggests that amount of metamorphic fluid during contact metamorphism has been very small.
Archean biological activity evolved with environ mental changes of the earth's surface inferred from biomarkers and stable isotopic compositions

NARAOKA Hiroshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: TOKYO METROPOLITAN UNIVERSITY

2000 - 2002

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Photoautotrophic organisms evolving O_2 were already active as early as 3.5 Ga ago from studies of microfossils, and chemical fossils such as carbon isotopic compositions of organic matter. Eukaryotic biomarkers were also reported to be present in the Archean ocean. The popular theory, however, has been that the evolved O_2 was consumed to oxidize the earth's terrestrial environment and the atmosphere should be essentially O_2-free until 2.2 Ga ago. The Jeerinah Formation ( 2.7 Ga) in the Hamersley Basin, Western Australia is mainly composed of organic carbon-and pyrite-rich black shales. In this study, using a drilling core section, chemical and isotopic compositions of sedimentary rock samples of the Jeerinah Formation were determined to characterize biological activites involving redox conditions of the ocean. The Jeerinah shales contain high amounts of organic carbon (up to 8 wt%) and pyrite sulfur (up to 7.5 wt%). The isotopic composition of organic carbon varies systematically through the stratigraphic section from -45 to -35% in δ^<13>C. The carbon isotope excursion could be explained by two-endmember mixing of organic matters between isotopically heavy component produced by normal photoautotrophs and light component produced by methane-assimilated heterotrophs. The carbon isotope excursions are accompanied with sulfur isotope excursions, from -10 to +10% in δ^<34>S. Sulfur isotope fractionation should be more than 20% by sulfur-reducing bacteria (SRB). The organic carbon contents are positively correlated with the nitorogen contents (N/C=0.006 by atomic). Bulk nitrogen isotopic composition falls mainly in a range from 0 to +5% in δ^<15>N ; these values are similar to those of common organisms in modern oceans. The shale with highest organic carbon content has a δ^<15>N value -%, probably indicating nitrogen fixation by cyanobacteria as a primary producer. However, the shale has an intermediate δ^<13>C value (-40%), possibly due to a contribution from chemoautotrophs or heterotrophs such as methanotrophs and SRB. Molybdenum concentrations are positively correlated with organic carbon content except two samples. The Mo could be weathered under oxic condition, and fixed in organic materials. A negative Eu shift is observed during positive shifts in δ^<13>C of organic carbon and δ^<34>S of sulfide. Such element behaviors suggest that weathering, transportation and fixation mechanism of Mo and REE should be affected under oxic condition. In contrast to a currently popular view that Archean oceans were entirely anoxic the results of our study suggest that the redox structure and biological activity in the Hamersley Basin were much more variable.
リン酸塩ノジュールの成因と古堆積環境の復元

掛川武

Offer Organization: 日本学術振興会

System: 科学研究費助成事業奨励研究(A)

Category: 奨励研究(A)

Institution: 東北大学

1999 - 2000

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海洋中リンの堆積物への移動過程、さらに再濃集(リン酸塩ノジュール形成)過程を研究する事により、地質時代の海洋環境を再現する事が本研究の目的である。本年度は時に原生代前期試料および三畳紀/二畳紀境界試料、中期白亜紀試料(OAE層序:Ocean Anoxia Event)について、研究を行った。従来は『海洋が、酸化的還元的と2層に別れ、低層水にリンが濃集し、湧昇流活発化に伴いリンが浅海性堆積物に濃集した』とする説が有力視されていた。昨年度の研究成果から、『海洋2層構造崩壊よりも、地球環境温暖化、それに伴う生物生産向上がリン酸塩ノジュール形成のきっかけを作った』と言う結論を得た。この考えを更に発達させる為、生物活動、大気海洋環境変動、リン酸塩鉱物形成との関連を明らかにすべく、安定同位体、EPMA鉱物分析などを集中的に行った。ICPを用いたMo,Uなどの分析、元素分析計による炭素、硫黄含有量測定、レーザーマイクロプローブ法による黄鉄鉱硫黄同位体分折、炭素同位体分折なども行った。特に後期原生代の縞状鉄鉱層の研究を組み入れた事で、(1)海洋中のリンは鉄水酸化物(縞状鉄鉱層)沈澱に伴ってより、(2)むしろ縞状鉄鉱層の堆積に触発された微生物活動により、堆積物に濃集し、続生作用によって再濃集しリン酸塩ノジュールを作る事が具体化された。縞状鉄鉱層形成と湧昇流との関係が議論されてきただけに、この研究で得られた説が従来説より正しい事の裏付けができた。これらの成果に関し、国内(地球惑星関連合同大会など)及び外国(NASA Astrobiology Conferenceなど)の学会において成果報告を行った。後期原生代の成果の一部は投稿論文(Viva Origino)として既に出版された。その他の成果も、論文査読中もしくは、投稿準備中であり、概して成果の多い研究であったと自己評価している。
Evolution of the Atmosphere, Ocean, Crust, and Biosphere

NEDACHI Munetomo, NEDACHI Yoko, NARAOKA Hiroshi, HAYASHI Kenichiro, KAKEGAWA Takeshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A).

Category: Grant-in-Aid for Scientific Research (A).

Institution: Kagoshima University

1998 - 1999

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The primary objective of this project is to develop a quantitative model for the evolution of atmospheric oxygen and its connection to the evolution of organisms during the period between 3.5 Ga and 0.5 Ga, from detailed geochemical investigations of a variety of rocks formed during this period, including banded iron formations, paleosols, uraniferous quartz pebble conglomerates, shales, carbonates, and volcanic rocks. Field investigations of these types of rocks were carried out in South Africa, Namibia, and Australia in the summers of 1998 and 1999. Various types of geochemical data obtained in this project are all consistent with the our model for the early development of an oxygenated atmosphere and of a diverse biosphere. The following are brief summaries of new findings. The oldest paleosol sections that show a significant loss of Fe are those developed on the 2.8 Ga Mt. Roe basalt in western Australia. Nedachi et al., however, strongly suggest that the loss of Fe from the Mt. Roe paleosols was caused by CH4-bearing hydrothermal solutions with temperatures of 〜200 - 〜100℃, rather than by the surface water during soil formation. The advocates of the CWKH model have adapted the interpretation that the grains of uraninite and pyrite in pre-2.2 Ga quartz-pebble conglomerates are of detrital origin. Ono et al. (Paper #4) report the results of a small-scale, detailed analyses of textures, chemical composition, and isotopic composition of a variety of minerals in 〜2.4 Ga quartz-pebble conglomerates from the Elliot Lake district, Canada. Based on new experimental data on the dissolution kinetics of uraninite, Ono and Ohmoto conclude that typical grains of uraninite can survive for more than 1000 years under the present atmospheric condition. Therefore, the presence or absence of detrital grains of uraninite may not be used to constrain the atmospheric pO2 level. The same conclusions were obtained from the geochemistry of the Archean shale, increased Fe3+/Fe2+ ratios in the rims of pillow lava, origins of BIF, and evidence in BIFs for the early development of an oxygenated atmosphere
高温熱水系での熱水の沸騰に伴う重金属の挙動

林謙一郎, 掛川武

Offer Organization: 日本学術振興会

System: 科学研究費助成事業萌芽的研究

Category: 萌芽的研究

Institution: 東北大学

1998 - 1999

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熱水に溶存していた金属は、沸騰に伴い液体中に留まるという従来の考えでは説明できない現象が、流体包有物の分析から明らかになりつつある。一部の揮発性金属が沸騰時に水蒸気中に移動する可能性が高い。昨年度に引き続き、インコネル625製の反応容器(内容量〜150ml)に気相と液相を同時に採取するためのバルブ類を取り付けた装置により、350-450℃で熱水実験を行った。10%NaCl水溶液を出発溶液とし、あらかじめ100-1000ppmのSnおよび55-550ppmのZnの塩化物を加え、高温条件下で10時間程度保ち、液相と平衡状態にあると思われる水蒸気相を凝集させて採取した。水蒸気のサンプリングはニードルバルブの操作により穏やかに行った。試料溶液中のSn,Zn,Naを原子吸光法で、Cl濃度をイオンクロマト法により測定した。SnおよびZnの水蒸気中の濃度は、450℃でそれぞれ0.01ppm,0.5ppm程度となる。昨年行ったCuの結果を合わせて考察すると、各種元素の蒸発度(C_<vapor>/C_<liquid>)はCu>Zn>Cl>Na>Snの順となり、とくにCuの蒸発度が大きい。実験結果を、斑岩型鉱床近傍で採られた流体包有物の分析から報告されている気/液両相への重金属の分配値と比較すると、Cuの分配係数がZnやSnより1桁以上高くなるのは同様の傾向である。流体包有物(600-700℃)より求められる分配係数は、本研究で行った温度範囲(350-450℃)よりも2桁程度高く、温度効果が非常に大きいが、分配傾向は本実験の結果と一致し、本研究の妥当性を示す。
Establishment of the stable isotopic stratigraphy of Banded Iron Formations

HAYASHI Ken-ichiro, KAKEGAWA Takeshi, TSUKAMOTO Katsuo, OHMOTO Hiroshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)

Category: Grant-in-Aid for Scientific Research (C)

Institution: Tohoku University

1996 - 1997

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Banded iron formations (BIFs), bedded manganese deposits, and silica sinters are the typical examples of chemical sediments that possess clear banding texture. These sedimentary rocks have precipitated on seafloor or subaerial surface, from seawater or hydrothermal solutions with the decrease of solubilities of silica, iron, and manganese in solutions. Variation of stable isotopic compositions of oxygen, carbon, and sulfur in these banded chemical sedimentary rocks have been measured to clarify their genesis. 1.Newly developed CO_2-laser microprobe fluorination technique was applied to the Brockman Iron Formation, Hamersley basin, Western Australia, to investigate submillimeter scale oxygen isotopic compositions of quartz both hosted in chert and iron-oxide mesobands. Our data show that delta^<18>O values of BIFs vary between 16.0 and 23.0*, on the contrary to the previous studies that BIFs are isotopically homogeneous. The wide variation of delta^<18>O probably suggests that hydrothermal activities have been responsible for the formation of Hamersley BIFs. 2.Isotopic values of organic and carbonate carbon in shale macrobands of the Marra Mamba Iron Formation, Western Australia were measured. The very low delta^<13>C values of organic C,-41.0--37.1*, suggest the activity of the metanogens and metanotrophs in the ocean. The delta^<13>C of dissolved bicarbonate in seawater estimated from carbon isotopic compositions of carbonate was delta^<13>C=--12*. This low value, compared to that of the modern marine HCO_3^- (--1.0*), was also explained as the results of a carbon-cycle system affected by the activities of metanogens and methanotrophs. 3.The delta^<18>O values of quartz in silica sinter from the Kitano-oh gold deposits, and those of manganese silicate minerals from the metamorphosed bedded manganese deposits of the Noda-Tamagawa mine were measured. The origin of hydrothermal solutions is discussed.
Roles of Hydrothermal Processes in Biological Evolution

OHMOTO Hiroshi, ONO Shuhei, MOCK Robin L, YAMAGUCHI Kosei, KUMP Lee R, OCHIAI Ei-ichiro, MINTER W.E.L, BARNES Hubert L, NEDACHI Munetomo, KAKEGAWA Takeshi, HAYASHI Ken-ichiro

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for international Scientific Research

Category: Grant-in-Aid for international Scientific Research

Institution: Tohoku University

1995 - 1996

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The main objective of this research project was to understand the causes for major biological events in the early Earth, especially the first appearances of eukaryotes around 2 billion years ago and of large marine fauna around 550 million years ago. This objective was mostly pursued from systematic geochemical investigations of organic matter, minerals and rocks in about 1000 rock specimens that were collected during our field surveys in 4 areas : (A) the southern Ontario district, Canada (2.8-1.8 Ga sequence), (B) the Burin Peninsula, Newfoundland, Canada (570-520 Ma sequence), (C) the Normandy district, France (600-500Ma sequence), and (D) the Kaapvaal Craton, South Africa (3.0-2.0 Ga sequence). Our investigations have resulted in the following major findings : (1). According to a currently popular theory, the first major division of biological species (Eukaryotes, Bacteria, and Eubacteria) were caused by a dramatic rise of the atmosphericO_2 around 2.0 billion years ago. However, we have discovered various lines of geochemical evidence suggesting that the major division of biological species and the development of an oxic atmosphere had already taken place by 3.0 billion years ago. (2). "The great biological explosion" of around 550 million years ago was probably caused by the global changes in the ocean water chemistry (e.g., an increase in the phosphate flux) and climate. (3). The major changes in the ocean water chemistyr that affected the biological activity in ocean through geologic time were probably caused by the changes in the geographical configuration of continents (e.g., breaking of super continents) and in submarine hydrothermal activity in mid ocean ridges. These changes were in turn caused by changes in the convective patterns in the mantle. Some of the results from our investigations have already been presented at national and international scientific meetings (about 25 presentations). Five papers have been published (or in press) in major international journals, and about 20 more papers related to this project are in preparation.
Surface Enviroments, Biological Activities and Elemental Cycles of the Early Earth

OHMOTO Horoshi, KAKEGAWA Takeshi, NARAOKA Hiroshi, HAYASHI Ken-ichiro

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Specially Promoted Research

Category: Grant-in-Aid for Specially Promoted Research

Institution: Tohoku University

1991 - 1994

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The current "dominant" theory concerning the surface environments, biological activity, and global geochemical cycles of elements of the early Earth holds that they were quite different from those in the present time. The main objective of our research was to develop a new perspective of the Earth by critically examining this "dominant theory" and a new theory proposed by Ohmoto. The approaches taken in this research project, in contrast to researches carried out by previous investigators, were more detailed, systematic, and multidimensional studies of the geochemical nature of a large number of samples of soils, sedimentary rocks, igneous rocks, metamorphic rocks and ore deposits formed during the period of 3.8 to 1.8 b.y.ago in many different regions in the world. Our geochemical investigations have resulted in many important discoveries concerning the biological and chemical evolution of the Earth : (1) the oxygen-producing photosynthetic plants and organisms have been active in ocean and on the continents since at least 3.5 b.y.ago ; (2) sulfate-reducing bacteria have been active in ocean since at least 3.8 b.y.ago, and methanogenic and methanotrophic bacteria since at least 2.8 b.y.ago ; (3) the atmosphere has been oxygen-rich since at least 3.5 b.y.ago ; (4) prior to -2.3 b.y.ago, the CO_2 content of the atmosphere was about 100 times greater and the surface temperature was about 30ﾟC higher than today ; (5) large-scale, deep, and anoxic basins developed periodically during the 2.8-2.3 b.y.period, and the basins became important sites for the accumulation of heavy metals ; (6) marine and terrestrial biota playd a major role in the geochemical cycles of C,O,S,Fe, U and many other elements in the early Earth in much the same ways as in today's Earth. We have developed a new theory that the biological and chemical evolution of the early Earth was more highly accelerated than previouly recognized, and that the elemental fluxes among the earth's various reservoirs (core, mantle, crust, ocean and atmosphere) have been at a steady state since at least -3.5 b.y.ago.

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Social Activities 10

Exhibition of traces of the oldest life from Greenland Isua

2015/07/07 - 2016/09/04
出前授業

2007/09/01 - 2007/09/02

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大船渡高校に置ける体験大学講座
出前授業（宇都宮東高校）

2020/11 -
出前授業（酒田南高校）

2020/05 -
出前授業（大曲高校）

2019/11 -
出前授業（盛岡第三高校）

2018/10 -
雑誌「公研」インタビュー記事

公研10月号、２０１７年

2017/10 -
NHKスペシャル

2012/10 -

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火星大冒険
福島県立東高校体験講座会

2011/10 -

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高校生の大学講義体験
日独先端科学シンポジウムプレスリリース

2007/01/20 -

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日独先端科学シンポジウムの内容と成果が日本学術振興会からプレスリリースされホームページ掲載された

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Media Coverage 12

Cosmic Front on NHK Myself

NHK

2018/07

Type: TV or radio program
ヤクルト機関紙「ヘルシトス」での研究紹介

ヤクルト　巻頭インタビュー

2017/07

Type: Newspaper, magazine
最古の生命の痕跡発見

NHK

2013/12/09

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ガリレオX

BSフジ

2012/05

Type: TV or radio program

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生命起源に関する報道
アミノ酸重合に成功

ニュートン

2011/05

Type: Newspaper, magazine
生命の起源

CNN

2010/05/30

Type: TV or radio program

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東北大の最前線
最新の科学

青葉理学振興会

2010/04/01

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アミノ酸生成に関する最新の記事
アミノ酸生成に成功

朝日新聞，読売新聞

2008/12/08

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月と地球

NHK

2008/10/13

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NHKスペシャル、月と地球（１０月１３日放送）に出演
日本学術振興会先端科学シンポジウム紹介

日本学術振興会

2008/01/10

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地球最古の生命

JAMSTEC

2007/10/01

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JAMSTECの一般向け広報誌に寄稿
不思議のとびら

東北放送

2006/05/13

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東北地方に伝わる不思議な現象を理学的に解明する企画。鳴子温泉の軽石の説明と実験でテレビ出演

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Other 18

カンブリア時代縞状鉄鉱層の窒素同位体測定

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カンブリア時代縞状鉄鉱層の窒素同位体測定
グリーンランドイスア地域に産す世界最古の生命の痕跡

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グリーンランドイスア地域に産す世界最古の生命の痕跡
アミノ酸を指標にした石油品質評価

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アミノ酸を指標にした石油品質評価
海底熱水鉱床の探査法

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海底熱水鉱床の探査法
地質試料に残されたDNA探査

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地質試料に残されたDNA探査
超高圧状態でのアミノ酸生成

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超高圧状態でのアミノ酸生成（共同研究協定締結）
無酸素温泉環境における初期微生物の研究

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d無酸素温泉環境における初期微生物の研究
無酸素温泉環境における初期微生物の研究

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無酸素温泉環境における初期微生物の研究
生命起源共同研究

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学際重点支援プログラムによる生命起源共同研究
アミノ酸から細胞分裂まで：東北大の強みを生かした生命起源研究の新展開

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東北大の強みを生かし、生命起源研究の新展開を拓く
黒鉱成因査から見る海底熱水鉱床探査

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秋田県の黒鉱鉱床の総合地質調査
水曜海山の軽元素挙動調査
南部マリアナ背弧拡大軸における新規火山活動
カナダオンタリオ州における初期生命体痕跡の探査
mass production of bio-essential organic molecules on the early earth

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隕石海洋衝突実験を物質材料研究機構で行い、生成物を東北大で分析する。
The oldest formation on the Earth in Greenland
新規硫酸還元菌の発見

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宮城県鳴子温泉で新規硫酸還元菌を見いだす研究。
Snow Ball Earth

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南アフリカに産する世界最古のスノーボールアース現象を記録した岩石の地球化学分析

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