Researcher basic information

• PhD (Science), Hokkaido University, Mar. 2023

• https://researchmap.jp/maikeda?lang=en

• https://orcid.org/0000-0002-7542-9464
• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=202201021184306059
• https://www.maikeda-lab.com/

• https://orcid.org/0000-0002-7542-9464

• 202201021184306059

• Fungi
• Palynomorph
• Molecular Paleontology
• Lichen
• Molecular fossil
• Organic Geochemistry

• Natural Science, Biogeosciences, Organic Geochemistry, Biogeochemistry

• Bachelor's degree program, School of Science
• Master's degree program, Graduate School of Science
• Doctoral (PhD) degree program, Graduate School of Science

Research activity information

• Aug. 2024, International Geoscience Programme 679, The Best Oral Presentation Award
  Vegetation response against environmental change during the Oceanic Anoxic Event 2 recorded by terrestrial plant biomarkers in sediments from the Tomamae (Hokkaido, Japan)
  International society
• 2021, Graduate School of Science, Hokkaido University, Outstanding Research Award
• 2020, The Japanese Association of Organic Geochemists, The Best Oral Presentation Award

• The Chicxulub impact signature in East Asia
  Hayu Ota; Junichiro Kuroda; Keiichi Hayashi; Hiroyuki Hoshi; Ken Sawada; Kohei Hosogaya; Hiroshi Nishi; Akira Ishikawa; Katsuhiko Suzuki; Masashi A. Ikeda; Yuji Orihashi; Mark Schmitz; Babu Ram Gyawali; Hironao Matsumoto; Reishi Takashima
  Communications Earth & Environment, 20 May 2026
  Scientific journal
• Steroids of lichen and their diagenetic derivatives: Experimental simulation of thermal alteration of lichen steroids
  Masashi A. Ikeda; Ken Sawada
  Researches in Organic Geochemistry, 41, 1, 1, 14, 31 Jul. 2025, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
  English, Scientific journal, 46077366;41954823
• GC-MS analysis of tricyclic and tetracyclic terpanes in Proterozoic and Paleozoic sedimentary rocks
  Risa Shigi; Masashi A. Ikeda; Takuto Ando; Reishi Takashima; Toshifumi Komatsu; Ken Sawada
  Researches in Organic Geochemistry, 40, 2, 25, 41, 26 Dec. 2024, [Peer-reviewed], [Domestic magazines]
  Japanese, Scientific journal
• Evaluation of fossil geomacromolecular sources by the pyrolysis of density fractions of kerogens from Cretaceous and Miocene organic-rich marine shales
  Gen Sakugawa; Masashi A. Ikeda; Takuto Ando; Reishi Takashima; Hiroshi Nishi; Ken Sawada
  GEOCHEMICAL JOURNAL, 58, 4, 138, 154, Geochemical Society of Japan, Jun. 2024, [Peer-reviewed], [Domestic magazines]
  English, Scientific journal
• Large igneous province activity drives oceanic anoxic event 2 environmental change across eastern Asia
  R. Takashima; D. Selby; T. Yamanaka; Y. Kuwahara; H. Nakamura; K. Sawada; M. A. Ikeda; T. Ando; K. Hayashi; M. Nishida; T. Usami; D. Kameyama; H. Nishi; A. Kuroyanagi; B. R. Gyawali
  Communications Earth & Environment, 5, 1, Springer Science and Business Media LLC, 19 Feb. 2024, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, Abstract
  
  During mid-Cretaceous Oceanic Anoxic Event 2, significant increase of atmospheric carbon dioxide concentrations from the eruption of the large igneous provinces is hypothesized to have induced a humid climate and an elevation in nutrient runoff from continents to the oceans, resulting in oxygen depletion in the ocean. However, hitherto there is limited insight into the driving factors of Oceanic Anoxic Event 2 from the Pacific and Asian continental margins, even though the former and the latter were the largest ocean and landmass at that time. Here, a multiproxy analysis for the Oceanic Anoxic Event 2 interval of the Yezo Group –deposited on northwestern Pacific along the active Asian continental margin– is interpretated to identify seven volcanic pulses, five of which may have elevated humidity, weathering intensity, and vegetational change in the eastern margin of Asia. Moreover, oxygen depletion occurred simultaneously in the northwest Pacific. Given that these environmental changes in the eastern margin of Asia were penecontemporaneous with the global carbon burial intervals during Oceanic Anoxic Event 2, the elevated nutrient supply from the Asian continental margin to the Pacific Ocean may have, in part, contributed to the worldwide depletion of oxygen of the ocean during Oceanic Anoxic Event 2.
• Aliphatic hydrocarbons in the lichen class Lecanoromycetes and their potential use as chemotaxonomic indicators and biomarkers
  Masashi A. Ikeda; Hideto Nakamura; Ken Sawada
  Organic Geochemistry, 179, 104588, Elsevier BV, May 2023, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Long-chain alkenes and alkadienes of eight lichen species collected in Japan
  Masashi A. Ikeda; Hideto Nakamura; Ken Sawada
  Phytochemistry, 189, 112823, Sep. 2021, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Aliphatic hydrocarbons identiAliphatic hydrocarbons identified in lichen genus Cladonia and Xanthoria : Potential for their chemotaxonomic and environmental indicators
  Masashi A. Ikeda; Hideto Nakamura; Ken Sawada
  Researches in Organic Geochemistry, 34, 2, 15, 28, The Japanese Association of Organic Geochemists, 30 Dec. 2018, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
  Japanese, Aliphatic hydrocarbons were analyzed in 3 species (Cladonia vulcani, Cladonia scabriuscula, and Xanthoria sp.) of lichens collected from Hokkaido and Hyogo Prefectures, Japan. Molecular composition of n-alkanes is likely influenced by precipitation, as the long chain n-alkanes are produced under arid environments. Alkenes such as heptadecene are also detected as major components in these samples. Molecular composition of these alkanes is different between the genus Xanthoria and Cladonia, suggesting that the composition is influenced by taxonomic diversity. Molecular composition of the aliphatic hydrocarbons other than n-alkanes and alkenes detected are far different between the genera Xanthoria and Cladonia, but are almost similar in these 2 species of the genus Cladonia, potentially depending on taxonomy at the genus level. From these results, we predict that the alkenes, as well as other aliphatic hydrocarbons, can be useful as a chemotaxonomic marker, while the composition of n-alkanes can be an environmental indicator.

• Steroids of lichen and their diagenetic derivatives
  Masashi A. Ikeda; Ken Sawada, The Japanese Association of Organic Geochemists. Dataset, 2025, [Lead author, Corresponding author]
  English, Others, 46077366;41954823
• Evaluation of fossil geomacromolecular sources by the pyrolysis of density fractions of kerogens from Cretaceous and Miocene organic-rich marine shales
  Sakugawa Gen; Ikeda Masashi A.; Ando Takuto; Takashima Reishi; Nishi Hiroshi; Sawada Ken; Sawada Ken, Geochemical Journal (Web), 58, 4, 2024
• Multi-proxy dataset of mid-Cretaceous Oceanic Anoxic Event 2 for the Omagari-zawa section, Hokkaido, Japan.
  Takashima, Reishi; Selby, David; Yamanaka, Toshiro; Kuwahara, Yoshihiro; Nakamura, Hideto; Sawada, Ken; Ikeda, Masashi A; Ando, Takuto; Hayashi, Keiichi; Nishida, Mari; Usami, Toshiaki; Kameyama, Daichi; Nishi, Hiroshi; Kuroyanagi, Azumi; Gyawali; Babu Ram, PANGAEA, 2024
  Others

• Diversification of marine ecosystems recorded by molecular fossils in the Mesoproterozoic sedimentary rocks of Greenland
  Risa Shigi; Masashi A. Ikeda; Takuto Ando; Ken Sawada
  Palaeontological Society of Japan Annual meeting 2026, 27 Jun. 2026, Palaeontological Society of Japan, Japanese, Oral presentation
  26 Jun. 2026 - 28 Jun. 2026, Osaka, Japan, [Domestic Conference]
• Reconstruction of paleovegetation changes using biomarkers in sedimentary rocks of the K/Pg boundary in the Nemuro Group, Hokkaido, Japan
  Ritomi Kinoshita; Masashi A. Ikeda; Ken Sawada; Keiichi Hayashi; Hayu Ota; Junichiro Kuroda; Hiroyuki Hoshi; Reishi Takashima; Hiroshi Nishi
  JpGU-AGU Joint Meeting 2026, 29 May 2026, JpGU, AGU, English, Poster presentation
  24 May 2026 - 29 May 2026, Chiba, Japan, [International presentation]
• Terrestrial and marine ecosystem responses to the Early Late Paleocene Event (ELPE) in the Nemuro Group, Hokkaido, Japan
  Tatsuya Yoshida; Keiichi Hayashi; Hideto Nakamura; Masashi A. Ikeda; Takuto Ando
  JpGU-AGU Joint Meeting 2026, 29 May 2026, JpGU, AGU, English, Oral presentation
  24 May 2026 - 29 May 2026, Chiba, Japan, [International presentation]
• Unraveling mid-Cretaceous terrestrial ecosystem dynamics through fungal microfossils
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Reishi Takashima; Hiroshi Nishi
  JpGU-AGU Joint Meeting 2026, 27 May 2026, JpGU, AGU, English, Poster presentation
  24 May 2026 - 29 May 2026, Chiba, Japan, [International presentation]
• Phycoma-like organic microfossils in the Mesoproterozoic sedimentary rocks from northwestern Greenland
  Risa Shigi; Masashi A. Ikeda; Takuto Ando; Ken Sawada
  JpGU-AGU Joint Meeting 2026, 27 May 2026, JpGU, AGU, English, Oral presentation
  24 May 2026 - 29 May 2026, Chiba, Japan, [International presentation]
• Diversification of primary producers revealed from molecular fossils in the Mesoproterozoic sedimentary rocks from northwestern Greenland
  Risa Shigi; Masashi A. Ikeda; Takuto Ando; Ken Sawada
  The 42th Symposium on Organic Geochemistry, 05 Nov. 2025, Japanese, Oral presentation
  04 Nov. 2025 - 05 Nov. 2025
• Reconstruction of terrestrial paleovegetation by biomarker analysis during the Turonian-Campanian in the Haborogawa Formation, Yezo Group, Hokkaido
  Atsushi TAKAHASHI; Hideto NAKAMURA; Masashi A. IKEDA; Takuto ANDO; Ken SAWADA; Reishi TAKASHIMA; Hiroshi NISHI
  The 42th Symposium on Organic Geochemistry, 05 Nov. 2025, Japanese, Oral presentation
  04 Nov. 2025 - 05 Nov. 2025
• Investigation of biomarkers by thermal maturation experiments: Insights into the origin of dibenzofurans in sedimentary rocks
  Masashi A. Ikeda; Kenta Asahina; Ken Sawada
  The 42th Symposium on Organic Geochemistry, 05 Nov. 2025, Japanese, Poster presentation
  04 Nov. 2025 - 05 Nov. 2025
• Organic geochemical analysis of Nemuro Group: Paleoenvironmental reconstruction in the Early Paleogene
  Tatsuya YOSHIDA; Hideto NAKAMURA; Keiichi HAYASHI; Masashi A. IKEDA; Takuto ANDO
  The 42th Symposium on Organic Geochemistry, 04 Nov. 2025, Japanese, Oral presentation
  04 Nov. 2025 - 05 Nov. 2025
• Comparison of molecular fossil records in sediments deposited around the K/Pg boundary between the Kawaruppu and the Mokawaruppu river sections in Hokkaido, Japan
  Ritomi Kinoshita; Masashi A. Ikeda; Ken Sawada; Keiichi Hayashi; Hayu Ota; Junichiro Kuroda; Hiroyuki Hoshi; Reishi Takashima; Hiroshi Nishi
  The 42th Symposium on Organic Geochemistry, 04 Nov. 2025, Japanese, Oral presentation
  04 Nov. 2025 - 05 Nov. 2025
• Reconstruction of depositional environment by biomarker analysis during the Coniacian-Santonian in the Haborogawa Formation, Yezo Group, Hokkaido
  Atsushi TAKAHASHI; Hideto Nakamura; Masashi A. Ikeda; Takuto Ando; Ken Sawada; Reishi Takashima; Hiroshi Nishi
  The 132nd Annual Meeting of the Geological Society of Japan, 16 Sep. 2025, Geological Society of Japan, Japanese, Oral presentation
  14 Sep. 2025 - 16 Sep. 2025, Kumamoto, Japan, [Domestic Conference]
• Terrestrial and marine paleoecology of the Middle Paleocene: Insights from biomarker analysis of the Nemuro Group
  Tatsuya Yoshida; Hideto Nakamura; Keiichi Hayashi; Masashi Ikeda; Takuto Ando
  The 132nd Annual Meeting of the Geological Society of Japan, 15 Sep. 2025, Geological Society of Japan, Japanese, Oral presentation
  14 Sep. 2025 - 16 Sep. 2025, Kumamoto, Japan, [Domestic Conference]
• C40:2Et alkenone, a biomarker of Cretaceous haptophytes: paleothermometric importance of its cis stereoisomer
  Takashi Hasegawa; Tsukika Takahashi; Masashi A. Ikeda; Hiromichi Komiya
  12th International Cretaceous Symposium, 02 Sep. 2025, English, Poster presentation
  31 Aug. 2025 - 05 Sep. 2025, Hanover, Germany, [International presentation]
• Terrestrial ecosystem response against environmental change across the Cenomanian/Turonian boundary recorded by biomarkers in sediments from the Great Valley Sequence, California, USA
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Reishi Takashima; Hiroshi Nishi
  12th International Cretaceous Symposium, 01 Sep. 2025, English, Oral presentation
  31 Aug. 2025 - 05 Sep. 2025, Hanover, Germany, 46077366, [International presentation]
• Implication for diatom molecular fossil records around the K/Pg boundary in the Kawaruppu, Hokkaido, Japan
  Ritomi Kinoshita; Masashi A. Ikeda; Ken Sawada; Keiichi Hayashi; Hayu Ota; Junichiro Kuroda; Hiroyuki Hoshi; Reishi Takashima; Hiroshi Nishi
  Palaeontological Society of Japan Annual meeting 2025 (Sapporo), 29 Jun. 2025, Palaeontological Society of Japan, Japanese, Oral presentation
  27 Jun. 2025 - 29 Jun. 2025, Sapporo, Hokkaido, Japan, [Domestic Conference]
• Diversity of organic microfossils in the Mesoproterozoic sedimentary rocks from northwestern Greenland
  Risa Shigi; Masashi A. Ikeda; Takuto Ando; Ken Sawada
  Palaeontological Society of Japan Annual meeting 2025 (Sapporo), 28 Jun. 2025, Palaeontological Society of Japan, Japanese, Oral presentation
  27 Jun. 2025 - 29 Jun. 2025, Sapporo, Hokkaido, Japan, [Domestic Conference]
• Reconstruction of fungal flora changes during the Mid-Cretaceous: Application of fungal palynomorph analysis in the sediments deposited during the Cretaceous Oceanic Anoxic Events
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Reishi Takashima; Hiroshi Nishi
  Palaeontological Society of Japan Annual meeting 2025 (Sapporo), 28 Jun. 2025, Palaeontological Society of Japan, Japanese, Poster presentation
  27 Jun. 2025 - 29 Jun. 2025, Sapporo, Hokkaido, Japan, [Domestic Conference]
• Variety of Cretaceous alkenones as product of haptophytes: perspective for understanding high latitude paleotemperature during Cretaceous
  Takashi Hasegawa; Yukiko Kozaka; Tsukika Takahashi; Masashi A. Ikeda; Hiromichi Komiya
  Japan Geoscience Union Meeting 2025, 30 May 2025, Japan Geoscience Union, Japanese, Oral presentation
  25 May 2025 - 30 May 2025, MAKUHARI MESSE, Chiba, Japan, [Domestic Conference]
• Paleoenvironmental variations recorded by molecular fossils in sedimentary rocks deposited across the Cretaceous/Paleogene boundary in the Nemuro Group, Hokkaido, Japan
  Ritomi Kinoshita; Masashi A. Ikeda; Ken Sawada; Keiichi Hayashi; Hayu Ota, Junichiro; Kuroda; Hiroyuki Hoshi; Reishi Takashima; Hiroshi Nishi
  Japan Geoscience Union Meeting 2025, 28 May 2025, Japan Geoscience Union, Oral presentation
  25 May 2025 - 30 May 2025, MAKUHARI MESSE, Chiba, Japan, [Domestic Conference]
• Tricyclic terpanes in the sedimentary rocks from Greenland (the Mesoproterozoic) and Vietnam (the Devonian-Carboniferous boundary)
  Risa Shigi; Masashi A. Ikeda; Takuto Ando; Reishi Takashima; Toshifumi Komatsu; Ken Sawada
  The 41th Symposium on Organic Geochemistry, Matsue 2024, 26 Sep. 2024, Japanese, Oral presentation
  26 Sep. 2024 - 27 Sep. 2024
• Terrestrial paleovegetation changes reconstructed by biomarkers and Rock-Eval analysis across the Cenomanian/Turonian boundary in California, North America
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Reishi Takashima; Hiroshi Nishi
  The 41th Symposium on Organic Geochemistry, Matsue 2024, 26 Sep. 2024, Japanese, Poster presentation
  26 Sep. 2024 - 27 Sep. 2024
• Integrated stratigraphy and radiometric ages across the K-Pg boundary in Shiranuka Hill, Hokkaido, Japan
  Reishi Takashima; Hayu Ota; Junichiro Kuroda; Mark Schmitz; Keiichi Hayashi; Hiroshi Nishi; Yuji Orihashi; Hiroyuki Hoshi; Ken Sawada; Toshiro Yamanaka; Masashi A. Ikeda; Kohei Hosogaya
  The 131st Annual Meeting(2024yamagata), 10 Sep. 2024, Japanese, Oral presentation
  08 Sep. 2024 - 10 Sep. 2024
• Thermal maturity and taxonomic insights from palynomorph coloration: Preliminary results for the immature sediments of the Cretaceous, Yezo Group
  Maho Hayakawa; Hideto Nakamura; Masashi A. Ikeda; Ken Sawada; Reishi Takashima; Hiroshi Nishi
  the 37th International Geological Congress 2024, 28 Aug. 2024, International Union of Geological Sciences, English, Poster presentation
  25 Aug. 2024 - 31 Aug. 2024, Busan, Korea, Republic of, [International presentation]
• Vegetation response against environmental change during the Oceanic Anoxic Event 2 recorded by terrestrial plant biomarkers in sediments from the Tomamae (Hokkaido, Japan)
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Hideto Nakamura; Reishi Takashima; Hiroshi Nishi
  the 37th International Geological Congress 2024, 28 Aug. 2024, International Union of Geological Sciences, English, Oral presentation
  25 Aug. 2024 - 31 Aug. 2024, Busan, Korea, Republic of, [International presentation]
• Thermal maturation experiments of lichen materials: Origin and diagenetic alternation of aromatic furans in sedimentary rocks
  Masashi A. Ikeda; Kenta Asahina; Ken Sawada
  Japan Geoscience Union Meeting 2024, 30 May 2024, Japan Geoscience Union, Oral presentation
  26 May 2024 - 31 May 2024, Chiba, Japan, [Domestic Conference]
• Paleoecological reconstruction by molecular fossil analysis of the Mesoproterozoic sedimentary rocks from northwestern Greenland
  Risa Shigi; Masashi A. Ikeda; Takuto Ando; Ken Sawada
  Japan Geoscience Union Meeting 2024, 29 May 2024, Japan Geoscience Union, Poster presentation
  26 May 2024 - 31 May 2024, Chiba, Japan, [Domestic Conference]
• Osmium isotopic records and abundances of platinum group elements of the Cretaceous-Paleogene boundary in the Nemuro Group
  Hayu Ota; Junichiro Kuroda; Reishi Takashima; Hiroyuki Hoshi; Ken Sawada; Masashi A. Ikeda; Keiichi Hayashi; Hiroshi Nishi; Akira Ishikawa
  Japan Geoscience Union Meeting 2024, 28 May 2024, Japan Geoscience Union, Oral presentation
  26 May 2024 - 31 May 2024, Chiba, Japan, [Domestic Conference]
• Variation of fungus flora under super greenhouse environment during the Cretaceous Oceanic Anoxic Events
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Hideto Nakamura; Reishi Takashima; Hiroshi Nishi
  Paleosciences Society 9th annual meeting, 04 Dec. 2023, Paleosciences Society, Japanese, Oral presentation
  03 Dec. 2023 - 04 Dec. 2023, Kanazawa, Ishikawa, Japan, [Domestic Conference]
• Paleoenvironmental reconstruction by biomarker analyses of sedimentary rocks deposited across the Cretaceous/Paleogene boundary in the Nemuro Group, Hokkaido, Japan
  Kazuo Hayashi; Masashi A Ikeda; Ken Sawada; Keiichi Hayashi; Reishi Takashima; Hiroshi Nishi; Junichiro Kuroda; Hayu Ota
  The 130th Annual Meeting of the Geological Society of Japan (2023Kyoto), 18 Sep. 2023, The Geological Society of Japan, Japanese, Oral presentation
  17 Sep. 2023 - 19 Sep. 2023, Kyoto, Japan, [Domestic Conference]
• Exploring paleobiological and geological insights through color analysis of pollen and spore fossils in sedimentary rocks of the Haborogawa Formation, Yezo Group, Hokkaido
  Maho Hayakawa; Hideto Nakamura; Masashi A Ikeda; Ken Sawada; Reishi Takashima; Hiroshi Nishi
  The 130th Annual Meeting of the Geological Society of Japan (2023Kyoto), 18 Sep. 2023, The Geological Society of Japan, Japanese, Oral presentation
  17 Sep. 2023 - 19 Sep. 2023, Kyoto, Japan, [Domestic Conference]
• Reconstruction and comparison of paleovegetation changes by biomarker analysis during the Cretaceous Oceanic Anoxic Events in the Tomamae area, Hokkaido and California, North America
  Masashi A Ikeda; Ken Sawada; Takuto Ando; Hideto Nakamura; Reishi Takashima; Hiroshi Nishi
  The 130th Annual Meeting of the Geological Society of Japan (2023Kyoto), 18 Sep. 2023, The Geological Society of Japan, Japanese, Oral presentation
  17 Sep. 2023 - 19 Sep. 2023, Kyoto, Japan, [Domestic Conference]
• Investigation of fossilization processes of tree fossils by pyrolysis and thermochemolysis
  Ken Sawada; Jinya Nakamura; Masashi A. Ikeda; Hideto Nakamura; Minoru Tsukagoshi
  Water-Rock Interaction WRI-17/ Applied Isotope Geochemistry AIG-14, 18 Aug. 2023, WRI-17 Organizing Committee, English, Oral presentation
  18 Aug. 2023 - 22 Aug. 2023, Sendai, Japan, [International presentation]
• Variations in terpenoid composition in Japanese amber extracts: diagenesis and chemotaxonomy
  Hideto Nakamura; Aya Kubota; Yasuhiro Iba; Hiroki Yano; Masashi A. Ikeda; Takuto Ando
  Water-Rock Interaction WRI-17/ Applied Isotope Geochemistry AIG-14, 18 Aug. 2023, WRI-17 Organizing Committee, English, Oral presentation
  18 Aug. 2023 - 22 Aug. 2023, Sendai, Japan, [International presentation]
• Diagenetic alteration of aromatic furans during early stage of thermal maturation: examination for lichen biomarkers in ancient sediment
  Masashi A Ikeda; Ken Sawada
  Water-Rock Interaction WRI-17/ Applied Isotope Geochemistry AIG-14, 18 Aug. 2023, WRI-17 Organizing Committee, English, Oral presentation
  18 Aug. 2023 - 22 Aug. 2023, Sendai, Japan, [International presentation]
• Reconstruction of the Kuroshio states based on microfossil assemblages from SCORE Expedition 913 Site C9037 off Shikoku, Japan
  Daisuke Kuwano; Minoru Ikehara; Kenji M. Matsuzaki; Ayumi Maeda; Takuya Sagawa; Keiji Horikawa; Yoshimi Kubota; Yuki Morono; Natsumi Okutsu; Chikyu SCORE Exp. 913 Science Party
  2nd Asian Palaeontological Congress, 07 Aug. 2023, English, Poster presentation
  04 Aug. 2023 - 07 Aug. 2023, Tokyo, Japan, [International presentation]
• Climate, vegetation and oceanographic change in the eastern margin of Asia during Oceanic Anoxic Event 2 driven by pulsed Large Igneous Province activity
  Reishi Takashima; David Selby; Toshiro Yamanaka; Yoshihiro Kuwahara; Hideto Nakamura; Ken Sawada; Masashi A. Ikeda; Takuto Ando; Keiichi Hayashi; Hiroshi Nishi; Azumi Kuroyanagi; Babu Ram Gyawali
  2nd Asian Palaeontological Congress, 07 Aug. 2023, English, Poster presentation
  04 Aug. 2023 - 07 Aug. 2023, Tokyo, Japan, [International presentation]
• Terrestrial and marine molecular fossil fingerprints of the Yezo Group record the Late Cretaceous paleoenvironmental evolution in the NW Pacific Margin
  Hideto Nakamura; Takuto Ando; Masashi A. Ikeda; Ken Sawada; Reishi; Takashima; Hiroshi Nishi
  2nd Asian Palaeontological Congress, 05 Aug. 2023, English, Oral presentation
  04 Aug. 2023 - 07 Aug. 2023, Tokyo, Japan, [International presentation]
• Turonian to Santonian paleovegetation changes reconstructed from palynological records of the Haborogawa Formation, Yezo Group, Hokkaido, Japan
  Maho Hayakawa; Masashi A. Ikeda; Hideto Nakamura; Ken Sawada; Reishi Takashima; Hiroshi Nishi
  2nd Asian Palaeontological Congress, 05 Aug. 2023, English, Oral presentation
  04 Aug. 2023 - 07 Aug. 2023, Tokyo, Japan, [International presentation]
• Variation of vegetation and carbon isotope ratio recorded in sediments from the Tomamae area, Hokkaido and California, North America
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Hideto Nakamura; Reishi Takashima; Hiroshi Nishi
  日本地質学会北海道支部2023年度例会(個人講演会), 17 Jun. 2023, The Geological Society of Japan, Japanese, Public discourse
  17 Jun. 2023 - 17 Jun. 2023, Sapporo, Japan
• Aromatic furans in sedimentary rocks and their origin
  Masashi A. Ikeda; Takuto Ando; Ken Sawada
  Japan Geoscience Union Meeting 2023, 26 May 2023, Japan Geoscience Union, English, Oral presentation
  21 May 2023 - 26 May 2023, Chiba, Japan
• Integrated stratigraphy across the Cretaceous/Paleocene boundary in the Shiranuka Hill, Hokkaido, Japan
  Reishi Takashima; Keiichi Hayashi; Junichiro Kuroda; Hayu Ota; Hiroyuki Hoshi; Yuji Orihashi; Hiroshi Nishi; Toshiro Yamanaka; Ken Sawada; Kazuo Hayashi; Masashi A. Ikeda; Kohei Hosogaya; Yoshihiro Asahara
  Japan Geoscience Union Meeting 2023, 26 May 2023, Japan Geoscience Union, Japanese, Oral presentation
  21 May 2023 - 26 May 2023, Chiba, Japan
• Paleoenvironmental reconstruction by biomarker analyses of sedimentary rocks deposited across the Cretaceous/Paleogene boundary in the Nemuro Group, Hokkaido, Japan
  Kazuo Hayashi; Masashi A. Ikeda; Ken Sawada; Keiichi Hayashi; Reishi Takashima; Hiroshi Nishi
  第39回有機地球化学シンポジウム（2022年 横須賀シンポジウム）, 15 Dec. 2022, The Japanese Association of Organic Geochemists, Japanese, Oral presentation
  15 Dec. 2022 - 15 Dec. 2022, Online, [Domestic Conference]
• Reconstruction of paleoenvironmental variations and terrestrial organic matter transport by biomarker analysis of a C9037 core from the northwestern Pacific off southwestern Japan: Preliminary reports
  Masashi A. Ikeda; Hiroyasu Asahi; Ken Sawada
  Western Pacific Drilling Meeting 2022, 12 Oct. 2022, English, Public symposium
  12 Oct. 2022 - 14 Oct. 2022, Nankoku-city, Kochi, Japan
• Reconstruction of the Late Cretaceous paleovegetation based on palynological analysis in the Haborogawa Formation of the Yezo Group, Tomamae Area, Hokkaido, Japan
  Maho Hayakawa; Masashi A. Ikeda; Ken Sawada; Reishi Takashima; Hiroshi Nishi; Hideto Nakamura
  The 37th Annual Meeting of the Japanese Association of Historical Botany & The 63th Annual Meeting of the PALYNOLOGICAL SOCIETY OF JAPAN, 02 Oct. 2022, The Japanese Association of Historical Botany/ The Palynological Society of Japan, Japanese, Oral presentation
  01 Oct. 2022 - 02 Oct. 2022, Nara, Japan, [Domestic Conference]
• Reconstruction of fungal flora changes by fungal palynomorph analysis in the sediments deposited during the Cretaceous Oceanic Anoxic Events
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Reishi Takashima; Hiroshi Nishi
  The 129th Annual Meeting of the Geological Society of Japan (2022Waseda), 04 Sep. 2022, The Geological Society of Japan, Japanese, Oral presentation
  04 Sep. 2022 - 11 Sep. 2022, Waseda, Tokyo, Japan, [Domestic Conference]
• Reconstruction of Late Cretaceous paleovegetation based on terrestrial palynomorphs and biomarker analysis of the forearc basin sediments from the Haborogawa Formation, Yezo Group, Hokkaido, Japan
  Maho Hayakawa; Masashi A. Ikeda; Ken Sawada; Reishi Takashima; Hiroshi Nishi; Hideto Nakamura
  Japan Geoscience Union Meeting 2022, 25 May 2022, Japan Geoscience Union, English, Oral presentation
  22 May 2022 - 27 May 2022, Chiba, Japan, [Domestic Conference]
• Oxygen-containing aromatic compounds detected in the Mesoproterozoic sedimentary rocks, Northwest Greenland: The origins and significance for earth’s history
  Masashi A. Ikeda; Yuki Hara; Takuto Ando; Ken Sawada
  Japan Geoscience Union Meeting 2022, 22 May 2022, Japan Geoscience Union, Japanese, Oral presentation
  22 May 2022 - 27 May 2022, Chiba, Japan, [Domestic Conference]
• Fungal and lichen biomarker analysis of the sediments deposited across the Cenomanian/Turonian boundary: Reconstruction of fungal flora changes
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Hideto Nakamura; Reishi Takashima; Hiroshi Nishi
  第38回 有機地球化学会 （2021年札幌シンポジウム）, 29 Nov. 2021, The Japanese Association of Organic Geochemists, Japanese, Oral presentation
  29 Nov. 2021 - 30 Nov. 2021, Sapporo, Japan, [Domestic Conference]
• Palynological analysis of the Upper Cretaceous Yezo Group, Kotanbetsu area, Tomamae city, Hokkaido
  Maho Hayakawa; Masashi A. Ikeda; Ken Sawada; Reishi Takashima; Hiroshi Nishi
  日本地質学会 北海道支部令和3年度 例会, 10 Jul. 2021, Japanese, Public discourse
  10 Jul. 2021 - 10 Jul. 2021, Online, Japan
• Reconstruction of paleovegetation changes by pollen, palynomorph, and kerogen analyses of the Late Cretaceous sediments from the Kotanbetsu area, Hokkaido, Japan
  Maho Hayakawa; Ken Sawada; Masashi A. Ikeda; Reishi Takashima; Hiroshi Nishi
  Japan Geoscience Union Meeting 2021, 06 Jun. 2021, Japan Geoscience Union, Japanese, Oral presentation
  30 May 2021 - 06 Jun. 2021, Online, [Domestic Conference]
• Paleovegetation changes reconstructed by terrestrial plant biomarker analyses in the sediments deposited across the Cenomanian/Turonian boundary in the Great Valley Sequence, northern California, USA
  Masashi A. Ikeda; Ken Sawada; Reishi Takashima; Hiroshi Nishi
  Japan Geoscience Union Meeting 2021, 04 Jun. 2021, Japan Geoscience Union, Japanese, Oral presentation
  30 May 2021 - 06 Jun. 2021, Online, [Domestic Conference]
• Reconstruction of palaeovegetation by pollen, palynomorph and biomarker analyses in the Cretaceous sedimentary rocks from Hokkaido, Japan
  Maho Hayakawa; Masashi Ikeda; Ken Sawada; Reishi Takashima; Hiroshi Nishi
  有機地球化学「若手・学生オンライン研究発表会2020」, 05 Dec. 2020, The Japanese Association of Organic Geochemists, Japanese, Oral presentation
  05 Dec. 2020 - 05 Dec. 2020, Online, [Domestic Conference]
• Lipid analysis of biological lichen samples: Potential for molecular fossils
  Masashi A. Ikeda; Ken Sawada; Hideto Nakamura
  有機地球化学「若手・学生オンライン研究発表会2020」, 05 Dec. 2020, The Japanese Association of Organic Geochemists, Japanese, Oral presentation
  05 Dec. 2020 - 05 Dec. 2020, Online, [Domestic Conference]
• Paleoecological variations reconstructed by organic matter derived from lichens and fungi across the Cenomanian/Turonian boundary in the Tomamae area, northern Hokkaido, Japan
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Hideto Nakamura; Reishi Takashima; Hiroshi Nishi
  JpGU - AGU Joint Meeting 2020, May 2020, Japan Geoscience Union (JpGU) / American Geophysical Union (AGU), English, Poster presentation
  24 May 2020 - 28 May 2020, Chiba, Japan, [International presentation]
• Fungal palynomorph analysis in the sediments deposited during the mid-Cretaceous Oceanic Anoxic Events
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Reishi Takashima
  The 126th Annual Meeting of the Geological Society of Japan (2019Yamaguchi), 25 Sep. 2019, The Geological Society of Japan, Japanese, Oral presentation
  23 Sep. 2019 - 25 Sep. 2019, Yamaguchi, Japan, [Domestic Conference]
• Blackening of Pliocene tree fossils from the Yasu River, Shiga Prefecture, Japan.
  Nakamura Jinya; Sawada Ken; Ikeda Masashi A; Nakamura Hideto; Tsukagoshi Minoru
  The 126th Annual Meeting of the Geological Society of Japan (2019Yamaguchi), 24 Sep. 2019, The Geological Society of Japan, Japanese, Oral presentation
  23 Sep. 2019 - 25 Sep. 2019, Yamaguchi, Japan, [Domestic Conference]
• Hydrocarbon analysis of biological lichen samples: Potential for chemotaxonomic and environmental indicators
  Masashi A. Ikeda; Ken Sawada; Hideto Nakamura
  第37回有機地球化学シンポジウム (2019年金沢シンポジウム), 29 Aug. 2019, The Japanese Association of Organic Geochemists, Japanese, Poster presentation
  28 Aug. 2019 - 29 Aug. 2019, Ishikawa, Japan, [Domestic Conference]
• Investigation of fossilization processes of tree fossils by thermochemolysis and biomarker analysis
  Jinya Nakamura; Ken Sawada; Masashi A. Ikeda; Hideto Nakamura; Minoru Tsukagoshi
  第37回有機地球化学シンポジウム (2019年金沢シンポジウム), 28 Aug. 2019, The Japanese Association of Organic Geochemists, Japanese, Oral presentation
  28 Aug. 2019 - 29 Aug. 2019, Ishikawa, Japan, [Domestic Conference]
• Variations in vegetation recorded by plant biomarkers in the sediments deposited across the Cenomanian/Turonian boundary in the Yezo Group, Tomamae area, Hokkaido: Potential for biomarker stratigraphy?
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Hideto Nakamura; Reishi Takashima; Hiroshi Nishi
  日本地質学会 北海道支部令和元年度 例会, 15 Jun. 2019, Japanese
  15 Jun. 2019 - 15 Jun. 2019
• Fossilization processes of Pliocene tree fossils from the Yasu River, Shiga Prefecture, Japan: Organic geochemical approach
  Jinya Nakamura; Ken Sawada; Masashi A. Ikeda; Hideto Nakamura; Minoru Tsukagoshi
  Japan Geoscience Union Meeting 2019, 30 May 2019, Japan Geoscience Union, Oral presentation
  26 May 2019 - 30 May 2019, Chiba, Japan, [Domestic Conference]
• Paleovegetation changes reconstructed by terrestrial plant biomarker analyses in the sediments deposited across the Cenomanian/Turonian boundary in the Tomamae area, Hokkaido, Japan
  Masashi A. Ikeda; Ken Sawada; Takuto Ando; Hideto Nakamura; Reishi Takashima; HIroshi Nishi
  Japan Geoscience Union Meeting 2019, 29 May 2019, Japan Geoscience Union, Japanese, Oral presentation
  26 May 2019 - 30 May 2019, Chiba, Japan, [Domestic Conference]
• Terrestrial environmental changes reconstructed by non-vascular plant biomarkers across the Cenomanian/Turonian boundary in the Tomamae area, northern Hokkaido, Japan
  Masashi Ikeda; Ken Sawada; Takuto Ando; Hideto Nakamura; Reishi Takashima; Hiroshi Nishi
  AGU Fall Meeting 2018, 14 Dec. 2018, American Geophysical Union, English, Poster presentation
  10 Dec. 2018 - 14 Dec. 2018, Washington,D.C., United States, [International presentation]
• Paleoenvironmental and paleoecological variations recorded by lichen biomarkers in the sediments deposited across the Cenomanian-Turonian boundary in the Tomamae area, northern Hokkaido, Japan
  Ikeda Masashi; Sawada Ken; Ando Takuto; Nakamura Hideto; Takashima Reishi; Nishi Hiroshi
  Annual Meeting of the Geological Society of Japan, 05 Sep. 2018, The Geological Society of Japan, Japanese, Oral presentation
  05 Sep. 2018 - 07 Sep. 2018, Sapporo & Tsukuba, [Domestic Conference]
• Paleoenvironmental and paleoecological variations recorded by lichen biomarkers in the sediments deposited across the Cenomanian-Turonian boundary in the Tomamae area, northern Hokkaido, Japan
  Masashi Ikeda; Ken Sawada; Takuto Ando; Hideto Nakamura; Reishi Takashima; Hiroshi Nishi
  Japan Geoscience Union Meeting 2018, 20 May 2018, Japan Geoscience Union, Japanese, Oral presentation
  20 May 2018 - 24 May 2018, Chiba, Japan, [Domestic Conference]

• Palaeontological Society of Japan
• The Geochemical Society of Japan
• Paleosciences Society
• American Geophysical Union
• Japan Geoscience Union
• The Japanese Association of Organic Geochemists
• The Geological Society of Japan

• 極端な温暖化イベントに対する陸域環境と植生の応答：モンゴルの奇跡の年縞から探る
  科学研究費助成事業
  Sep. 2025 - Mar. 2027
  Takashi Hasegawa; Keitaro Yamada; Yukiko Kozaka; Masashi Ikeda
  採択後約半年間しか経ていないため，本研究に直接関連する「実績」としてはまだ得られていない．研究計画にあるモンゴルのシネフダク層の掘削コアに関しては，その炭素同位体比測定および窒素同位体比測定を約1メートルの層位間隔進め，先行研究で得られている成果と調和的な結果を得た（OAE1aに相当すると考えられる-28‰程度の炭素同位体比値）．また，国際対比に関する重要な成果も出ている．シネフダク層の下部，OAE1aの炭素同位体比が大きく負に偏る（エクスカーション）層準直下で古地磁気の逆転層準を発見した．これは炭素同位体比と並んで重要な対比層準となる古地磁気クロンM0に相当すると判断できる．
  海洋無酸素事変(OAE)1aに関連する研究は，対比対象として日本の手取層群（陸成層に海成層が挟まる層序を持つ）に対しても進めている．こちらでも炭素同位体比層序を構築し，OAE1a直上の正のエクスカーションに相当する層準を突き止めることができた．またオーストラリア沖の国際深海化学掘削計画IODP試料(U1513)のOAE1a層準に関する炭素同位体比の調査も進め，こちらでは負のエクスカーションを検出している．このように，大陸内部－海陸境界部ー海という３つの環境に関してOAE1aに関してそれぞれ少しずつではあるが成果は出ており，2025年の白亜系国際シンポジウムで報告予定である．
  日本学術振興会, Fund for the Promotion of Joint International Research (International Collaborative Research), Kanazawa University, Coinvestigator, 24KK0194
• Elucidation of the evolutionary history of fungi during the Cretaceous Terrestrial Revolution
  科学研究費助成事業
  Apr. 2024 - Mar. 2027
  池田 雅志
  日本学術振興会, 特別研究員奨励費, 金沢大学, Principal investigator, 24KJ0094
• Organic geochemical study on the life history of lichen: Search for the molecular fossils and the reconstruction of fungal flora evolution
  Grants-in-Aid for Scientific Research
  Apr. 2022 - Mar. 2024
  Masashi Ikeda
  Japan Society for the Promotion of Science, Grant-in-Aid for JSPS Fellows, Hokkaido University, Principal investigator, 22KJ0098