2018 Fiscal Year Final Research Report
Global environmental changes triggered by Late Triassic impact event(Fostering Joint International Research)
| Project/Area Number |
16KK0104
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| Research Category |
Fund for the Promotion of Joint International Research (Fostering Joint International Research)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Geology
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| Research Institution | Kumamoto University |
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Principal Investigator |
Onoue Tetsuji 熊本大学, 大学院先端科学研究部(理), 准教授 (60404472)
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| Research Collaborator |
Rigo Manuel パドヴァ大学, 地球科学科, 准教授
Ebihara Mitsuru 首都大学東京, 大学院理工学研究科, 教授
Sato Honami 千葉工業大学, 次世代海洋資源研究センター, 上席研究員
Yamashita Katsuyuki 岡山大学, 大学院自然科学研究科, 准教授
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| Project Period (FY) |
2016 – 2018
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| Keywords | 地質学 / 地球化学 / 層位・古生物学 |
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| Outline of Final Research Achievements |
In order to assess environmental changes that were triggered by a large impact event in the middle-late Norian (Late Triassic), this study investigated conodont biostratigraphy and stratigraphic variations in strontium (Sr) and organic carbon isotope values from the Upper Triassic limestone successions in Italy and Austria. A significant biotic turnover in conodonts occurred in the late Norian, and values of the oxygen composition of conodonts suggest that this turnover process could be related to seawater temperature variation. At the same time, the Sr isotope ratios display a sudden negative excursion toward lower values and show a relatively quick recovery to pre-excursion Sr isotope ratios. Stratigraphic variation in organic carbon isotopic values from the study sections suggest marine primary productivity declined during this faunal turnover interval. These environmental changes could be related with the Norian impact event.
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| Free Research Field |
層序学
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| Academic Significance and Societal Importance of the Research Achievements |
従来の研究では，白亜紀／古第三紀境界だけが天体衝突が生物に及ぼす影響を評価できる唯一の研究対象であると考えられてきた．本研究では，応募者が発見した三畳紀後期の巨大隕石の衝突が，当時の生物や海洋環境にどのような影響を与えたかについて，ヨーロッパの上部三畳系石灰岩を対象とした野外調査および地球化学的検討（基礎生産，海水温など）に基づいて評価した．本研究の成果を基礎として，将来的には衝突した隕石の種類や大きさによって，どの程度の環境変動を引き起こし，絶滅などの地質イベントにつながったかについて定量的に議論できるようになると期待される．
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