著者
齊藤 諒介 海保 邦夫 高橋 聡
出版者
山口大学
雑誌
基盤研究(B)
巻号頁・発行日
2022-04-01

本研究では、大量絶滅時の気候変動を決めるメカニズムと陸海環境応答の解明を目的として、堆積有機分子、水銀分析、1次生産性に係るリンや鉄などの微量元素分析を行う。堆積有機分子の中でもコロネンは、通常の森林火災よりも高温で生成する芳香族炭化水素で、有機物から大規模火山噴火と小惑星衝突により多く生成される。オルドビス紀末大量絶滅についてコロネンの分布を確かめ、大量絶滅の大元の原因を確定する。さらに、寒冷化と同時の大量絶滅と温暖化と同時の大量絶滅を記録した地層中のコロネン含有比からマグマによる加熱温度を推定して気候制御ガス発生比率を推定し、それから気候変動を推定して表面海水温変化値との整合性を検証する。
著者
齊藤 諒介
出版者
日本有機地球化学会
雑誌
Researches in Organic Geochemistry (ISSN:13449915)
巻号頁・発行日
vol.32, no.2, pp.19-53, 2016

<p>The mass extinction at the end of Permian was the severest crisis in the Earth's history. Oceanic euxinia and acidification as well as global warming all have been hypothesized as causes for the mass extinction. However, oceanic euxinia occurred much earlier than the mass extinction, and oceanic acidification and global warming postdated. Accordingly, the cause for the end-Permian mass extinction is not fully understood. Organic geochemical studies have been the most extensively performed for the mass extinction event, and revealed important findings such as soil erosion, photic zone euxinia, and proliferation of cyanobacteria for the event. Recovery from the mass extinction was much delayed and took place in the Middle Triassic, after 5 million years from the mass extinction. Subsequently, the Early Triassic period is the transition interval from the mass extinction to the recovery. The environments in the Early Triassic were rather instable, and another mass extinctions and recoveries repeatedly occurred. Organic geochemical studies have suggested photic zone euxinia, stressful environments, and an occurrence of a previously undiscovered type of microbialite during the Early Triassic. In the present paper, I introduce the evidences of environmental and biotic changes through the end-Permian mass extinction to the Early Triassic.</p>