大量のマグマエピソードによって引き起こされた白期の海洋無酸素イベント2です
Steven C Turgeon1, Robert A Creaser
1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T2G 2E3, Canada. turgeonsc@ualberta.ca
Nature
|July 18, 2008
まとめ
海洋無酸素現象 (OAEs) は,海洋無酸素と有機炭素埋葬に関連しています. 新しい研究は,OAE2に先行したマグマ脈がOAE2に先行したことを示しており,それは白亜紀中期に広範な炭素結合を誘発したことを示唆しています.
科学分野:
- 地質化学 地質化学
- パレオセアノグラフィー
- 堆積物学 堆積物学 堆積物学 堆積物学 堆積物学
背景:
- 海洋無酸素現象 (OAEs) は,広範な海洋無酸素と有機炭素埋葬を含む.
- OAE2は,セノマニアン/トゥロニアン境界に位置し,白亜紀中期の重要な出来事である.
- オーガニック・カーボン・セベストレーション (OAEs),特にオーガニック・カーボン・セベストレーション (OAEs) のトリガーは,まだはっきりしていない.
研究 の 目的:
- OAE2.2のトリガーメカニズムを調査する.
- OAE2発症と一致するマグマチズムの直接的なプロキシを特定する.
- OAE2.2の際に海水中のオスミウムの起源を決定する.
主な方法:
- 海洋水のオスミウムイソトープ比を2つの遺跡の有機豊富な堆積物で分析した.
- 2つのコンポーネントの混合方程式の適用.
- オスミウム同位体データと炭素同位体記録の比較.
主要な成果:
- OAE2の発生時またはその前に,海洋オスミウム同位体記録の急激な変化.
- 海水オスミウムの97%以上は,OAE2.2の間にマグマ的起源であった.
- マグマティズムと有機炭素の埋葬の間に最大23 kyrの時間遅れがあります.
結論:
- 大規模なマグマ脈拍がOAE2.2を誘発した可能性が高い.
- マグマ活動が先行し,潜在的に重要な有機炭素埋葬を開始した.
- オスミウムイソトープデータは,マグマチズムとOAE2.2との間の直接的な関連性を示しています.
関連する概念動画
Global Climate Change
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
The Fossil Record
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
Diversity of Archaea III
Crenarchaeota, a prominent phylum of Archaea, is remarkable for its ability to thrive in extreme environments characterized by high temperatures and acidity. These microorganisms inhabit sulfuric hot springs, volcanic systems, and submarine hydrothermal vents, where temperatures often exceed 100°C. The unique adaptations of Crenarchaeota not only allow survival under such extreme conditions but also provide insights into the mechanisms of life in primordial Earth-like environments.Morphological...
Origin of Photosynthesis
Photosynthesis represents a fundamental biological process that transformed Earth's atmosphere and paved the way for complex life. Emerging roughly 3.4–3.8 billion years ago, the earliest photosynthetic organisms harnessed light energy to produce organic compounds. These anoxygenic phototrophs used electron donors like hydrogen sulfide (H₂S) or ferrous iron (Fe²⁺), rather than water, and did not release molecular oxygen (O₂) as a byproduct. Various groups, including green sulfur and purple...
Marine Microbial Ecology
Marine microbial ecosystems are shaped by distinct physicochemical limits, including high salinity, low nutrient availability, and fluctuating oxygen levels. These conditions favor smaller microbial cell sizes, which maximize their surface-to-volume ratio for efficient nutrient uptake.Microbial activity and community composition are closely linked to biogeochemical cycles, particularly in dynamic environments like estuaries, where halotolerant microbes thrive in response to variable salinity...
Deep Sea Microbial Ecology
The deep ocean and its underlying sediments represent vast, largely unexplored microbial habitats that extend far beyond the sunlit photic zone. The photic (euphotic) zone typically spans the upper ~100–200 meters of pelagic waters in the open ocean, but its depth varies geographically and seasonally, where sufficient light supports photosynthetic life. Below this lies the deep sea, spanning roughly 1000–6000 meters (bathypelagic to abyssal zones), with deeper hadal trenches extending beyond...


