まとめ
ホーペンとステランのバイオマーカーの炭素13同位体分析は,太平洋のフォティックゾーン層分化のミオセンの変化を明らかにしています. この有機地化学データは,無機の記録と相関し,混合から層分かれしたフォトゾーンへの移行を示しています.
科学分野:
- 地質化学 地質化学
- パレオセアノグラフィー
- オーガニック・ジオケミストリー
背景:
- ホーパンやステランなどのバイオマーカーは,古代の環境の地化学的サインを保存します.
- モンテレー形成は,ミオセンの古海洋学的条件の豊富な記録を提供します.
研究 の 目的:
- ミオセンの海洋学的な変化を特定バイオマーカーの炭素-13 ((13) C) イソトープ比を用いて調査する.
- 有機地化学データを無機古気候のプロキシと相関させる.
主な方法:
- Monterey Formationのサンプルから得られたステランとホーパンのバイオマーカーの炭素13 ((13) C) 含有量の分析.
- バイオマーカーの同位体データと酸素-18 (デルタ) の記録の比較.
主要な成果:
- 浅瀬フォティックゾーン生物からのステランは,ミオセーン全体で有意な同位体変化を示さなかった.
- ホーパンは,光帯の底にある細菌から派生したもので,ミオセンの中期と後期に13C濃度が低下していた.
- これらの有機的発見は,ミオセンの無機 (デルタ) 記録と並行しています.
結論:
- バイオマーカーの13Cの傾向は,ミオセンの移行を反映しています. 太平洋のよく混合したから層状のフォティックゾーンへ.
- このデータは,ミオセンの中期にフォティックゾーンの底辺で二酸化炭素に富んだ水質が形成されたことを示唆している.
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