まとめ
北大西洋のギョート石灰岩の海底リチフィケーションは,周囲の海水との均衡状態で再結晶化が起こったことを示しています. このプロセスは,マグネシウムに富んだカルシートが,時間の経過とともにマグネシウムに乏しいカルシートに変化し,最小限の堆積を必要とする可能性が高い.
科学分野:
- 地質学 地質学 地質学
- 海洋学 海洋学とは
- イソトープ地球化学 イソトープ地球化学
背景:
- ガイオットは,独特の地質学的形成を宿すことができる水中に沈んだ絶滅した火山です.
- 海洋炭酸塩のダイアゲネシスは,水の化学と埋葬率の影響を受けます.
- 炭酸塩の酸素同位体は,その形成時の環境条件を記録する.
研究 の 目的:
- 北大西洋のガイオットのプランクトン石灰岩に影響を与えるダイアゲネティックプロセスを調査するために.
- これらの石灰岩の再結晶が海洋または気象条件下で起こったかどうかを判断する.
- 深海の炭酸塩のリチ化における海水の役割を理解する.
主な方法:
- 再結晶したプランクトン石灰岩の酸素同位体分析.
- 炭酸塩鉱物学の地球化学分析 (例えば,カルシート組成).
- 北大西洋の海水環境と同位体および化学データの比較.
主要な成果:
- 再結晶化した石灰岩は,現在の北大西洋の水域と酸素同位体の均衡状態にある.
- 証拠によると,初期段階のリチフィケーションにはマグネシウム豊富なカルシットが含まれ,それは時間の経過とともにマグネシウムに乏しいカルシットに逆転する.
- 観測されたリチフィケーションは,おそらく非常に低い堆積率の堆積率を必要とします.
結論:
- 潜水中のリチフィケーションと再結晶化は,これらのギョート石灰岩の支配的なダイアゲネティックプロセスです.
- マグネシウムが豊富なカルシットから,マグネシウムが少ないカルシットへの変換は,海底の下の長期変化の重要な指標である.
- 低堆積率の沈殿物は,炭酸基のプラットフォームで広範囲にわたる海底ダイアゲネシスを促進するために不可欠です.
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