まとめ
南洋の冷却現象は,氷河に覆われた砂とプランクトンの多様性が低いことで特徴付けられ,エオセーンとオリゴセーンに発生しました. その後のミオセンの温暖化により,多様性が増加し,氷河に覆われた物質が減少し,南極の氷河が持続することを示唆しています.
科学分野:
- パレオセアノグラフィー
- 海洋地質学 海洋地質学
- マイクロパレオンタロジーとは
背景:
- ケノゾイク時代は,気候の変動が顕著であった.
- 南洋の古海洋学を理解することは,世界の気候の再構築に不可欠です.
- プランクトン系フォラミニフェラは,海洋状態の敏感な指標である.
研究 の 目的:
- 南洋の気候とラフティングの関係について調査する.
- ケノゾーイク時代のパレオセアノグラフィの条件を再構築する.
- 南極氷河の長期的な安定性を評価する.
主な方法:
- 南太平洋の18のケノゾイク期深海の堆積物核の分析.
- アイスラフトの砂の含有量の調査.
- プランクトンの動物多様性と種の構成の評価.
主要な成果:
- 降温現象 (低エオセーン,中高エオセーン,オリゴセーン) は,氷河による砂の増加と,フォアミニフェラル多様性の減少と相関していた.
- 下次ミオセーンと中期ミオセーンにおける温暖化傾向は,氷河に覆われた砂の減少とより高い種の多様性によって示されています.
- いくつかのミオセンの間隔で氷に覆われた砂の欠如は,一時的な氷のない状態または減少した氷河出力を示唆しています.
結論:
- 南大洋の気候は,ケノゾイク期を通じて,冷却と温暖化の異なった段階を経験しました.
- 南極大陸の氷河化は,ケノゾイク期の大部分の間,持続的な特徴でした.
- プランクトンのフォアミニフェラル多様性は,古海洋学的な温度変化の信頼できるプロキシとして機能します.
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