魚の残骸の酸素イソトープ (エル・ケフ,チュニジア) によって示された最古のパレオゲン温暖化
K G MacLeod1, P C Quinton2, J Sepúlveda3
1Department of Geological Sciences, University of Missouri, Columbia, MO, USA. macleodk@missouri.edu.
まとめ
Chicxulubの衝突は 温室効果の温暖化を 引き起こしたのかもしれませんが データは稀でした 魚の残骸の新しい分析は ~5°Cの温度上昇を明らかにし,衝突による温暖化仮説を支持しています.
科学分野:
- 古代気候学
- 地化学
- 衝突クレーター
背景:
- 温室効果はチクスルブ衝突の 予測された結果ですが 支持するデータは稀です
- 適切な古熱計の断面がないため,衝突効果の理解が困難です.
- 以前の研究では,従来の古熱測定と短期変化の解像度に関する資料が不足していました.
研究 の 目的:
- 衝突による温室効果温暖化の可能性を調査する
- 温室効果温暖化に関するデータ不足を 解決するために
- クレタセオス/ペロゲーノスの境界を越えた古気温の変化を分析する.
主な方法:
- 魚の残骸の酸素同位体の分析 (リン酸微化石)
- 遺伝的変化に耐える素材を使用した.
- チュニジアのエル・ケフにある白亜紀/旧紀境界のグローバル・ストラトタイプセクションとポイントから採取したサンプル.
主要な成果:
- 酸素同位体値が1ミリあたり約1値低下することが観察された.
- この同位体シフトは,推定5°Cの温暖化に対応しています.
- 温暖化傾向は白亜紀/旧亜紀の境界から始まり,約300センチメートル (約10万年) の範囲に及ぶ.
結論:
- 観測された5°Cの温暖化パターンは,衝突による温室効果温暖化に関する予想と一致しています.
- 魚の残骸は,ダイアゲネシスの影響を受けた部分で古熱測定のための有効な方法を提供します.
- この研究は,チクスルブの影響と,その後の温室効果温暖化との関係を裏付ける重要なデータを提供します.
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