クレータ紀・パレオゲン紀の境界線周辺の重要な出来事の時間スケール
Paul R Renne1, Alan L Deino, Frederik J Hilgen
1Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA. prenne@bgc.org
まとめ
Chicxulubの衝突は,白亜紀-旧紀の大量絶滅と一致し,急速な生態系シフトを引き起こしました. 証拠によると,大気中の炭素循環は5000年以内に回復し,海洋盆地よりもはるかに速く回復しました.
科学分野:
- 地質学 地質学 地質学
- パレオントロジー・パレオントロジー
- 地球科学 地球科学 地球科学
背景:
- 大量絶滅は,地球の歴史における重要な進化の転換点を表しています.
- クレータ紀・旧紀 (K-Pg) の境界線は,生物学的循環の重要な期間を示しています.
- Chicxulubボリドの衝突は,K-Pg大量絶滅のイベントの主要な仮説である.
研究 の 目的:
- Chicxulubの衝突とK-Pgの大量絶滅の間の時間的同期を確立するために.
- 大気中の炭素循環の混乱の持続時間と回復時間スケールを調査する.
- 衝突事故の後に哺乳類動物群の持続性を評価する.
主な方法:
- アルゴン-アルゴン ((40) Ar/ ((39) Ar) による地質年代測定.
- クレタセオス・パレオゲノム境界に関連する地質層を分析する.
- 西部のウィリストン盆地における哺乳類の化石記録を調査.
主要な成果:
- Chicxulubの衝突とK-Pgの大量絶滅の間の同期は32,000年以内に確立されました.
- 大気中の炭素循環の乱れは5000年未満に続き,急速に回復した.
- 低多様性の哺乳類動物群は,衝突後約2万年間存続した.
結論:
- Chicxulubの衝撃は,生態系の重要な状態のシフトを誘発した可能性がある.
- 炭素循環の急速な回復は,回復力メカニズムが圧倒されたことを示唆しています.
- K-Pgの大量絶滅は,Chixulubの衝突と密接に関連しており,深刻な生物学的結果をもたらしました.
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