まとめ
イリジウムの異常とマイクロテクタイトは,3400万年前に大きなボリドが衝突したことを示唆しています. この出来事は,同時にイリジウムの堆積と放射性鳥類と哺乳類の大量絶滅を引き起こした可能性がある.
科学分野:
- 地質化学 地質化学
- パレオントロジー・パレオントロジー
- インパクトクレーター研究
背景:
- イリジウム異常は,地球外生命体の衝突と関連している.
- カリブ海の中核 (DSDPサイト149) で発見されたマイクロテクタイトは,北米のテクタイトフィールドと関連しており,約3400万年前のものである.
- このマイクロテクタイトの地平線は,5つの放射性生物種の絶滅と一致しています.
研究 の 目的:
- マイクロテクタイト層で発見されたイリジウム異常の原因を調査するために.
- イリジウム異常,マイクロテクタイト,および潜在的な大量絶滅の出来事の間の関連性を調査する.
主な方法:
- 深海掘削プロジェクトサイトからの深海コアサンプル分析 149.
- イリジウム濃度の地化学分析.
- マイクロテクタイト層と,既知の地質学および古生物学的データとの相関.
主要な成果:
- イリジウム異常は,マイクロテクタイトレベルと一致して検出されました.
- イリジウムは,マイクロテクタイトと同時に堆積した塵雲から来ている可能性が高いので,ボリド衝突が示唆される.
- 衝突はおよそ3400万年前と推定されている.
結論:
- イリジウム異常,テクトイト,およびマイクロテクトイトは,3400万年前の大型ボリデ衝突イベントの強力な証拠を提供します.
- この衝撃は,放射性放射性生物の絶滅を引き起こし,陸上の哺乳類の大量絶滅に寄与した可能性がある.
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