まとめ
3400万年前の大規模な隕石の衝突が絶滅を引き起こした可能性があり,カリブ海の深海の中核で発見されたイリジウムに富んだ堆積物とマイクロテクタイトがそれを証明しています.
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
- 惑星科学 惑星科学
背景:
- 深海の堆積物核は,地球の歴史の貴重なアーカイブを提供します.
- パレオゲン時代は,重要な地質学的および生物学的出来事を経験しました.
- 隕石の残骸は,地質学的な出来事を年代測定し,衝突クレーターを特定するために使用することができます.
研究 の 目的:
- 約3400万年前の大量絶滅の原因を調査する.
- カリブ海深海のコアのユニークな堆積層の組成を分析するために.
- 地質学的発見と生物学的絶滅を相関させる.
主な方法:
- 堆積物コアの分析
- イリジウム濃縮による地質化学分析
- マイクロテクタイトの識別と年代測定
- 絶滅パターンのための放射性化石の分析
主要な成果:
- 隕石のイリジウムで高度に濃縮された明確な堆積層が特定されました.
- このイリジウム層は,北米のマイクロテクトイトの下で見つかり,その年代は3440万年前とされています.
- イリジウム層は5つの主要な放射性菌種の絶滅に一致した.
結論:
- この発見は,約3400万年前に大規模な隕石が衝突したことを示唆している.
- 衝突事故は,観測されたマイクロテクタイトとイリジウム異常を発生させた可能性が高い.
- この衝突が,観測された放射性菌群の大量絶滅の原因として提案されている.
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