恐竜の登頂は,トライアス・ジュラスの境界にあるイリジウム異常と関連している

P E Olsen¹, D V Kent, H-D Sues

¹Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.

Science (New York, N.Y.)

|May 23, 2002

まとめ

大型のセロポッド恐竜は,トライアス・ジュラスの絶滅の後に急速に多様化し,おそらくボリド衝突によって引き起こされた. この出来事は,恐竜が支配する生態系を確立し,1億3,500万年間存続した.

科学分野:

パレオントロジー・パレオントロジー
地質学地質学地質学
恐竜の古生物学について

背景:

トライアス紀・ジュラ紀 (T-J) の境界は,絶滅と野生動物の転移の重要な期間を示しています.
恐竜の出現のタイミングと要因を理解することは,メソゾイク時代の生態系を理解するために極めて重要です.

研究の目的:

大型のセロポッド恐竜の出現とT-Jの大量絶滅の間の時間的関係を分析する.
この絶滅の出来事の原因として,潜在的な地球外衝突を調査する.

主な方法:

北米の70以上の地域からテトラポッドの足跡と骨格物質の分析.
イリジウム異常の地球化学分析.
環境の変化を検出するためのパリノロジック分析 (胞子数).

主要な成果:

大型のセロポッド恐竜は,T-J境界から<1万年,最後のトライアス紀の分類から<3万年後に現れた.
この急速な回転は,陸上の大量絶滅,イリジウム異常,そしてフェルン胞子スパイクと一致しました.
恐竜の多様性は,境界後10万年以内に安定し,恐竜の優位性を確立しました.

結論:

ボライド衝突がT-J大量絶滅の原因と,その後のセロポッド放射の原因であると強く示唆されています.
T-J境界イベントは,北米東部で長続きする恐竜が支配する生態系の確立につながった.

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