衝突によって引き起こされた可能性のある白亜紀・古亜紀の境界におけるデッカの火山の状態の変化
Paul R Renne1, Courtney J Sprain2, Mark A Richards3
1Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA. Department of Earth and Planetary Science, University of California-Berkeley, Berkeley, CA 94720, USA. prenne@bgc.org.
Science (New York, N.Y.)
|October 3, 2015
まとめ
クレータ紀末期の大量絶滅は,ボリドの衝突とデッカントラップの洪水火山活動と関連している可能性がある. 新しいデータによると,デッカンの罠は
科学分野:
- 地理科学
- 古生物学
- 地化学
背景:
- クレータ紀末期の大量絶滅は2つの主要な仮説に起因する:ボリド衝突と洪水火山活動.
- デッカンのトラップは,大きな火山地帯で,重要なバザルトの洪水イベントを表しています.
- 絶滅パターンを理解するには これらの出来事の相互作用を理解することが重要です
研究 の 目的:
- チクスルブ・ボリドの衝突と デッカン・トラップの洪水火山の間の時間的関係を調査する
- この2つの主要な地質現象が 遺伝的に関連し クレータ紀末期の大量絶滅に 影響を与えたかどうかを判断する
- 火山活動が絶滅後の生態系回復に及ぼす影響を評価する.
主な方法:
- 高精度 (40) Ar/(39) Arのジオクロノロジーは,デカントラップの火山岩の年代測定に使用されました.
- 地質化学分析により,マグマ系が特徴づけられました.
- 高精度年齢データとチクスルブ衝突のタイミングの相関関係
主要な成果:
- 高精度 (40) Ar/(39) Arのデータは,デッカントラップスのマグマ系における状態変化を明らかにしています.
- この状態のシフトは,チクスルブ衝突と末期クレタセウスの大量絶滅とほぼ一致した.
- デッカン・トラップの総体積の約70%は,衝突から約5万年以内に開始されたこのシフトの後,より大規模なエピソード的な噴火で挤出されました.
結論:
- デッカントラップの洪水火山活動とチクスルブ衝突は遺伝的に関連している可能性が高い.
- 衝突はデッカントラップのマグマ系に重大な変化を引き起こし,火山活動が加速した.
- 急速な火山活動が 収束するまで 海洋生態系の回復は 抑制されていたようです
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