U-Pbは,中国の中国,ネオプロテロゾイク時代のドゥシャントゥー形成から古くなりました
Daniel Condon1, Maoyan Zhu, Samuel Bowring
1Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. dcondon@mit.edu
Science (New York, N.Y.)
|February 26, 2005
まとめ
中国にあるドゥシャントウ岩層は,6億3500万年から5億5100万年前の間に堆積し,地球規模の脱氷と一致した. その動物の化石は,主に5億8000万年未満で,頂部付近に重要な炭素同位素の遠足があります.
科学分野:
- ジオクロノロジー (Geochronology) について
- 古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
- パレオントロジー・パレオントロジー
背景:
- 中国にあるドゥシャントウ岩層は,重要な古生物学および地質学的記録を保持しています.
- その堆積のタイミングとマリノの氷河期のような地球規模の気候現象との関係は,生命の初期を理解するために極めて重要です.
- 以前の研究では,形成のための幅広い年齢範囲が示唆されています.
研究 の 目的:
- U-Pbジルコンの分析を用いて,ドゥシャントゥー形成の正確な年代を決定する.
- ドゥシャントゥオ岩層の堆積のタイミングと,地球規模の気候現象,特にマリノの氷河期の終わりを相関させる.
- ドウシャントウの生物群の年齢を制限し,関連する炭素同位体探検を調査する.
主な方法:
- U-Pbジルコンは,火山灰の床のジオクロノロジーである.
- 炭酸サンプルの炭素同位体分析.
- シーケンス・ストラティグラフィック分析.
主要な成果:
- U-Pbジルコンの年代測定は,ドゥシャントゥー形成の堆積を6億3500万年から5億5100万年前の間に置く.
- 形成の底はマリノの氷河期が終わった時期と同時期であり,同期的な脱氷を示している.
- 炭素同位体とシーケンス・ストラティグラフィックのデータによると,動物化石は5億8000万年未満であることが示唆されています.
- 大量の負の炭酸ガスの炭素同位体発散は,約5億5100万年前の最上部にあるドゥシャントウ岩層で確認されています.
結論:
- ドゥシャントゥオ岩層は,マリノの氷河期末と,その後の脱氷期間の重要な期間を記録しています.
- 年齢の制約は,この形成内の初期の動物生活のタイミングについての私たちの理解を洗練します.
- 約5億5千1百万年前の負の炭素同位体の放出は,初期の生態系に影響を与えた潜在的に世界的なイベントを表しています.
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