ジュラ紀の砂岩は,熱帯大西洋の熱帯大西洋から来ている
まとめ
研究者らは,南米の深淵の縁の最も古い堆積物を発見しました. この浅瀬の砂岩はジュラ紀後期に遡り,大西洋の早期裂け目や海底形成の洞察を提供している.
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
- 海洋学 海洋学 海洋学
背景:
- 南米の深淵の境界は,大西洋の初期の進化を理解するための境界線を表しています.
- この地域の堆積物記録は,古地理学的および構造学的歴史の再構築に不可欠です.
研究 の 目的:
- 南米の深淵の縁で発見された最も古い堆積物を特定し,特徴づけること.
- 新たに回収された深海の堆積物の堆積環境と年齢を決定する.
主な方法:
- 4400メートルの深さでデメララ高原から堆積物核の回収.
- 堆積物の組成分析 (カルケアの砂岩,粒子の大きさ).
- パリノモルフやモルスクのプリズマを用いたバイオストラティグラフィック分析.
主要な成果:
- 南アメリカの深淵の縁からこれまでに採取された最も古い堆積物の回収.
- 浅水,粗粒,石灰岩砂岩の識別. 浅水,粗粒,石灰岩砂岩の識別. 浅水,粗粒,石灰岩砂岩の識別. 浅水,粗粒,石灰岩砂岩の識別.
- 沈殿物の年代付けはジュラ紀末期 (またはおそらく白紀初期) に遡る.
結論:
- 回収された砂岩は,ジュラ紀末期における大陸付近海における浅水堆積を示している.
- この発見は,大西洋の裂け目の初期段階と,新たに形成された海洋盆地の後の沈没の証拠を提供します.
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