まとめ
クレタ紀中期の古磁気データは,ユーラシアと北米に似た太平洋プレートのゆっくりとした動きを明らかにしています. これは,マントルの羽根が,この期間に太平洋プレート構造に影響を与えたことを示唆している.
科学分野:
- パレオマグネティズム (古磁気学) とは
- プレート・テクトニクス (プレート・テクトニクス)
- ジオダイナミクスは地力学です.
背景:
- クレータ紀中期の古磁気データは,太平洋プレート運動が遅い (<0.3°/年) ことを示している.
- この動きは,同じ期間にユーラシアと北米で観測された極の停滞を反映しています.
- オントン・ジャワ高原の形成は,アプティアの初期の大規模な火山のエピソードを表しています.
研究 の 目的:
- 紀元初期から紀元中期までの太平洋プレート運動を調査する.
- プレートテクトニクスと,オントン・ジャワ高原形成などの主要な火山の発生との関係を決定する.
- マントルプーム火山活動が白期太平洋盆地構造に及ぼす影響を評価する.
主な方法:
- クレータ紀中期の山脈からの古磁気データの分析.
- 古代磁気記録に基づく太平洋プレート運動の再構築.
- 太平洋プレート運動とユーラシアと北米の同時代のプレート運動の比較.
主要な成果:
- 太平洋プレート移動は,クレタセア初期から中期にかけてゆっくり (<0.3°/年) であった.
- 初期のアプティアン火山のエピソードとオントン・ジャワ高原の形成に先行したプレート運動の変化を示唆する証拠はほとんどありません.
- 太平洋プレートに隣接する海洋プレートは,火山活動中に急速に移動した.
- 太平洋プレートの北向きの動きは,火山活動が停止した後に始まった.
結論:
- マントルプームの火山活動により,白期の太平洋盆地におけるプレート構造が制御された可能性が高い.
- 火山活動の停止は,太平洋プレートの急速な動きの始まりを先行した.
- プレート運動のダイナミクスは,白亜紀のマントル羽の活動によって著しく影響を受けた.
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