まとめ
有意な負の重力異常は,ガラパゴス諸島の下にある低密度の質量を示しています. この発見は,地球上の"ホットスポット"の可能性を示唆しています.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 地質学 地質学 地質学
- 海洋学 海洋学とは
背景:
- ガラパゴス諸島は,著しい重力異常を呈している.
- この異常は,残留負のフリーエアとブーゲール値が80ミリガールを超えると特徴付けられています.
- 異常は,より広い正の重力場に重ねられています.
研究 の 目的:
- ガラパゴス島で観測された重力異常の根本的な原因を調査する.
- 異常の原因となる質量分布の性質と深さを決定する.
- マントルの羽根やホットスポットなど,異常に寄与する潜在的な地質学的プロセスを調査する.
主な方法:
- 残留のネガティブフリーエアとブーゲーの重力異常の分析.
- 地下密度の変動を推論するために重力データを解釈する.
- 熱異常の可能性を評価するためのジオダイナミックモデリング.
主要な成果:
- ガラパゴス諸島上空では,少なくとも80ミリガールの値を持つ明確な負の重力異常が確認されています.
- 異常の軸は東に傾き,同じ方向に深まり,指向的な源を示唆しています.
- データは,群島の下の地殻または上層マントルの内部に低密度の質量の存在を強く示唆しています.
結論:
- 観測された重力異常は,ガラパゴス諸島の下にある低密度の大体と一致しています.
- この低密度の質量の合理的な説明は,地殻マントルの"ホットスポット"に関連する熱膨張である.
- ホットスポット仮説を確認するために,さらなる地質学的および地化学的な研究が必要である.
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