古い山の地殻の根元にある浮力力が弱まっている
1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA. Karen_Fischer@brown.edu
Nature
|June 28, 2002
まとめ
山地殻の根は,冷却により何百万年にもわたって浮力を失い,侵食が山々を磨くにつれて地形を支える能力を低下させます. これは,古い山が,地殻の根に比べて,より小さなリリエフを持っている理由を説明します.
科学分野:
- 地質学 地質学 地質学
- 地質物理学 地質物理学とは地質物理学です.
- テクトニクス (地質学) とは
背景:
- 山の形成には地殻の加厚と深い地殻の根があり,地形を支える浮力を提供します.
- 侵食は,地質学的な活動が停止した後,表面の救済を減少させるが,地殻の根の長期的な反応はあまり理解されていない.
研究 の 目的:
- 山の地殻の根が,地質的な時間尺度で侵食による下落にどのように反応するかを調査する.
- 山の年齢,地表の浮力,地殻の根の浮力との関係を理解する.
主な方法:
- 古いと若い衝突山帯からの重力データの分析.
- 表面の浮き彫りと地殻の根の厚さの比率の比較.
- 長期の冷却と変異反応が地殻の根の浮力に及ぼす影響をモデル化.
主要な成果:
- 古い山帯は,より若い山帯と比較して,地殻の根の厚さに対する表面リリーフの比率が小さい.
- この傾向は,年齢とともに地殻の根の浮力性が低下し,冷却によって引き起こされる変形反応と一致していることから起因する.
- 質量バランスが示しているのは,大陸の石層は,何百万年にもわたって根を掘り出すのに十分なほど弱いままであるということです.
結論:
- 地殻の根の浮気力は,地質的な時間とともに冷却により著しく低下し,山の支柱に影響を及ぼします.
- 侵食により地殻の根が長期間掘り下げられる一方で,浮力力が低下すると,その上昇が制限される.
- これらのプロセスを理解することは,衝突山脈帯の進化を解釈する上で極めて重要です.
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