火山の縁の形成における裂け目の歴史の重要性
John J Armitage1, Jenny S Collier, Tim A Minshull
1Department of Earth Science & Engineering, Imperial College London, London SW7 2AZ, UK. j.armitage@imperial.ac.uk
Nature
|June 19, 2010
まとめ
大陸の裂け目とマグマティズムは結びついているが,マントルの温度は唯一の要因ではない. 以前の拡張エピソードは,大陸の分裂中の火山活動に大きく影響し,世界中で様々なマグマチズムを説明しています.
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:
- 裂け目とマグマティズムは重要な地質学的プロセスであり,それらの関係は惑星の表面進化を理解するために重要である.
- マントルの気温は,以前は,主に北大西洋のデータに基づいて,大陸の崩壊中のマグマ的産生を制御する主な要因と考えられていた.
- インド洋の北西部のような,他の裂け目の縁からの観測は,この見解に異議を唱え,断裂イベントとの明確な関連にもかかわらず,低いマグマチズムを示しています.
研究 の 目的:
- 断裂した大陸の縁のマグマチズムの矛盾する観測を調和させるため.
- 裂け目の発生時の現在のマグマの産生に対する過去の構造的出来事の影響を調査する.
- マグマティズムを異なるリフト環境で比較するための数値モデルを開発する.
主な方法:
- 数値モデルの適用で,リフトのプロセスをシミュレートする.
- モデルに,前回の地殻拡張のエピソードの影響を明示的に含めること.
- インド洋の北西および北大西洋のマグマチズムの比較分析.
主要な成果:
- 裂け目の縁のマグマティズムは,マントルの温度と拡張の歴史の両方によって制御されます.
- 以前の拡張エピソードは,その後の裂け目の際に溶融生成を大幅に抑制または強化することができます.
- このモデルは,インド洋の北西の縁で観察された低いマグマティズムをうまく説明しています.
結論:
- 大陸の崩壊マグマティズムは,マントルの温度にのみ依存するものではありません.
- 継承された拡張的歴史は,裂け目の間におけるマグマティズムのスタイルと量を制御する重要な要因です.
- この発見は,世界中の裂け目の縁のマグマの変動に関する以前に謎めいた観測を解決します.
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