コロンビア川の洪水ベースルトとオレゴン州北東部のウォロワ山脈の上昇に起因する石層の不安定性
T C Hales1, D L Abt, E D Humphreys
1Department of Geological Sciences, 1272 University of Oregon, Eugene, Oregon 97403, USA. thales@uoregon.edu
Nature
|December 13, 2005
まとめ
コロンビア川の玄武岩 (CRB) は,イエローストーンのホットスポット・トラックではなく,ウォロワ山脈の近くから発生した. マントルの下流と分離したプラトン系根は,CRBのマグマティズムと上昇を説明する.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 火山学 火山学とは
- 地質化学 地質化学
背景:
- 洪水ベースルトは,ホットスポット開始と関連しています.
- コロンビア川の玄武岩 (CRB) は,イエローストーンのホットスポットに関連した最大の洪水玄武岩です.
- CRB源は,ウォロワ山脈の近く,計画されているホットスポット軌道から500km北にある.
研究 の 目的:
- コロンビア川のベースルト (CRB) の源泉と上昇メカニズムを調査する.
- ウォロワ山脈地域の下にあるマントルの構造を決定する.
- マントルの特性は,CRBの位置と表面変形と相関する.
主な方法:
- マントルの地震速度の構造分析.
- 溶岩流の侵食補正された標高マップを作成.
- ウォロワ山脈地域の地質地図作成.
主要な成果:
- ウォロワ山脈の下,マントルの融解量が減少した地域を特定しました.
- ウォロワ山脈を中心に200km幅の地形上昇を観測した.
- ウォロワ山脈では,噴火前の沈下が記録され,その後にシン噴火と長期の上昇が続いた.
結論:
- コンベクティブ下流と密度の高いプラトン根の分離は,CRBマグマティズムを説明する.
- このメカニズムは,観測された表面の上昇と融解によるマントルの枯渇を説明する.
- ウォロワ山脈地域は,洪水ベースルトの起源を理解するための重要な地域として機能しています.
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