地球の上部マントルの流域の同位体描写
Christine M Meyzen1, Janne Blichert-Toft, John N Ludden
1Laboratoire des Sciences de la Terre, CNRS UMR 5570, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, 46 Allée d'Italie, 69364 Lyon cedex 07, France. christine.meyzen@ens-lyon.fr
Nature
|June 29, 2007
まとめ
地球 地球 地球 地球 地球
科学分野:
- 地質科学は地質科学である.
- 地球科学 地球科学 地球科学
背景:
- 地球のマントルはプレート構造において重要な役割を果たしています.
- マントルのコンベクションと材料のリサイクルのプロセスを理解することは,地質学的現象を理解するために不可欠です.
- 沈下した海洋プレートの上層マントルへの逆流を制御するメカニズムは完全に理解されていません.
研究 の 目的:
- 地化学的サインを分析することによって上層マントルの補充モードを調査する.
- 地化学領域とマントルのコンベクションとの関係をマッピングする.
- 大陸のケールが上層マントルの補充プロセスに及ぼす影響を理解する.
主な方法:
- 南西インド山脈沿いの長寿命放射性同位体,特にハフニウム同位体の分析.
- 同位体データを用いて地化学領域を区切る.
- 地化学ドメインを地震データと梅の活動と相関させる.
主要な成果:
- 異なる海洋地方における上層マントルの対照的な補充モードを特定した.
- 南西インド山脈に沿ってハフニウム同位体組成の急激な移行が観察され,異なるマントル領域を示しています.
- インド州では下層マントルの同位体の影響,南大西洋州では上層マントルの物質による汚染の証拠が見つかりました.
- 上層マントルのリフィーリングは,南アフリカの下の異常とアファーの羽根と関連しています.
- 大陸のキールからの粘着性の引き寄せが,大西洋とインド海域の上昇を遅らせ,局所化することを実証しました.
- 太平洋の域でより広大でより急速な上昇が観察されました.
結論:
- 放射性同位素を用いてマッピングされた地化学領域は,上層マントルの補充メカニズムが対照的であることを示している.
- 大陸のキールはマントルの流れに大きく影響し,局所的な上流につながる.
- 太平洋領域は,大陸の影響がないため,より効率的で広範なマントルの補充を示しています.
- この研究は,マントルのコンベクションとプレートテクトニクスを支配するダイナミックなプロセスについての洞察を提供します.
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