クォーツジートにおけるニュートン式離位クリープ:地殻下部のレオロギーへの影響
まとめ
自然と合成のクォーツジットは,ニュートン式脱位 (ハーパー・ドーン式) を通して変形し,高温と低圧力では這いていく. これは,地殻の下部が,以前考えられていたよりも低いストレスで,脱位メカニズムを通じた粘性のある液体として流れることができることを示唆しています.
科学分野:
- 地質学 地質学 地質学
- マテリアルサイエンス 材料科学
- 固体地球 地質物理学
背景:
- 地殻下部のレオロギーを理解することは,プレート構造学と地震の解釈に不可欠です.
- 以前のモデルでは,下層の地殻岩のダクティルフローのストレスの値が高くなることがしばしば想定されていた.
研究 の 目的:
- 下層地殻条件下でクォーツジットの変形メカニズムを調査する.
- ニュートン式脱位 (ハーパー・ドーン) クリープがクォーツジットで適切な温度とストレスで発生するかどうかを判断する.
主な方法:
- 自然石英石と合成石英石のサンプルを機械的に試験する.
- 変形特性を特定するための微細構造分析.
- 高温 (>1073 K) と低ストレス (<300 MPa) をシミュレートする実験条件.
主要な成果:
- 自然のクォーツサイトと合成のクォーツサイトは,ニュートンの変位 (ハーパー・ドーン) のクリープの証拠を示した.
- このクリープメカニズムは,1073Kを超える温度と300MPa未満のストレスで観察されました.
結論:
- クォーツジットは,地殻の低い条件下で,ハーパー・ドーン・クリープによって変形することがあります.
- 下層は,以前考えられていたよりも著しく低いストレスでニュートンの粘着性流体として振る舞う可能性があり,これは脱位メカニズムによって引き起こされる.
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