アキモトイト-ブリッジマニトの移行によって引き起こされた660kmの不連続性
Artem Chanyshev1,2, Takayuki Ishii3,4, Dmitry Bondar5
1Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany. artem.chanyshev@uni-bayreuth.de.
Nature
|January 6, 2022
まとめ
660キロメートルの地震の断絶
科学分野:
- 地理学
- 鉱物物理学
- 高圧地化学
背景:
- 660キロメートルの地震の断絶は 地下マントルと 移行領域の境界線を示しています
- これはしばしばリングウッドイットからブリッジマニットおよびフェロペリクラゼへのスピネル後の移行に起因する.
- この不連続性は,特に潜水地帯の下では低下しており,現在のモデルでは完全に説明できない現象です.
研究 の 目的:
- スピネル後とアキモトイト-ブリッジマニトの移行の相境界を正確に決定する.
- これらの移行の温度依存とクラペイロンの傾きを調査する.
- 660キロの不連続性の原因を 再解釈する
主な方法:
- 高圧合成のためのマルチアンボールの実験を活用した.
- 正確な相識別と境界の決定のために,in situ X線 difraktionを使用しています.
- 段階均衡の定義を厳格に遵守する実験に焦点を当てた.
主要な成果:
- スピネル後の移行境界は,最小限の温度依存を示しています.
- アキモトイト-ブリッジマニトの移行は,周囲のマントルの地熱よりも低い温度で急な負の境界斜率を示します.
- この発見は 660キロメートルの不連続性の深さに関する以前の解釈に 異議を唱えます
結論:
- 寒い潜水地帯の下の660キロメートルの不連続性の沈殿は,アキモトイト-ブリッジマニット移行に起因する.
- この移行の急激な負の傾きは,スラブの停滞につながる重要な上昇傾向を示唆しています.
- この研究は,マントルの動力学と潜水過程の理解を洗練します.
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