中大西洋の赤道の下にある薄いマントルの移行地帯
Matthew R Agius1,2, Catherine A Rychert3, Nicholas Harmon3
1Ocean and Earth Science, University of Southampton, Southampton, UK. matthew.agius@soton.ac.uk.
Nature
|January 28, 2021
まとめ
地上と地下のマントルの間の物質の移転を容易にし,以前の仮定に挑戦しています. この発見は,マントル全体のコンベクションが以前に理解されたよりも重要であり,山脊が重要な役割を果たしていることを示唆しています.
科学分野:
- 地理学
- 地震学
- 地球科学
背景:
- 地球のマントルの層間の物質の移転は,その進化にとって極めて重要です.
- スラブ沈殿とマントルの羽根は移転場所として知られていますが,中海の山脊は重要と考えられませんでした.
- 海中での直接的な測定は難しい.
研究 の 目的:
- マントルの物質の移転における海中山脈の役割を調査する.
- 中大西洋の下のマントルの移行地帯を境界する地震の不連続をイメージする.
- 全マントルのコンベクションへの影響を評価する.
主な方法:
- 地震波の変換に利用された受信機能.
- 海底の地震データを 分析した
- 410kmと660kmの深さで 解読された地震の不連続性
主要な成果:
- 660 kmの不連続性の上昇と410 kmの不連続性の沈下が観測され,マントルの移行領域の薄まりを示している.
- 偶然の 緩やかなシェア波の速度は 浮上物質を示唆している
- 古い海底と比べると 地震速度が遅い
結論:
- 中洋の山脊は下から上へとマントルの物質が 移動する場所です
- この転送は継続的にまたは断続的に発生します.
- 斜面上流はマントル全体のコンベクションに寄与し,潜在的にスラブ下流を均衡させる.
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