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Updated: Jul 11, 2026

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Negative Additive Manufacturing of Complex Shaped Boron Carbides
Published on: September 18, 2018
まとめ
海洋島の玄武岩は,一貫したボロン同位体比を有する. 対照的に,中洋のの玄武岩と後方弧盆の玄武岩は,地殻の同化による可能性が高い,変動する比率を示しています.
科学分野:
- 地質化学 地質化学
- イソトープ地球化学 イソトープ地球化学
- ペトロロジー・ペトロロジーとは
背景:
- 火山ガラスのボロン同位体比は,地球のマントルと地殻の過程についての洞察を提供します.
- 海洋島ベースルト (OIBs) は均質なボロンイソトープ組成を示しているが,海洋中部のリッジベースルト (MORBs) とバック・アーク・ベーシン・ベースルト (BABBs) はより大きな変動を示している.
研究 の 目的:
- 様々な玄武岩種で観察される異なるボロン同位体比の背後にある理由を調査する.
- マントル由来の溶融物におけるボロン同位体シグネチャーに対する地殻の同化の影響を決定する.
主な方法:
- OIB,MORB,BABBからの火山ガラスのボロン同位体比の分析.
- マントルの分化と地殻の同化過程におけるボロン同位体の分化のモデリング.
主要な成果:
- OIB の火山ガラスは,一貫して -9.9 ± 1.3 per mil (NBS 951 と比較して) 周辺のボロン同位体比を示しています.
- MORBとBABBは,より高く,より変動するボロン同位体比を示しています.
- 変異した玄武岩地殻のわずかな同化でさえ,溶融物におけるボロン同位体比を大幅に変化させます.
結論:
- 地殻アシミレーションは,MORBsとBABBsの上昇したおよび変動するボロン同位体比に寄与する主要な要因です.
- 原始的なマントルは,おそらく -10 ± 2 per mil のボロンイソトープ比を有していた.
- ボロンイソトープ比は,重要なマントルの分化過程で比較的分断されていないままである.
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