地殻 の 下部 から 採取 さ れ た 青い ボロン を 含有 し た ダイヤモンド
Evan M Smith1, Steven B Shirey2, Stephen H Richardson3
1Gemological Institute of America, New York, NY, USA. evan.smith@gia.edu.
Nature
|August 3, 2018
まとめ
青いダイヤモンドは 深いマントルのリサイクルを示しています 低層マントルに沈殿し,ダイヤモンドの形成と地殻の元素のリサイクルを容易にする.
科学分野:
- 地化学
- ミネラロジー
- ペトロロジー
背景:
- プレート構造は地球のマントルに 表面物質の循環を促します
- 浅い放出深さのため,潜水した地殻の成分を追跡することは困難です.
- ボロンは地殻に豊富に存在し, 深いマントルのダイヤモンド形成液体に見られます.
研究 の 目的:
- 深層マントルのダイヤモンドの ボロンの起源を特定するために
- IIb型ダイヤモンドの結晶化の地質学的設定を特定する.
- 深層マントルのプロセスにおける海底石層の役割を明らかにする.
主な方法:
- ボール含有ダイヤモンド内の鉱物含有物の分析.
- 高圧/高温実験で鉱物の安定性を決定する.
- 潜水過程の地化学モデリング
主要な成果:
- ボロン含有ダイヤモンドは 独特の鉱物組成を含んでいます
- これらのアセンブラージは,より低いマントルの深さで変形した海洋石層に安定した前駆者を示しています.
- 蛇形化した海洋の石層からのボロンは,深層の液体に吸収され,放出されます.
結論:
- タイプIIbのダイヤモンドは,下層マントルから発生し,知られている最も深いダイヤモンドの1つです.
- 海水で蛇形化した海洋の石層は 深いマントルにボロンの再利用の経路を提供する.
- この研究は,地殻の要素の深層マントルのリサイクルのための実行可能なメカニズムを示しています.
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