まとめ
クリノピロキセン鉱物,特にダイオプシドとオムファシートは,高レベルのカリウム (K) を結晶構造に組み込み,鉱物学の以前の仮定に異議を唱えます. この発見は,クリノピロキセンが地球のマントルのカリウムの主要な宿主である可能性があることを示唆しています.
科学分野:
- ミネラロジーは,鉱物学です.
- 地質化学 地質化学
- クリスタルグラフィーです.
背景:
- 伝統的なピロキセンの結晶化学は,カリウム (K) がピロキセンの構造に組み込むには大きすぎると仮定しています.
- 以前の研究では,地球マントルのKにとって重要な宿主としてのクリノピロキセンは認められなかった.
研究 の 目的:
- ダイヤモンド内で発見されたクリノピロキセンのインクルージョンに高カリウム含有量の存在と影響を調査する.
- Kの組み込みに関するピロキセンの結晶化学の確立された理解に挑戦し,精錬する.
主な方法:
- 分析伝送電子顕微鏡 (TEM) を用いて,結晶構造をイメージした.
- 電子マイクロプローブ分析 (EMPA) を使用して,K含量を含む化学組成を決定しました.
- 単結晶X線 difraktion (XRD) データは,ユニット細胞のパラメータと結晶構造の洞察を提供した.
主要な成果:
- 高カリウム含有量 (K2Oの重量1.5%まで) は,ダイヤモンドからのダイオプシドおよびオムファシット含有物で確認されました.
- これらのK-ベアリングクリノピロキセンは,高度の結晶の完全性と異常な大きさの単細胞体積を示しています.
- TEMイメージングは,Kが豊富な領域で欠陥のない構造を明らかにし,Kを固体溶液でサポートしました.
結論:
- ディオプサイドやオムファサイトを含むクリノピロキセンは,これまでの考えに反して,大量のKを固体溶液に収納することができる.
- クリノピロキセンは,地球のマントル内のKにとって潜在的に重要な宿主として特定されています.
- この発見は,いくつかのダイヤモンドとクリノピロキセンのインクルージョンが,K濃縮されたマントルの環境で形成された可能性があることを示唆している.
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