Fe2SiO4液体の高温XAS研究: 鉄色の鉄の調整低下
Science (New York, N.Y.)
|October 8, 1993
まとめ
X線吸収スペクトロスコピーは,結晶型ファヤライトのFe2+) コーディネーションが6から,Fe2SiO4のFe2SiO4に減少することを明らかにしています. この構造の変化は,融解の性質と地球上の元素の分割に影響を及ぼします.
科学分野:
- 地質化学 地質化学
- マテリアルサイエンス 材料科学
- ミネラル物理学 ミネラル物理学
背景:
- シリケート溶融の構造を理解することは,地質学的観測と地球内の地化学的過程の解釈に不可欠です.
- 鉄 (Fe) は多くの地質学的材料の重要な成分であり,その調整状態は溶融特性に大きな影響を与えます.
- シリケート液体中のFe ((2+) の以前のモデルには,関連する温度と圧力での詳細な構造情報がなかった.
研究 の 目的:
- X線吸収スペクトロスコピーを用いて,融解したFe(2) SiO(4) (ファヤライト) のFe(2+) の局所構造環境を決定する.
- 融解時に調整番号とFe2+) -O結合長さの変化を調査する.
- オリヴィン組成の溶解物におけるFe2+の構造モデルとその地質システムへの影響を開発する.
主な方法:
- X線吸収スペクトル検査 (XAS) は,Fe(2) SiO(4) 液体で1575 Kと10−4 GPaで実施されました.
- 分析には,液体構造の不調和を考慮することが含まれていた.
- 顕微鏡データと,結晶型ファヤライトの融点における光譜データの比較.
主要な成果:
- Fe(2) SiO(4) の液体中のFe(2+) -O結合の長さは1.98 ± 0.02 Åで,結晶型ファヤライトの長さよりもかなり短く (約1.98 ± 0.02 Å). 2.22 Å) である.
- 平均Fe2+) 調整数は,結晶型ファヤライトの6から,液体型ファヤライトの4に減少する.
- この調整の変化は,いくつかのイオン塩の融解による変化に類似しています.
結論:
- オリヴィン組成の溶融物におけるFe(2+) の中距離構造環境のモデルが,観測された協調性の低下に基づいて開発されました.
- この発見は,密度,粘度,Fe-Ni分割を含むFe(2) SiO(4) 液体の主要な性質を説明しています.
- このモデルは,地球の地殻とマントルのシリケート溶解を理解するための意味を持つ.
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