まとめ
この研究では,アンソフィライトにおけるFe2+) -Mgの秩序-乱動力学を定量化しています. これは,鉱物の均衡温度に基づいて,最大岩の冷却速度が 1 x 10 (−4) °C/年であることを示しています.
科学分野:
- ミネラロジーは,鉱物学です.
- 地質化学 地質化学
- 熱力学は熱力学である.
背景:
- 鉱物におけるFe2+) -Mgの秩序-乱雑現象は,地質学的過程を理解するために極めて重要です.
- 複雑なアンフィボールであるアンソフィライトは,この現象を示し,熱の歴史を記録しています.
研究 の 目的:
- 自然のアントフィライトにおけるFe(2+) -Mgの秩序-乱雑反応の運動を決定する.
- この結晶内交換を制御する熱力学的パラメータを確立するために.
- 鉱物均衡に基づいて宿主岩の最大冷却速度を計算する.
主な方法:
- 2 kbarの温度で400~720°Cの温度範囲でアンソフィライトにおけるFe(2+) -Mg交換の運動学的研究.
- オーダーリング/ディソードリング反応のギブス自由エネルギーとアクティベーションエネルギーの計算.
- 反応動力学に基づいて鉱物の均衡温度を決定する.
主要な成果:
- 均衡は,600°C以上で秩序と混乱の両方を通じて達成されます.
- 結晶内交換のための標準ギブス自由エネルギーは4247 ± 54cal/f.u.です.
- 交換反応の活性化エネルギーは,約55 kcal/f.u. になります.
- 天然アンソフィライトの均衡温度が270°Cであった.
結論:
- この研究は,アンソフィライトにおけるFe2+) -Mg配列の定量運動データを提供します.
- 判定された270°Cの均衡温度は,宿主岩の最大線形冷却速度が1×10~4) °C/年であることを意味する.
- これらの発見は,急速な冷却イベントのためのジオクロノメーターとしてアンソフィライトの使用を強化します.
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