概括
一种新的热量计技术精确地测量了MgSiO中的伊尔梅尼特-矿过渡的度. 这项研究为了解地球地幔提供了关键的热力学数据.
科学领域:
- 地质化学 地质化学
- 矿物物理 矿物物理
- 热力学是一种热力学.
背景情况:
- 了解酸 (MgSiO3) 的相变对于建模地球地幔至关重要.
- 高压,高温热力学数据对于准确的地球物理模型至关重要.
研究的目的:
- 开发一种敏感的微分滴溶液热量计技术,用于分析微小样本.
- 为了确定MgSiO3.3中伊尔梅尼特-洛夫斯基特过渡的度.
- 评估MgSiO3和Mg2SiO4相过渡的热力学,这与地幔组成有关.
主要方法:
- 使用了一种新的微分滴溶液热量计方法.
- 分析了一份5.18毫克的矿样本,该样本是以25 GPa和1873 K.合成的.
- 计算的反应和压力-温度倾斜.
主要成果:
- 在MgSiO3中,伊尔梅尼特-洛夫斯基特过渡的度被确定为110.1±4.1kJ/mol.
- 两种评估的反应 (伊尔梅尼特到矿和斯宾尔到矿+MgO) 都表现出负的压力-温度倾斜.
- -0.005 ± 0.002 GPa/K 对于MgSiO3 (伊尔梅尼特) 至MgSiO3 (矿).
- -0.004 ± 0.002 GPa/K对于Mg2SiO4 (螺旋) 到MgSiO3 (矿) +MgO (酸盐) 的情况.
结论:
- 开发的热量计技术对于小样本分析是有效的.
- 负的P-T斜率表明这些过渡可能会影响地幔动态.
- 螺旋到矿+MgO反应的P-T斜率可能不够负,无法防止整个地幔的对流.
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