理论和实验证据表明,MgSiO3在地球D"层中的矿石后阶段存在
1Laboratory of Crystallography, Department of Materials, ETH Zurich, Wolfgang Pauli Strasse 10, CH-8093 Zurich, Switzerland. a.oganov@mat.ethz.ch
Nature
|July 23, 2004
概括
地球下层地幔中的酸矿在D"层条件下转化为矿后的矿阶段. 这一新阶段解释了在最下层地幔中观察到的令人费解的地震特性.
科学领域:
- 地质物理学 地质物理学
- 矿物物理 矿物物理
- 计算材料科学科学 计算材料科学
背景情况:
- 地球下层地幔的矿物学,主要是 (Mg,Fe) SiO3矿,无法解释D"层的异常性质.
- D"层,地幔的最下层约150公里,表现出独特的地震特征.
研究的目的:
- 为了研究与D"层相关的MgSiO3的高压,高温行为.
- 确定一种矿物阶段,可以解释D"层所观察到的地震特性.
主要方法:
- 使用ab initio模拟来模拟极端条件下的材料行为.
- 进行高压实验以验证理论预测.
主要成果:
- 在D"层压力和温度下,MgSiO3从矿过渡到CaIrO3类型的矿后结构.
- 矿后阶段计算的弹性特性与D"层的地震观测结果一致.
结论:
- MgSiO3 的矿石后阶段是 D" 层中占主导地位的矿物.
- 这种相位过渡解释了地震异构性和D"层顶部的剪切波不连续性.
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