在太平洋中部下面的矿后透镜和D'热流
Thorne Lay1, John Hernlund, Edward J Garnero
1Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064, USA. thorne@pmc.ucsc.edu
概括
地震数据显示了地球D'区域的温度梯度,这表明矿矿物质因铁缩而发生相位变化. 这为下层地幔的热结构和热流提供了新的见解.
科学领域:
- 地质物理学 地质物理学
- 矿物物理 矿物物理
- 地震学 地震学
背景情况:
- D'区域是地球上最低的地幔,呈现出复杂的地震结构.
- 了解其热和化学特性对于地幔动力学至关重要.
研究的目的:
- 在太平洋中部下方的D'区域推断温度梯度.
- 研究矿物相变在地震不连续性中的作用.
主要方法:
- 对S波速度变化的分析.
- 解释地震不连续性作为矿物阶段过渡 (矿石到后矿石,反过来).
主要成果:
- 观测到快速的S波速度增加,随后下降,表明配对的地震不连续.
- 将这些不连续性归因于矿-矿后-矿-矿相位变化由温度驱动.
- 预计区域核心-地幔边界热量流量为85 +/- 25 mW/m2,全球热量流量下界为13 +/- 4 TW.
- 佩洛夫斯基特后矿物质透镜由于温度升高约500K而侧面变薄.
结论:
- 该研究使用双相边界交叉限制了地幔最下层的温度梯度.
- 铁丰富被提议解释矿后的稳定性在该地区较浅的深度.
- 提供核心-地幔边界热量流和全球热量流的估计.
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