地球核心-地幔边界区域的地震平面图和热结构
R D van der Hilst1, M V de Hoop, P Wang
1Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge MA, USA. hilst@mit.edu
概括
这项研究使用地震波分析揭示了地球深层结构,识别了地幔最下层的接口和温度变化. 这些发现提供了对地球的新见解.
科学领域:
- 地质物理学 地质物理学
- 地震学 地震学
- 矿物物理 矿物物理
背景情况:
- 地球的内心深处 (D'') 区域,就在核心-地幔边界上方,在行星动力学中起着至关重要的作用.
- 了解地幔酸盐的热力学特性和相变是解释地震数据的关键.
研究的目的:
- 使用地震波分析,以高分辨率探索地球深部 (D'').
- 为了识别结构接口和估计D'层内的温度.
- 研究矿到矿后阶段过渡及其影响.
主要方法:
- 采用了核心反射的剪切波的三维反射散射.
- 分析地震波速度,绘制结构边界图.
- 利用地幔酸盐的热力学特性来解释地震图像和估计温度.
主要成果:
- 在中美洲和北美洲下方的D'层中检测到多个连续的接口.
- 观察到广泛的波速增加与矿过渡到后矿过渡相一致.
- 估计核心-地幔边界温度为3950 +/- 200 K,并在中美洲下方确定了一个寒冷的D'区域.
结论:
- 内部D'分层表明多个相位边界的跨越.
- 深度波速降低可能表明一个后矿透镜.
- 估计的核心热量流在35至160mW m(-2之间,这表明全球平均值为50至100mW m(-2).
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