潮断层扫描限制了地球的深层浮力
Harriet C P Lau1, Jerry X Mitrovica1, James L Davis2
1Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA.
Nature
|November 17, 2017
概括
地球的固体地球潮流显示,非洲和太平洋下面的大低剪速区域 (LLSVPs) 的密度比以前想象的要高. 这表明它们的浮力由高密度的化学成分主导,
科学领域:
- 地质学
- 地球科学
- 地震学
背景情况:
- 身体的潮,或固体的地球潮,是由于月球和太阳的引力,地球表面的移动.
- 大型低剪速区域 (LLSVPs) 是核心-地幔边界的大型结构,其浮力受到争议.
- 了解LLSVP密度对于地幔动态和地球演变至关重要.
研究的目的:
- 通过体潮变形来限制LLSVP的深层浮力.
- 调查非洲和太平洋LLSVP中的密度异常.
主要方法:
- 使用潮断层扫描, 分析半日体潮变形.
- 使用全球定位系统 (GPS) 测量精确的表面位移数据.
- 应用概率方法来分析密度变化.
主要成果:
- 显示低三分之二的LLSVP的平均密度大约比周围地幔高0.5%.
- 表明这种密度异常可能集中在地幔的底部.
- 将LLSVP的平均浮力限制在0.5%左右.
结论:
- 低密度聚烯的浮力主要是由高密度化学成分的丰富驱动的.
- 海洋板块或原始物质可能是这些密集成分的来源.
- LLSVP的密度结构对地幔对流,LLSVP的稳定性和地球系统的长期演变具有重要意义.
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