Understanding 30 Myr of geomagnetic field variability: a case study from low latitude (Ethiopia)

了解 30 马里尔的地磁场变化：低纬度地区的案例研究（埃塞俄比亚）

• 批准号: 272370511
• 负责人: Privatdozent Dr. Florian Lhuillier
• 金额: --
• 依托单位: Sektion Geophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/272370511?language=en
• 关键词: Understanding; 30; Myr; geomagnetic; field

How the Earth's magnetic field varies over time, called secular variation, lends insight into the workings of the geodynamo. However, it remains debated which measurable quantities and the timescales over which they should be observed, are required to obtain a complete description of secular variation. Our numerical study of five dynamo models suggests that at least a half million years of time with 100 time-independent directional and intensity data are needed to distinguish different dynamo regimes. We now wish to test these theoretical predictions by sampling four thick (1000-2500 m) sections of volcanic flows in Ethiopia that were emplaced over the past 30 Myr. We aim to discern whether secular variation evolved during this period by investigating the geometry and dispersion of directions as well as the magnitude and dispersion of field intensity. Ethiopia is specifically chosen due to the large number of flows (>100) at each section, their accessibility, and their significant time span at a relatively constant geographic locality. Work in Ethiopia will be facilitated with a long-term collaborator, Professor Tesfaye Kidane.

地球磁场如何随时间变化，称为长期变化，有助于了解地球发电机的工作原理。然而，它仍然是有争议的可测量的数量和时间尺度，他们应该被观察到，需要获得一个完整的描述长期变化。我们对五个发电机模型的数值研究表明，至少需要50万年的时间和100个与时间无关的方向和强度数据来区分不同的发电机制度。我们现在希望通过对埃塞俄比亚过去3000万年来形成的四个厚（1000-2500 m）火山流部分进行采样来测试这些理论预测。我们的目标是辨别是否长期变化在此期间通过调查的几何形状和分散的方向，以及场强的大小和分散的演变。特别选择埃塞俄比亚是因为每个路段的流量很大（>100），它们的可达性，以及它们在相对恒定的地理位置上的显著时间跨度。在埃塞俄比亚的工作将得到长期合作者Tesfaye Kidane教授的协助。

项目成果

Palaeointensities of Oligocene and Miocene volcanic sections from Ethiopia: field behaviour during the Cainozoic

• DOI: 10.1093/gji/ggy491
• 发表时间: 2019-02
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: F. Lhuillier;V. Shcherbakov;V. Shcherbakova;S. Ostner;G. Hervé;N. Petersen

Impact of inner-core size on the dipole field behaviour of numerical dynamo simulations

• DOI: 10.1093/gji/ggz146
• 发表时间: 2019-07-01
• 期刊: GEOPHYSICAL JOURNAL INTERNATIONAL
• 影响因子: 2.8
• 作者: Lhuillier, Florian;Hulot, Gauthier;Schwaiger, Tobias
• 通讯作者: Schwaiger, Tobias

Palaeomagnetism and geochronology of Oligocene and Miocene volcanic sections from Ethiopia: geomagnetic variability in the Afro-Arabian region over the past 30 Ma

埃塞俄比亚渐新世和中新世火山剖面的古地磁学和地质年代学：过去 30 Ma 非洲-阿拉伯地区的地磁变化

• DOI: 10.1093/gji/ggy517
• 发表时间: 2019
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: Lhuillier;S. A. Gilder
• 通讯作者: S. A. Gilder