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

• Applicant: Privatdozent Dr. Florian Lhuillier
• Subject Area: Geophysics
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 272370511

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.

• DFG Programme: Research Grants
• Co-Investigators: Professor Dr. Stuart Alan Gilder; Professor Dr. Nikolai Petersen