Improvement of archeomagnetic modeling techniques for South America by implementing new Bayesian regularizations and the Equivalent Source Dipole (ESD) approximation

• Grant number: 25/00343-2
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: March 25, 2025
• End date: January 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geophysics
• Principal Investigator: Gelvam André Hartmann
• Grantee: Victor Jorge de Oliveira Marum
• Supervisor: Hagay Amit
• Host Institution: Instituto de Geociências (IG). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Université de Nantes, France
• Associated to the scholarship: 23/02667-4 - Archeomagnetic field modelling for the last few millennia in South America, BP.DR

Abstract

The Earth's magnetic field (EMF) undergoes significant variations on timescales ranging from milliseconds to millions of years, driven by internal geodynamo processes and external solar influences. A prominent feature of the EMF, the South Atlantic Magnetic Anomaly (SAA), is characterized by a minimum in geomagnetic field intensity and is related to anomalies in Earth's outer core, driven by non-dipole field components. Despite its impact on technological systems and biological processes, the spatial and temporal evolution of the SAA remains poorly understood, especially in South America due to the scarcity of data. This proposal aims to develop a comprehensive and robust regional model of the geomagnetic field for South America over the last 5 millennia. An integrated database comprising archeomagnetic, volcanic and sedimentary data, focusing on strict data selection criteria will be proposed. A new regional model for South America will be developed, offering insights into the SAA's evolution and its association with core dynamics, particularly through applying the Equivalent Source Dipole (ESD) approach. This method should be effective for small-scale and rapidly changing magnetic fields and could enhance our understanding of secular variation (SV) and the geodynamo dynamics. Results from this research will improve the geomagnetic field reconstructions, better tracking of the SAA and offer significant advancements in the study of geomagnetic anomalies. The steps described in this proposal are expected to be carried out at the Laboratoire de Planétologie et Géosciences (LPG) at the University of Nantes, France, under the supervision of Prof. Hagay Amit, in collaboration with Dr. Filipe Terra-Nova.