New paleodirectional and paleointensity data to assess the effects of the South Atlantic Anomaly over the last 10 million years

• Grant number: 24/22481-5
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: March 03, 2025
• End date: August 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geophysics
• Principal Investigator: Gelvam André Hartmann
• Grantee: Sebastian Camilo Aguilar Moncada
• Supervisor: Andrew John Biggin
• Host Institution: Instituto de Geociências (IG). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: University of Liverpool, England
• Associated to the scholarship: 24/01985-5 - Paleomagnetic field evolution for the last 10 Ma, BP.MS

Abstract

Earth's magnetic field (EMF) of internal origin exhibits variations across different time scales, ranging from years to billions of years. An integrated analysis of paleodirection and paleointensity data for the last 10 Ma reveals non-dipolar field features that appear similar to those observed in field models and data for time scales of centuries to millennia. The main non-dipole field feature is the South Atlantic Magnetic Anomaly (SAA), which is characterized by the lowest total field intensities at the Earth's surface. However, the structure of the EMF is largely constrained by the quality and spatial and temporal distributions of paleomagnetic data. The scarcity of these data is particularly evident at low and high latitudes in both hemispheres, especially in the Southern Hemisphere. The main objective of this research project is to study the variation of the EMF for the time interval of 0-10 Ma, based on a selection of available paleomagnetic data from the literature, combined with a new set of paleodirection and paleointensity data that will be obtained from volcanic rocks in the Andes Mountains in Argentina. Based on these data, the project aims to: (i) evaluate the behaviour of the paleosecular variation (PSV) by analysing the angular dispersion of a distribution of virtual geomagnetic poles as a function of latitude and geomagnetic reversal frequency; (ii) contribute with new paleointensity data to understand the influence of SAA on these timescales Paledirectional data were already obtained from volcanics of Auca Mahuida volcanic field and will be evaluated through PSV analysis. Absolute paleointensity measurements will be determined using the microwave method, which is available only at the Geomagnetism Laboratory of the University of Liverpool (UK), in collaboration with and under the guidance of Prof. Andrew Biggin. The analyses of PSV and the new paleointensity data will be conducted using the procedures and standards developed by the Geomagnetism Laboratory group. This new set of data (paleointensity and paleodirectional) and their evaluations will provide insights into the variability of the geomagnetic field on timescales of a few million years.