Paleogeography and the Earth's magnetic field paleointensity in the Neoarchean: A paleomagnetic study of the Parauapebas and Igarapé Bahia Formations (Carajás)

• Grant number: 21/11126-1
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2022
• End date: April 30, 2024
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geophysics
• Principal Investigator: Ricardo Ivan Ferreira da Trindade
• Grantee: Pedro Luiz Gomes Martins
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 16/06114-6 - The Neoproterozoic Earth System and the rise of biological complexity, AP.TEM

Abstract

The onset of modern plate tectonics, involving subduction and mountain uplift, is a key event triggering the emergence of large continental masses and an oxygen-rich atmosphere, setting the stage for the origin of complex life. But when and how plate tectonics started is still unknown owing partially to the inherent difficulty in studying events that occurred in deep time. The paleomagnetic and paleointensity record have the potential to serve as a key indicator of early Earth deep processes, such as the initiation of plate tectonics, the geodynamo functioning, and the core differentiation. The research project focuses on the paleomagnetic record of an Archean block in the Amazonian Craton, the Carajás Province, for the ~2.76-2.74 Ga interval, when extensive volcanism, dominantly mafic, covered an area of approximately 18,000 km2. In that sense, the main goals of the project are: (i) to provide robust paleogeographic constraints for the Carajás block, yielding a paleolatitude estimate for the block; (ii) to constrain the velocity of the block in the Archean time; and (iii) to obtain a full-vector geomagnetic record for the Carajás region. To fulfill these purposes, petrographic, paleomagnetic, and zircon U-Pb geochronology studies will be developed, for the least altered volcanic rocks inserted in the Neoarchean volcano-sedimentary sequence of the Grão-Pará Group.