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Paleoproterozoic geodynamics: the Mineiro belt and the Minas orogeny as paradigms

Grant number: 20/08001-0
Support type:Regular Research Grants
Duration: September 01, 2021 - August 31, 2023
Field of knowledge:Physical Sciences and Mathematics - Geosciences - Geology
Principal researcher:Wilson Teixeira
Grantee:Wilson Teixeira
Home Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Assoc. researchers: Ciro Alexandre Ávila ; Danilo Barbuena ; Elson Paiva de Oliveira ; Everton Marques Bongiolo ; Farid Chemale Junior ; Hugo Souza Moreira ; Ivo Antonio Dussin ; Luís Antônio Rosa Seixas ; Matheus Henrique Kuchenbecker Do Amaral ; Mauricio Rigoni Baldim ; Miguel Angelo Stipp Basei ; Natali da Silva Barbosa ; Peng PENG ; Stefano Albino Zincone

Abstract

The Tectono-magmatic Lull has been proposed for a time interval (2.3-2.2 Ga), assuming that continental magmatism (plume and arc magmatism) and orogenic activity significantly decreased at a global scale. The Paleoproterozoic dynamics combine periods of active and quiescent geologic processes that are recorded worldwide. However, there is a polarization of views concerning whether the production of juvenile continental crust has been continuous or episodic throughout the Proterozoic time. Besides, it remains unclear if such records can be a reflex either to sampling bias in the global geologic database or to fundamental changes in geodynamic processes, for instance as a response of the onset of subduction-driven plate tectonics. The Minas accretionary orogeny (2.47-2.03 Ga) that eventually built the São Francisco-Congo paleocontinent produced the Mineiro belt which is the main focus of the project. This belt is a natural laboratory for the understanding of Paleoproterozoic evolution because it contains rare occurrences of juvenile arc-type rocks (Siderian and Rhyacian in age) and because of the composition of the granitoids that vary through time and space. The new and compiled data and geologic correlations will test the hypothesis of a bulk juvenile-type Paleoproterozoic landmass in the South American continent, during the Tectonic-magmatic Lull. The project addresses the role of Mineiro belt and the Minas orogen with roughly coeval accretionary orogens worldwide in the context of the Columbia Supercontinent. A multi-disciplinary approach of techniques (e.g., precise U-Pb geochronology in zircon, combined zircon Hf and O constraints, isotopic and geochemical evidence) will be applied during 24 months planned for this project. The integrated results will be interpreted by a multi-institutional research team toward a better understanding of the Earth lithosphere and plate dynamics as paradigms. (AU)