The Nico Pérez Terrane (Uruguay): an exotic basement block of Western Gondwana? Comparison with Curitiba and Luiz Alves microplates (south Brazil)

• Grant number: 13/09010-9
• Support Opportunities: Research Grants - Visiting Researcher Grant - International
• Start date: August 25, 2013
• End date: November 24, 2013
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Miguel Angelo Stipp Basei
• Grantee: Miguel Angelo Stipp Basei
• Visiting researcher: Siegfried Siegesmund
• Visiting researcher institution: Göttingen University, Germany
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 08/57861-0 - National Institute for the Development of Advanced Geochemical Analytical Procedures Applied to Oil and Gas Exploration, AP.TEM

Abstract

The break-up of Rhodinia at about 800 Ma is the start point of the amalgamation of southwestern Gondwana. Convergence of major Kalahari, Congo and Río de la Plata cratons and cratonic fragments as Luis Alves and Curitiba Microplates resulted in the Neoproterozoic to Cambrian Dom Feliciano- Kaoko-Damara-Gariep orogenic belts. Several geodynamic scenarios for western Gondwana assembly have been proposed and in all models the Rio de la Plata Craton is of significant importance. In western Uruguay the Río de la Plata Craton is composed of two main terranes: the Piedra Alta Terrane (PAT) on the western side of the Sarandí del Yí Shear Zone (SYSZ) and the Nico Pérez Terrane (NPT) on the eastern side of this lineament. The Nico Perez terrane, main target of this project, evidences a complex evolution with magmatic crystallization ages ranging from Archean to Mesoproterozoic. The proposed visit intents to address the following major questions regarding the tectonic mean of Nico Perez Terrane: 1)-Since when was the Rio de la Plata Craton involved in this multistage accretion process?, 2)- What is the tectonic meaning of the Nico Pérez Terrane?, 3)-What is the significance of the Sarandí del Yí Shear Zone? and 4)- can NPT and Luiz Alves/Curitiba microplates be correlated? To address these questions the isotopic signature of the NPT (to be improved in this project) will be compared with the available U-Pb and Hf data of Piedra Alta Terrane and Luiz Alves/Curitiba domains. It is expected that this research contributes to solve the problems involved in the correlation of the basement domains observed in south Brazil and Uruguay, resulting on improved models of the genesis of West Gondwana. (AU)