Zircon and the evolution of cratons: study case: Amazonian Craton and its counterparts in Western Gondwana

• Grant number: 20/04625-9
• Support Opportunities: Research Grants - Visiting Researcher Grant - Brazil
• Start date: October 01, 2020
• End date: September 30, 2021
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Colombo Celso Gaeta Tassinari
• Grantee: Colombo Celso Gaeta Tassinari
• Visiting researcher: Moacir Jose Buenano Macambira
• Visiting researcher institution: Universidade Federal do Pará (UFPa). Instituto de Geociências, Brazil
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 15/03737-0 - The Rio de La Plata Craton and the Western Gondwana Assembly, AP.TEM

Abstract

The Amazonian craton has an area equivalent to half of the country's surface and represents the least known region of the South American continent in terms of geological context. For the rational exploration of the mineral resources with sustainability, it is necessary to know the constitution of its terraines, as well as the understanding of their formation and evolution. Regarding the first aspect, geological mapping is a process that has been developing quite irregularly. In addition, due to the large area and the difficulty of access caused by the dense forest, reduced number of roads and the intense alteration of the outcrops, the necessary investments become more voluminous than those applied in other brazilian regions . On the other hand, the models for the continental crust evolution of the Amazonian craton have advanced a lot thanks to a continuous investment in isotopic geology carried out by institutions and research groups, which has generated a collection of significant geochronological and geochemical data supported by the available classical geological information. So that the proposed models for the characterization of the geochronological provinces of the Amazonian Craton and their respective tectonic evolution, despite the differences in denomination, concept and geographic distribution, come close to a consensus. The main objective of this research is to test these models in key áreas to eliminate doubts confronting informations to improve the existing models of crustal evolution, substantiating them with new isotopic data, obtained by advanced and sophisticated methods of investigation.The theme covered by this project has been developed by the researchers involved in this proposal, as Responsible and Visitor, for some decades. In this plan, the objective is to better understand the tectonic evolution of the Amazonian craton, especially the central-eastern and northern parts, and its comparison with the West African and Angola cratons in their geochronological and tectonic aspects. Such regions have lithological units that are important markers of changes in the formation of the continental crust, in the tectonic regime and, as well as, in the products generated during the geological time. The project will also contribute to the study of the metallogenetic processes related to the formation of hydrothermal ore deposits during the Archean and Paleoproterozoic, through the application of geochronological methods and isotopic geochemistry, with the use of advanced techniques applied to zircon grains. The geological interpretations of these data will be integrated with the previous geological informations obtained by claasical methods.The analytical work will be carried out at Geochronological Research Center (CPGeo) of the Institute of Geoscience of the University of São Paulo, which has the largest analytical park of isotopic analysis in the country, and the Project will have the Isotopic Geology Laboratory of the Federal University as an adjunct. from Pará, whose responsible research group is led by the Visiting Researcher. In this context, it is intended to apply, implant and / or develop isotopic and mineral chemistry methodologies applied in zircon crystals, such as U-Pb, Lu-Hf, Sm-Nd, ETR and Ti, testing their potential and determining their limitations. (AU)