U-Pb, Lu-Hf, and REE ZIRCON DATA FROM MAGMATIC ZIRCON IN DEVONIAN - CARBONIFEROUS GRANITES AS MONITORS OF CRUSTAL GROWTH AND GEODYNAMIC SETTING, ANDEAN MARGIN OF SW GONDWANA

• Grant number: 24/15338-1
• Support Opportunities: Research Grants - Visiting Researcher Grant - International
• Start date: May 01, 2025
• End date: July 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Miguel Angelo Stipp Basei
• Grantee: Miguel Angelo Stipp Basei
• Visiting researcher: Juan Andres Dahlquist
• Visiting researcher institution: Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
• 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 continental crust is the primary archive of the Earth's geological history. Furthermore, the continents are where most of us live and where most of the natural resources that we use are stored. The longstanding questions are when the continental crust was generated, and how the processes involved in the generation of the continental crust have changed with time. Combined studies, including whole-rock chemistry, geochronology, and isotope data are designed to answer the questions referred above. In particular, integrated geochronological and isotope studies are relevant to characterizing the magmas involved, the degree of crustal reworking or the formation and stabilization of new continental crust by juvenile material accretion. In particular, the magmas produced in magmatic arcs related to the subduction of the oceanic slab represent immense accumulations of intermediate calc-alkaline igneous rocks, and are considered the main "factories" of continental crust on Earth. For this reason, understanding the development of magmatic arcs systems and their evolution over time has sparked the scientific interest of various researchers, dedicating many years of study to the magmatism produced in these geodynamic settings. In general, the present study is focused on the generation and evolution of the Devonian-Carboniferous continental crust developed on the Andean margin, an archetypical subduction margin. This research contributes significantly to the global understanding of magmatic arc systems and the subsequent building of continental crust. In this project, we focus our studies on Devonian-Carboniferous magmatism because as described in the project, we have an appropriate database developed in previous collaborative work over 12 years (detailed maps, petrological and geochemical studies, geochronology, and isotopic data) to develop and deeper combined studies of U-Pb, Hf, and REE in zircon. New U-Pb, Lu-Hf, and REE data from magmatic zircon are required to achieve the general goal, and this is the main specific goal of the present research project. It is worth mentioning that there is still no REE available in zircon crystals for the Devonian-Carboniferous magmatism to be studied in the proposed research. In addition, if successful, this research will provide a set of igneous zircons from rocks that are quite young compared to the Brazilian Precambrian that will be used for the tests planned during the implementation of the Triple Split System foreseen (FAPESP EMU 2022-11421-PAIP) project, which is in development at CPGeo-IGc-USP. (AU)