Constraining the evolution and deformation timescales in the Ediacaran Itajaí Foreland Basin using white mica in-situ Rb-Sr geochronology

• Grant number: 25/01257-2
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: June 01, 2025
• End date: November 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Miguel Angelo Stipp Basei
• Grantee: Rafael Moreti Arantes Vieira
• Supervisor: Bruno Vieira Ribeiro
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Curtin University, Australia
• Associated to the scholarship: 21/11048-0 - Investigating and quantifying deformation across the Itajaí foreland basin, Southern Brazil, BP.DD

Abstract

During the Ediacaran period, foreland basins likely played a crucial role in the evolution of macroscopic life by enhancing nutrient availability through sediment accumulation derived from the erosion of Neoproterozoic mountain belts, capturing complex interactions between large-scale tectonic forces, shallow crustal dynamics, climate, and denudation. Understanding the kinematics and timescales of foreland basin evolution is challenging due to structural complexities arising from late- to post-sedimentary deformation and far-field tectonic forces, requiring detailed structural studies to reconstruct the basin in its undeformed state. Recent advancements in in-situ Rb-Sr geochronology of white mica provide a novel method for dating texturally controlled and detrital white mica, which aids in the interpretation of provenance and thermal events influencing foreland basins. The in-situ Rb-Sr dating method will be applied to white mica in various samples from the Dom Feliciano Belt (DFB) foreland basin, including deformed or not siltstones, sandstones and tuffs, to establish a chronological framework for its evolution. The project objective is to determine precise ages associated with recrystallization textures, sedimentary features, cleavage, deformed zones and detrital white mica. By combining Rb-Sr dating of recrystallized minerals and detrital white mica analysis, the study addresses challenges in interpreting low-temperature geochronology and distinguishing sedimentary, detrital, and deformation-related textures. The Itajaí Basin, located on the northern foreland of the DFB, displays a variety of structural styles in terms of faulting and folding geometries, and this study aims to establish the chronology of shallow crustal tectonics during the development and deformation of the foreland basin, contributing to the understanding of basin evolution timescales. The findings will provide insights into sedimentary provenance, deformation timing, and tectonic influences on the foreland basin, supporting structural reconstructions, and by integrating structural geometries, deformation styles, mineral textures, and fault kinematics. This work will enhance knowledge of tectonic evolution in West Gondwana's collisional orogens during the Ediacaran.