Constraining the kinematic and the chronological evolution of Itapirapuã Shear Zone through electron backscatter diffraction (EBSD) and in situ mica Rb-Sr geochronology

• Grant number: 25/07592-8
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: August 01, 2025
• End date: August 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Ginaldo Ademar da Cruz Campanha
• Grantee: Arthur Rodrigues da Silva
• 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: 24/15682-4 - Geometry, deformation and thermokinematic history of Itapirapuã Shear zone, Ribeira belt, Brazil, BP.IC

Abstract

Understanding the kinematics and deformation timing of ductile shear zones is essential for reconstructing the temporal evolution of metamorphic terranes and contributes significantly to tectonic models of continental assembly. Accurately constraining the time evolution of shear zones remains challenging due to the difficulty of determining the exact timing of ductile deformation (mylonitization) and related thermal effects. However, new analytical techniques allow microstructural analysis to provide insights into the evolution of major shear zone systems. This internship project focuses detail microstructural characterization via electron backscatter diffraction (EBSD) and in-situ Rb-Sr geochronology on syn-kinematic mica grains. Such techniques are still unavailable in the Brazilian laboratories and universities. The study will targeted mylonitic fabrics associated with the Itapirapuã Shear Zone. The proposed internship will be carried out at Curtin University, under the supervision of Dr Bruno Vieira Ribeiro. Mineral microstructural mapping via EBSD and in-situ mica Rb-Sr geochronology will contribute to understanding the tectonic significance of the Itapirapuã Shear Zone and to future studies of the thermal history of the Southern Ribeira Belt, greatly contributing to the undergoing FAPESP-IC project (process 2024/15682-4). Such internship abroad will enhance the analytical skills and capacitation of Brazilian researchers to support further implementation of such technical routines in the near future with the installation of new triple quadrupole mass spectrometers.