Thermo-kinematic evolution of the Anta Gorda anticlinorium basement and metasedimentary cover, southern Ribeira Belt

• Grant number: 17/02769-0
• Support type: Scholarships in Brazil - Master
• Effective date (Start): December 01, 2017
• Effective date (End): November 30, 2019
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Principal Investigator: Frederico Meira Faleiros
• Grantee: Maria Thereza Akemi Guimarães Yogi
• Home Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 18/22959-1 - Petrochronological approach for constraining P-T-D-t paths in mylonitic metapelites from Votuverava Group, BE.EP.MS

Abstract

The Anta Gorda Anticlinorium is located in the Apiaí Terrain (Southern Ribeira Belt), comprising Statherian mylonitic orthogneisses (Núcleo Tigre) and a Calymmian metasedimentary rocks association (Votuverava Group). The metamorphism recorded in the Votuverava Group metapelites range from biotite to kyanite zone. A low-angle shear zone is responsible for intense mylonitization, that affects the basement and the metasedimentary rocks. The metamorphic zonation in the metapelitic rocks is strongly controlled by their composition and is associated to the mylonitization event. Besides that, there is a possibility that the shear zone was reactivated in a late deformation phase or during exhumation. Characterizing the deformation through different deformation mechanisms, quartz c-axis fabrics and vorticity analysis is an important key to complement the evolutive history of the area. The main aim of this project is to propose a thermo-kinematic evolution of the Anta Gorda Anticlinorium through the correlation between metamorphic and deformation conditions which Núcleo Tigre and Votuvera Group rocks underwent during the shearing event. The aim will be achieved with bibliographic research, field work, structural, petrographic and microstructural analysis, petrologic modelling, and geochronology. (AU)