Chronology of accretionary processes in the vicinity of the Santa Quitéria magmatic arc - NW Borborema Province

• Grant number: 23/15595-1
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2024
• End date: January 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Ticiano José Saraiva dos Santos
• Grantee: Ticiano José Saraiva dos Santos
• Host Institution: Instituto de Geociências (IG). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated researchers: ALANIELSON DA CAMARA DANTAS FERREIRA ; David Jozef Cornelius Debruyne ; Elton Luiz Dantas ; Jeffrey David Vervoort ; João Paulo Araújo Pitombeira ; Wagner da Silva Amaral

Abstract

The formation of mountain ranges arises from the destruction of oceanic lithosphere in subduction zones, followed by the formation of magmatic arcs and culminating in the collision of continental masses generated in different tectonic environments. Several studies conducted in the NW of the Borborema Province have revealed advances and challenges in understanding the tectonic evolution of the Ceará Central Domain. The evolution of the eclogite belt (HP-UHP) on the eastern margin of the Santa Quitéria Magmatic Arc (AMSQ) plays a key role in the Neoproterozoic subduction system. Consequently, the primary goal of this project is to enhance our understanding of the HP-UHP rocks adjacent to the AMSQ and their eastward extension, with a specific focus on the evolutionary processes of these HP-UHP rocks. Field studies highlight a strong spatial association between eclogitic rocks (HP-UHP) and metacarbonates. In this context, examining lithium isotopes (´7Li) in metabasic rocks, metasedimentary host rocks, and marbles can provide valuable insights into the regional polyphasic metamorphism. This approach enables the assessment of the mechanism and duration of the exhumation process of retroeclogites along the margins of the AMSQ, and directly relates to the P-T trajectories. The P-T conditions in the mineral assemblages present in these rocks will be precisely determined by combining the application of consolidated geothermometers and geobarometers with pseudosection modelling. U-Pb SHRIMP and LA-ICP-MS dating on zircon, monazite, titanite, and rutile will define the crystallization and metamorphic ages of metabasic rocks. These data will be complemented with Lu-Hf analyses on zircon and garnet, serving as a powerful tool for understanding the geological history of these terrains. Through the detailed study of HP-UHP rocks, the project aims to establish a consistent tectonic model for the subduction system in the Ceará Central Domain and its integration into the evolution of West Gondwana. (AU)