Mesoarchean to Orosirian evolution of the Piedade Microcontinent, SE Brazil: crustal growth, continental arc magmatism and successor basin development

Archean crustal fragments preserved within Paleoproterozoic orogenic belts provide important records of crustal growth, recycling and continental assembly. In the southern Minas-Bahia Orogenic System (SE-Brazil), the tectonic evolution of several Archean blocks and the Paleoproterozoic arc systems remains poorly constrained. One of these Archean domains is the Piedade Microcontinent, located between the Mineiro Belt and the Mantiqueira-Juiz de Fora Magmatic Arc System. This study integrates geological mapping, whole-rock geochemistry and Sm-Nd-Sr isotopes, and zircon U-Pb and Lu-Hf data to investigate its tectono-magmatic evolution and associated metavolcano-sedimentary sequences. The Archean basement records crustal growth between ca. 3.24 and 2.52 Ga and is characterized by predominantly juvenile isotopic signatures. Along the northwestern margin of the microcontinent, a previously unrecognized continental arc, herein named the Ressaquinha magmatic arc, developed between ca. 2.14 and 2.08 Ga. Geochemical and isotopic data indicate extensive reworking of older continental crust during arc magmatism. Collision between adjacent terranes occurred between ca. 2.08 and 2.05 Ga and was followed by late- to post-collisional bimodal magmatism represented by the São Bento dos Torres post-collisional suite. Detrital zircon data from metasedimentary rocks of the Barbacena metavolcano-sedimentary sequence yield maximum depositional ages between ca. 2.08 and 2.02 Ga and reveal contributions from the Archean basement, the Ressaquinha magmatic arc, the São Bento dos Torres post-collisional suite and juvenile adjacent terranes ( i.e. , Mineiro Belt and Mantiqueira-Juiz de Fora Magmatic Arc System). Together with the occurrence of associated mafic, alkaline and metaultramafic rocks, these data suggest that sedimentation began during the final stages of arc evolution and continued within a successor basin after final terrane amalgamation. These results redefine the northern limit of the Piedade Microcontinent, document a newly identified Paleoproterozoic continental arc and constrain the transition from arc magmatism to post-collisional basin development during assembly of the southern São Francisco Paleocontinent.