Constraints on the Statherian tectonic evolution of the São Francisco paleocontinent: the Espinhaço Basin and the Guanhães Crustal Core Complex

This study integrates U–Pb zircon geochronology and Lu–Hf isotope data from metasedimentary rocks of the Southern Guanhães Basement Inlier and surroundings with detailed mapping and structural analysis to propose a refined geodynamic model for the São Francisco paleocontinent during the Statherian period, highlighting the interplay between the Espinhaço Basin sedimentation and the contemporaneous exhumation of the anorogenic Borrachudos Suite. The detrital zircon age spectra of the analyzed samples exhibit distinct clusters at Archean (3500–2500 Ma), Neoarchean–Siderian (2500–2400 Ma), Rhyacian–Orosirian (2300–1915 Ma), and Statherian (1800–1675 Ma), with a well-constrained maximum depositional age (MDA) of 1727 ± 7 Ma. The subchondritic εHf(t) signatures (−18.0 to −13.0) of the Statherian zircon grains unequivocally identify the anorogenic granites of the Borrachudos Suite as the youngest source of detritus for the Lower Espinhaço Sequence within the Southern Guanhães Basement Inlier. The comparison of relative age probability between the Lower Espinhaço Sequence in the Southern Espinhaço Range (its typical location) and the analyzed metasedimentary rocks reveals a significantly higher contribution from Statherian sources within the Guanhães Basement Inlier. ... mehrThe common sedimentary source of these units, combined with the distribution of normal-sense displacement faults and shear zones reactivated and aligned with the regional shear zones, whose present kinematics converge towards and enclose the area of exposure of the Borrachudos Suite, supports the interpretation that the deep plutonic rocks of the Borrachudos Suite were exhumed and eroded together with the Archean basement during the formation of the Espinhaço rift basin. This tectonic scenario resulted in the juxtaposition of sediments of the Lower Espinhaço Sequence, which were deposited between uplifted crustal blocks during the Statherian, here collectively referred to as the Guanhães Crustal Core Complex.