New Archean and Statherian magmatic records within the Guanhães basement inlier (Araçuaí Orogen, Brazil)

The Guanhães basement inlier, a segment of the São Francisco–Congo Paleocontinent reworked within the Neoproterozoic Araçuaí Orogen, hosts granitic plutons that have been assigned in regional geological maps, mainly on the basis of field relationships, to possible Rhyacian/Orosirian units. Such an assignment would imply a potential connection with the Minas–Bahia Orogeny, the event responsible for the amalgamation of the São Francisco–Congo Paleocontinent. Given the relevance of ancient basement records for reconstructing the evolution of this paleocontinent, we conducted petrographic, whole-rock geochemical and U–Pb geochronological investigations to constrain the genesis of two of these candidate units: the Dom Joaquim Pluton (DJP) and the Jenipapo Granite (JG). The DJP consists of high-K calc-alkalic, magnesian, peraluminous muscovite–biotite metagranites, with a crystallization age of 2699 ± 10 Ma, inherited zircon components at ca. 2.9 Ga, and metamorphic overprinting at 508 ± 13 Ma. These rocks show close affinities with other ca. 2.7 Ga granitoid occurrences described in the Guanhães basement inlier. We therefore define the Dom Joaquim Suite to encompass the DJP and related Neoarchean granitoids in the region. The new data reveal that rocks previously mapped under the JG designation comprise two distinct groups: (i) alkali-calcic, ferroan, metaluminous biotite metagranites that record a magmatic event at 2910 ± 13 Ma, with inherited zircon components at ca. 3.0 Ga and metamorphic overprinting at ca. 2.7 Ga and ca. 540 Ma; and (ii) A-type, calc-alkalic, ferroan, metaluminous hornblende–biotite metagranites with a crystallization age of 1799 ± 34 Ma. The biotite metagranites show strong similarities to the Amaros Pluton, which records Mesoarchean crustal melting in the Guanhães basement inlier. To organize the regional Archean magmatic record, we define the Amaros Suite to encompass the Amaros Pluton and related Mesoarchean granitoids of the Guanhães basement inlier. In contrast, the hornblende–biotite metagranites are interpreted as part of the Borrachudos Suite, recording the transition to intracratonic extensional regimes within the São Francisco–Congo Paleocontinent during the Statherian. Together with available regional datasets, our results indicate a polycyclic Archean crustal evolution in the Guanhães basement inlier, involving the formation of TTG crust between ca. 3.2 and 3.0 Ga, followed by episodes of crustal reworking during the Mesoarchean and Neoarchean. These evolutionary stages resemble those recorded in the southern São Francisco Craton, suggesting that these domains may have belonged to a continuous crustal segment prior to the Minas–Bahia Orogeny. • New data reveal Archean–Statherian magmatism in the Guanhães basement inlier, Araçuaí Orogen, Brazil. • Archean suites record Meso- and Neoarchean crustal reworking. • Statherian magmatism reflects intracratonic anorogenic activity during Espinhaço rifting. • Polycyclic Archean evolution and links to the southern São Francisco Craton are indicated.