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The Mineiro belt occurs along the southern edge of the São Francisco Craton, as part of a large orogen resulted from convergence of Neoarchean fragments, lithosphere shortenning and collision of the accreted Paleoproterozoic terranes. The geodynamics (2.4-1.9Ga) included the formation of passive margin and back arc basins, calc-alkaline and alkaline magmatism (including the extensive Mantiqueira gneissic complex, largely reworked in Neoproterozoic times), greenstone sucessions, and deposits indicating provenance from the foreland/active continental margin/intraoceanic arc settings. Contemporary and associated with the continental growth, collision and extensional collapse of the belt, deformation and metamorphism overprinted the foreland. The pre, syn and late orogenic stages produced several plutonic pulses (2250-2200; 2190-2160; 2130-2040Ma) either by intraoceanic dynamics with minor recycling of material formed in previous accretionary phases, or by partial melting of Archean crust. The oldest plutonism which locates southward of the Lenheiros Shear Zone (LSZ) includes the Serrinha suite composed of plutonic, subvolcanic and volcanic terms (sub-alkaline, calc-alkaline, metaluminous and peraluminous). The Serrinha rocks give U/Pb and 207Pb/206Pb zircon ages between 2239 ± 25Ma and 2207 ± 4Ma. Their TDM ages (2.6-2.3Ga), εNd (t) values (-0.8 to +1.8) and initial 87Sr/86Sr ratios (0.703) suggest the protholiths derived predominantly from Paleoproterozoic juvenile sources, in an intraoceanic arc zone. The plutons located northward of LSZ have distinct U/Pb and 207Pb/206Pbzircon ages (from 2191 ± 9Ma to 2101 ± 8Ma); TDM ages (2.5 to 2.7Ga) and εNd (t) values (-1.3 to -5.1), suggesting Archean components participated as magma source for the protholiths. These intrusions are contemporary with the Mantiqueira gneisses (U-Pb ages of 2180-2160Ma; 2102-2040Ma) whilst representing an inboard magmatism. A few crystallization ages (2203 to 2210Ma) of the Mantiqueira rocks revealed a protacted magmatic evolution which may be genetically linked with the oldest plutons (2250-2200Ma) located southward of LSZ. Tectonically this oldest magmatism may result from NW-SE subduction (present-day position) of oceanic lithosphere occurring outboard of the evolving passive margin. In contrast, the bulk of the Mantiqueira rocks gives TDM ages between 3.4-2.9Ga (εNd(t) from -10 to -13) and 2.7-2.4Ga (εNd(t) from -7 to -3). They originated by SE-NW subduction of the lithosphere below an active continental margin, after stacking of the 2.25-2.20Ga accretionary prism. The resulting paleotectonic scenario may explain a strong magnetic anomaly typical of crustal descontinuity recognized between the Paleoproterozoic terrain and the São Francisco paleocontinent.
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