The Passo Feio Complex revisited: new constraints on its polyphasic origin and evolution (Dom Feliciano Belt, Southern Brazil)

Available data from the Passo Feio Complex in southernmost Brazil present some geological inconsistencies. An integrated analysis of U-Pb detrital zircon data from metavolcano-sedimentary rocks, including five new samples, reveals three main source patterns: (i) Paleoproterozoic–Paleoarchean (1.7–3.5 Ga; peaks at 2.4, 2.1, and 1.8 Ga), (ii) Mesoproterozoic–Eoarchean (1.1–3.6 Ga; peaks at 2.4 and 2.0 Ga), and (iii) Ediacaran–Neoarchean (0.58–2.8 Ga; peaks at 820, 780, and 580 Ma). Patterns 1 and 2 define Sequence 1, with a 1.1 Ga maximum depositional age, Paleoproterozoic zircon dominance, minor Archean and Mesoproterozoic input, and no Neoproterozoic grains. Pattern 3 defines Sequence 2, with a maximum depositional age of 580 Ma and dominant Neoproterozoic provenance. Sequence 1 likely records input from the Nico Pérez, Luis Alves, Taquarembó, Congo, and Kalahari blocks. Sequence 2 reflects contributions from the São Gabriel Block, Tonian complexes, post-collisional granitoids, and eroded basement. Sequence 2 deposition (630–580 Ma) is partially chronocorrelated to the Camaquã Basin, and may represent a metamorphosed portion of that basin, affected by the 565 Ma tectonometamorphic event. The presence of more than two depositional sequences in the Passo Feio Complex is likely and may guide further studies.