Extension and general evolution of the Río de la Plata Craton

Abstract

The Río de la Plata Craton (RPC) comprises part of southern Brazil, Paraguay, Uruguay and the central-eastern sector of Argentina. To the north, the RPC is bounded by the southern Amazonian craton, whereas to the east it is bounded by the allochthonous Cuchilla Dionisio Terrane. The RPC is limited in the west by the Pampia Terrane of Argentina. Three tectono-stratigraphic terranes compose the RPC: the Piedra Alta, Tandilia and Nico Pérez terranes, separated by the first-order Sarandí del Yí and Colonia shear zones. Basement rocks range in age from Archaean to Mesoproterozoic, with Palaeoproterozoic igneous–metamorphic complexes making up most of the Tandilia and Piedra Alta terranes. Neoproterozoic (mainly Ediacaran) sedimentary successions occur in the three terranes, and mainly represent passive margin deposits. Abundant granitic intrusions between 630 and 530 Ma in the Nico Pérez Terrane may represent rift-related granitoids or a transpressive regime with subduction towards the north-northwest during the Brasiliano Cycle.