Geology of Brazil
Ribeira Orogen

The Ribeira Orogen describes an ancient mountain range in the central segment (21°S - 26°S) of the Mantiqueira Province. It was formed towards the end of the Neoproterozoic Brasiliano - Pan African orogenic cycle as part of the evolution of West Gondwana. It can be divided in a southern, central and northern part.

This orogen resulted from the closure of the Adamastor Ocean by convergence and collision of descendants of supercontinent Rodinia / Pannotia including the cratons São Francisco / Congo (SFC) and Rio de la Plata (RP) such as several smaller terranes (Apiaí (A), Curitiba (C) or Juiz de Fora (JF)).

Similar to the Araçuaí - Orogen in the north, nowadays only the Precambrian basement (partly covered by sediments) and a variety of granitic intrusions (plutons) have remained visible to us.

These intrusions are either pre-collisional plutonic remnants of magmatic arcs (e.g. Piên (P) in the south or Rio Negro (RN) in the north) due to subduction or granitic bodies in different sizes due to collisions. These granites are represented in from of large batholiths (e.g. Paranaguá in the south or Serra dos Órgãos in the north), medium sized massives (e.g. Marumbi in the south or Ilha Grande in the north) or smaller stocks such as Corcovado or Sugar Loaf Mountain in Rio de Janeiro.