Basement inliers of the Brasiliano structural provinces of South America

Abstract

Basement inliers, commonly known as terranes, are important tectonic elements in orogenic belts of all ages the world over. Since their identification and initial description in the 1970–1980s, understanding of their relevant role in the structure and evolution of fold belts has increased considerably, allowing to recognize many different types of tectonostratigraphic terranes. In this work, we review tectonostratigraphic terranes that have tentatively been recognized or identified within the Neoproterozoic Brasiliano fold belts exposed in the Tocantins, Mantiqueira and Borborema provinces of the South American platform. In the Tocantins Province, central Brazil, tectonostratigraphic terranes were recognized in the Araguaia Belt (Porto Nacional Terrane), in the Paraguay Belt (Rio Apa Block) and a few are known from the Brasília Belt (Cavalcante-Natividade Terrane, Goiás Massif microcontinent, Ilicínea-Piumhi nappe zone, Amparo-Pouso Alegre-Heliodora window). The Cavalcante-Natividade Terrane is taken as a former promontory of the São Francisco paleocontinent. Over the years, a number of tectonostratigraphic terranes were described in the Mantiqueira Province, east, southeast and south Brazil and Uruguay, including the Guanhães, Gouveia and Porteirinha terranes within the Araçuaí Belt; the Central, Costeiro, Cabo Frio, Embu, São Roque, Itaiacoca, Água Clara, Lajeado, Votuverava, Curitiba and Paranaguá terranes, the Apiaí Superterrane, the Luís Alves microplate and the debatable “Occidental Terrane” within the Ribeira Belt; and the Nico Pérez, Punta del Este and Jaguarão terranes within the Dom Feliciano Belt. The Borborema Province is long known for its mosaic-like structural organization, with a number of basement inliers branching out several Brasiliano fold belt systems in all four subprovinces: the Granja Terrane in the Médio Coreaú subprovince (northwestern part); the Troia-Tauá, Granjeiro, Rio Piranhas and São José do Campestre terranes in the northern subprovince; the Alto Moxotó, São Pedro and Tonian terranes (Alto Pajeú, Riacho Gravatá, Riacho do Tigre), as well as several smaller dispersed terranes (Açude Coremas, São José do Caiana, Icaiçara) in the Transversal Zone; the Pernambuco-Alagoas Superterrane, the Itabaiana dome and Simão Dias sliver within the Sergipano Belt; and the Paulistana dome, Morro do Estreito sliver and Sobradinho Superterrane, the latter behaving as a large forebulge within the Riacho do Pontal and Rio Preto fold systems, in the southern subprovince (at the north of the São Francisco Craton).