ABSTRACT
The South American continent hosts three large tectonic domains: the Andes, the Patagonic platform, and the South American platform. Exception should be made to a small part of Venezuela that belongs to the Caribbean plate. The South American plate, where Brazilian territory is situated, corresponds to the continental portion of the homonymous plate, which has remained stable as a foreland against the Andean and Caribbean mobile belt and continental drifting during the Meso-Cenozoic period. It has undergone multiple tectonic cycles between the Paleoarchean up to the Ordovician resulting in a complex framework. Phanerozoic covers have developed since then, setting the beginning of its stabilization phase (CPRM, 2003). The Brazilian orogenic cycle activities lasted up to the Upper Ordovician/Lower Silurian whereby the actual tectonic framework of the Brazilian territory has been built. Microcontinents and continental blocks were transformed giving rise to the actual cratonic areas (Amazônico, São Francisco, São Luis, and Paraná) allowing ocean development (Borborema, São Francisco, Goiano, and Adamastor), where a whole set of sedimentary rocks, insular and juvenile continental arc portion shad has undergone metamorphism, deformation, and emplacement of granitic intrusions across multiple events. During its stabilization period, large synecleses have been developed, such as Amazonas (500,000 km2), Solimões (600,000 km2), Parnaíba (700,000 km2), and Chaco-Paraná (1,700,000 km2). Besides the large basins, many other small ones were originated (Parecis/Alto Xingu, Alto Tapajós, Tacutu, Recôncavo/Tucano/Jatobá, Araripe, Iguatu, Rio do Peixe, and Bacia Sanfranciscana). Across its continental margin, a great number of mesozoic basins have been developed (Pelotas, Santos, Campos, Espírito Santo/Mucuri, Cumuruxatiba, Jequitinhonha/Camumu/Almada/Jacuípe, Sergipe/Alagoas, Pernambuco/Paraíba, Potiguar, Ceará, Barreirinhas, Pará/Maranhão, Foz do Amazonas, Cassiporé, Marajó, Bragança/São Luís, Barra de São João, and Taubaté). Widespread Cenozoic deposits with heterogeneous thickness cover large portions of the territory. The main units are formation Solimões, Içá, Boa Vista, Pantanal, Araguaia, and Barreiras. The continental area occupied by sedimentary basins is 4,898,050 km2, from which 4,513,450 km2 (70%) are intracratonic and the remaining 384,600 km2 (30%) are lying on the continental margin. Figure 3.1 presents the main basins and sedimentary cover within Brazil. The cratonic areas are composed of plutonic rocks, gneisses, migmatites TTG, and greenstone belts sequences while in the orogenic belts there is a predominance of metasedimentary sequences and intrusive bodies. Some neo-proterozoic and cambri-ordovician basins such as AltoParaguai, Bambuí, Chapada Diamantina, Paranoá, Santo Onofre, Estancia, Rio Pardo, and Jaibaras, among others contain sedimentary sequences bearing primary structures and low metamorphic grades behaving mostly as fractured aquifers.
