Geology of Brazil Essay Example | Topics and Well Written Essays - 1250 words

Geology of Brazil - Essay Example The six major groups that constitute the Brazilian population are the Portuguese who colonized Brazil in the 16th century, Africans brought to Brazil as slaves, European, Middle-Eastern, and Japanese and other Asian immigrant groups who settled in Brazil since the mid-19th century. Further, the indigenous people of Tupi and Guarani language stock. â€Å"Although the major European ethnic stock of Brazil was originally Portuguese, subsequent waves of immigration contributed to a diverse ethnic and cultural heritage† (BWHA 2011). Thesis Statement: The purpose of this paper is to investigate the geology of Brazil in order to gain an appreciation of the land, history and dynamics of the home country. The Geology of Brazil Brazil is located within the South American Platform with its basement consisting of a highly complex geologic evolution beginning from the Archaean period. The region of Brazil had become completely consolidated â€Å"between the Proterozoic Superior period and the beginning of the Palaeozoic period, with the closing in the Brazilian cycle† (Machado, 2011). ... Brazil Geology: Crystalline Shields and Sedimentary Basins (Machado, 2011)       Crystalline shields    Sedimentary basins    The Crystalline shields and the sedimentary basins of Brazil are clearly demarcated above (Fig.1). The shield of Guyana extends to the north of the basin of Amazonas; â€Å"the shield of the Brazil-central, or Guapore extends to the interior of Brazil and south of that basin, while the Atlantic shield is exposed in the oriental portion reaching the Atlantic border† (Machado, 2011). These shields are exposed in over half the area of Brazil. On that platform in Brazil were developoed three extensive basins with sineclisis character: Amazonas, Paraiba and Parana, which developed by filling spatially with sedimentary and volcanic coverings during stable conditions of ortho-platform originating from Ordovician-Silurian. Additionally, several other smaller basins including coastal basins and other sedimentary areas, occur exposed on the platform. The Carajas region in the Amazon belt of Brazil reveals a number of important features regarding the reactivation of Archaean basement terrains. A general increase in temperature is linked to deformation through time that is consistent with progressive exhumation of the crust. Similar embrittlement sequences are recognized in many other long-lived basement shear zones. Secondly, the regional basement fabrics are steeplyh dipping and trending east to west. Those deformations that followed are wrench-dominated events probably because the foliation orientation favours strike-slip, as opposed to dip-slip reactivation. Thirdly, the location of the younger Cover Assemblage rocks is structurally controlled by strike-slip fault zones. On the other hand, however, faulting entirely post-dates the deposition and does