Zircon geochronology and Sm-Nd isotopic study: Further constraints for the Archean and Paleoproterozoic geodynamical evolution of the southeastern Guiana Shield north of Amazonian Craton, Brasil

• Autor(a) principal: ROSA-COSTA, Lúcia Travassos da
• Data de Publicação: 2006
• Outros Autores: LAFON, Jean-Michel, DELOR, Claude
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional de Geociências - RIGEO
• Texto Completo: https://rigeo.cprm.gov.br/handle/doc/582
• topic: GEOCRONOLOGIA; GEOQUÍMICA; PALEOPROTEROZOICO; OROGÊNESE; BRASIL; AMAZONAS

The eastern part of the Guiana Shield, northern Amazonian Craton, in South America, represents a large orogenic belt developed during the Transamazonian orogenic cycle (2.26-1.95 Ga), which consists of extensive areas of Paleoproterozoic crust and two major Archean terranes: the Imataca Block, in Venezuela, and the here defined Amapá Block, in the north of Brazil. Pb-evaporation on zircon and Sm Nd on whole rock dating were provided on magmatic and metamorphic units from southwestern Amap¨¢ Block, in the Jari Domain, defining its long-lived evolution, marked by several stages of crustal accretion and crustal reworking. Magmatic activity occurred mainly at the Meso-Neoarchean transition (2.80-2.79 Ga) and during the Neoarchean (2.66-2.60 Ga). The main period of crust formation occurred during a protracted episode at the end of Paleoarchean and along the whole Mesoarchean (3.26-2.83 Ga)........ The lithological association and the available isotopic data registered in the Carecuru Domain suggests a geodynamic evolution model based on the development of a magmatic arc system during the Transamazonian orogenic cycle, which was accreted to the southwestern border of the Archean Amapá Block