2019-08-052019-08-052010BARRETO, Carla Joana Santos. Caracterização geológica, geoquímica e geocronológica do magmatismo transamazônico na região central do Amapá. Orientador: Jean Michel Lafon. 2010. 113 f. Trabalho de Curso (Bacharelado em Geologia) – Faculdade de Geologia, Instituto de Geociências, Universidade Federal do Pará, Belém, 2010. Disponível em: http://bdm.ufpa.br/jspui/handle/prefix/1590. Acesso em:.http://bdm.ufpa.br/jspui/handle/prefix/1590The main geological evolution of the Amapá state, southeastern Guyana Shield, is related to the Transamazonian orogeny. The State is divided in a northern domain consisting of Paleoproterozoic granitoids and orthogneisses and a central-southern domain, called the Amapá block, which is composed by Archean rocks reworked during Paleoproterozoic. The study area is located in central Amapá state, at the transition between the two domains. The studied geological units are Calc-alkaline granitoids, Peraluminous granites, Sucuriju granite and Santo Antônio tonalite. The aim of this work was to investigate the boundaries between two Archean and Proterozoic domains in southersn Guyana Shield, characterizing the Paleoproterozoic magmatism in central Amapá through petrographical, geochemical and zircon Pb-Pb geochronological studies. Nine samples from granitoids were used, with four of them belonging to the northern portion of Serra do Navio and five samples from Amapá block, the latter associated with metavolcanosedimentary sequences from Vila Nova group. Petrography defined tonalite to granodiorite rocks for Calc-alkaline granites; syeno- to monzogranites for the Peraluminous granites and Sucuriju granite and tonalite rocks for the Santo Antônio tonalite. Geochemical characterization of Calc-alkaline granites pointed out a peraluminous character, affinity with volcanic arc granites and ressemblance with type I granites. Sucuriju granite and Peraluminous granites displayed alkaline nature, slightly peraluminous and affinity with volcanic arc granites and Type I granites. Santo Antônio tonalite showed calc-alkaline affinity, metaluminous character and affinity with volcanic arc and type I granites. Geochronological results furnished crystallization ages of 2262 ± 1,6 Ma for Santo Antônio tonalite, characterizing an early magmatic episode in Transamazônico orogeny, close to 2,23- 2,25 Ga ages obtained by Tavares (2009) in Serra do Navio. Pb-Pb ages on zircon from Calcalkaline granites (2103 ± 2,5 Ma and 2096 ± 3,9 Ma) indicated another event of granite formation around 2,10 Ga. Geochronological results obtained for Peraluminous granites and the Sucuriju Granite, although not reliable, pointed to a ages around 2,08-2,02 Ga, and up to 2,73 Ga suggesting a late-Transamazian magmatic event caused by melting of Archean continental crust. Petrographical, geochemical and geochronological data confirmed that the boundary between the Paleoproterozoic domains took place just at north of Serra do Navio.Acesso AbertoGranitóidesOrogênese TransamazônicaAmapá - EstadoCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIATrabalho de Curso - Graduação - Monografia