2020-01-102020-01-102016-11-14MAGALHÃES, Lucas Baía. Geocronologia U-Pb da Formação Urupi e geoquímica isotópica Sr-Nd do Grupo Iricoumé, Domínio Erepecuru-Trombetas oeste, província Amazônia central. Orientador: Jean Michel Lafon. 2016. 60 f. Trabalho de Curso (Bacharelado em Geologia) - Faculdade de Geologia, Instituto de Geociências, Universidade Federal do Pará, Belém, 2016. Disponível em: https://bdm.ufpa.br/jspui/handle/prefix/2753. Acesso em:.https://bdm.ufpa.br/jspui/handle/prefix/2753The Erepecuru-Trombetas Domain, northern part of the Central Amazonian Province, exhibit expressives volcano-plutonic associations during Orosirian. The first association represented by the Igarapé Paboca formation and granitoids of Caxipacoré Suite has formed at about 1,99 - 1,96 Ga. The second association represented by Iricoumé Group and the Água Branca e Mapuera suites has formed at about 1,90 - 1,86 Ga. In this Domain, locally there is paleoproterozoic sediments covers represented by the Urupi formation that are overlying the rocks of the Iricoumé Group. Geochronological data of this formation are absents. This work has as main objective to investigate the existence of archean records and to contribute to the understanding of the Paleoproterozoic (Orosirian) evolution through the samples of the Iricoumé Group and the Urupi Formation, Erepecuru-Trombetas Domain. The employed methods are petrography, the dating from magmatic rocks through Pb evaporation from zircon, dating of detritical zircons trough LA-ICP-MS of sedimentary rocks and Nd-Sr isotopic geochemistry. The ages of the zircons of a rhyolite from the Iricoumé Group range from 1970 ± 28 Ma to 1881 ± 7 Ma (Pb-Pb method). The interpretation of these ages was that the age of crystallization is 1.89 Ga and older ages represent inherited components/inherited zircons from rocks generated in the oldest magmatic episode of 1,99 Ga. The Nd-TDM and Sr-TUR model ages obtained in volcanic rocks of the Iricoumé Group range between 2,30 and 2,08 Ga (Rhyacian period) and from 2.26 to 1.91 Ga, respectively. The results do not show evidence of archean sources in the origin of the Proterozoic magmas. The Urupi formation contain quartz sandstone (> 95% quartz) with subrounded to subangular grains with the presence of some lytic fragments and cherts. The detrital zircons from this quartz-sandstone were characterized by SEM (scanning electron microscopy) by its texture and morphology as to being prismatic crystals, had finely spaced oscillatory zoning, and some with high concentrations of U. The U-Pb in situ analysis by laser ablation mass spectrometry (LA-ICP-MS) carried out on these zircons indicate two populations of different ages. The first rhyacian population presents ages ranging between 2167 Ma and 2050 Ma. The second neoarchean population provides ages between 2761 Ma and 2573 Ma. The probably source of those detrital zircons is the Transamazonian Province, adjacent to the east of Central Amazon Province. In particular, the sources of the most Archean zircons are the Amapá Block and rhyacian zircons are from both the rhyacian rocks from Amapá Block as the Carecuru and Parú Domain. The youngest zircon grain obtained was 1.971 ± 9.2 Ma (207 Pb / 206 Pb). Therefore, the Urupi formation must be younger than the magmatism of 1.99 Ga for the fact of having a concordant zircon related to Formação Igarapé Paboca and intrusive suite Caxipacoré.Acesso AbertoGeocronologiaGeologia – ParáArqueano - PaleoproterozoicoCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIA::GEOCRONOLOGIATrabalho de Curso - Graduação - Monografia