2018-10-022018-10-022003-02-28CHAVES, César Lisboa. Caracterização geológica, petrográfica, geoquímica e geocronológica do magmatismo granítico da região de Porto Nacional-TO. Orientador: Paulo Sergio de Sousa Gorayeb. 2003. 150 f. Dissertação (Mestrado em Geologia e Geoquímica) - Instituto de Geociências, Universidade Federal do Pará, Belém, 2003. Disponível em: http://repositorio.ufpa.br/jspui/handle/2011/10271. Acesso em:.https://repositorio.ufpa.br/handle/2011/10271In the Palmas-Porto Nacional region, Tocantins state, a series of granitic bodies has been assigned to two distinct magmatics events: a) Paleoproterozoic Granites (Areias, Carmo, Itália and Ipueiras plutons); b) Neoproterozoic Granites (Lajeado, Aroeira, Matança and Palmas plutons). Cartographic, petrographic, lithochemical and geochronological studies revealed the main characteristic of these granitic bodies and allowed to improve the knowledge of the granitic magmatism of this region. The Paleoproterozoic granites constitute large bodies affected by small strike-slip zones. Petrographically they are represented by sienogranite, monzogranite and quartz syenite, with different amounts of amphibole and biotite. The geochemical signature of the Paleoproterozoic granites are similar. The show a subalcaline character, and are peraluminous to metaluminous. They are rich in REE and, generally, more fractioned in LREE, with negative Eu anomaly and may be classified as A-type granites. Single zircon Pb-evaporation dating of Areias, Ipueiras and Itália granites gave ages of 2086  5 Ma, 2073  2 Ma and 2078  4 Ma, respectively, interpreted as age of emplacement of these plutons. Sm-Nd TDM model ages between 2.19 Ga and 2.15 Ga suggest that these granites were formed by partial melting of Paleoproterozoic juvenile crust. The Nd(2,08Ga) values between +2.26 and +2.89 indicate the mantelic contribution for the formation of these plutons. The Neoproterozoic granites are petrographically classified as sienogranite, monzogranite and quartz sienite with different amounts of ortopyroxene, amphibole and biotite, In general, they may be called charnockites. The geochemical date revealed similarities among the Neoproterozoic granites. They show subalkaline nature and have metaluminous to peraluminous character. These granites are rich in REE and are more fractioned in HREE than LREE. In the geochemical diagrams they plot in the field of the A-type granites. The Sm-Nd isotopics studies for Neoproterozoic granites revealed TDM ages between 2.1 Ga and 1.71 Ga and the Nd(0,55Ga) values between –13.34 and –9.77 that are interpreted as evidence of strong crustal contribution, but probably with some mixtures of younger of sources. This study corroborated the presence of two main events of granite geration in the Porto National-Palmas region. The older is represented by the Paleoproterozoic Carmo, Areias, Ipueiras and Italia granites, with age around 2.08 Ga. The younger granitogenesis is represented by Lajeado, Palmas, Matança and Aroeira bodies emplaced in the Neoproterozoic at 0.55 Ga.Acesso AbertoGranitogêneseGeologiaPetrografiaGeoquímicaGeocronologiaPaleoproterozóicoNeoproterozóicoPorto Nacional - TODissertaçãoCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS