Produção Nacional
GEOQUÍMICA E GEOCRONOLOGIA PB-PB EM ZIRCÃO DA SUÍTE INTRUSIVA ÁGUA BRANCA, MUNICÍPIO DE PRESIDENTE FIGUEIREDO (AM): EVIDÊNCIAS DE COLISÃO NO PALEOPROTEROZÓICO DA AMAZÔNIA OCIDENTAL
2006; Sociedade Brasileira de Geologia; Volume: 36; Issue: 2 Linguagem: Inglês
10.5327/rbg.v36i2.1235
ISSN2317-4889
AutoresCristóvão da Silva Valério, Valmir da Silva Souza, Moacir José Buenano Macambira, Marco Antônio Galarza,
Tópico(s)Geological and Geochemical Analysis
ResumoThe calc-alkaline granitoids of the President Figueiredo district, Amazonas State, Brazil, are represented by syenogranites, monzogranites and diorites of the Agua Branca Intrusive Suite that display porphyry, equigranular, mylonitic and granophiric textural variation. This unit is characterized as a granitic series that presents expanded values of SiO 2 , Al 2 O 3 , Fe 2 O 3(total) , MgO, CaO and Na 2 O+K 2 O, and relative homogeneity in Fe/Mg ratio, suggesting an origin from magmas of the calcalkaline granodioritic series. The high values in Ba, Sr and Rb/Zr, and low values in Nb, Rb, Ta, Zr, Zn, Y, K/Rb and LREE of Agua Branca Intrusive Suite, added to the REE and multi-elements distribution pattern, indicate a sin-collisional tectonic setting with formation of magmatic arc and generation of rocks with metaluminous to peraluminous, calc-alkaline from medium to high-K and I normal type or weakly fractionated geochemical characteristics. The strong homogeneity between compatible and incompatible elements distribution of the Agua Branca Intrusive Suite rocks and typically sin- to post-collision rocks, contributes with a proposal of a collision regime involving the final subduction-related collage processes, of the oceanic paleoplate under the Amazonian protocraton (Central Amazonian Province), and subsequent construction of the Ventuari-Tapajos Province, associated to the Agua Branca magmatism, ca. 1.89 Ga. The geological, geochemical and geochronological data suggest stratigraphic correlation between Agua Branca Intrusive Suite and (Parauari) Tropas Intrusive Suite from Tapajos Gold Province, southern portion of the Ventuari-Tapajos Province.
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