2019-11-012019-11-012010DUTRA, Alessandra de Cássia dos Santos. A caracterização petrográfica e química do Diabásio Penatecaua, na região de Monte Alegre (PA). Orientadora: Rosemery Silva Nascimento. 2010. 80 f. Trabalho de Curso (Bacharelado em Geologia) - Faculdade de Geologia, Instituto de Geociências, Universidade Federal do Pará, Belém, 2010. Disponível em: https://bdm.ufpa.br/jspui/handle/prefix/2334. Acesso em:.https://bdm.ufpa.br/jspui/handle/prefix/2334In the Amazon Basin located in the region of Monte Alegre, western of the Pará state occur sills and dykes of dolerites intruded in the paleozoic megasequences rocks, with emphasis on the central-southern area, where these rocks form the prominent dome-type structure Monte Alegre. These rocks know as Penatecaua Dolerite are evidences of an expressive basic magmatism that occurred in Lower Jurassic related to the disruption of Pangea and opening of the Central Atlantic. Associated with basic rocks of similar age that occur in other continents in the vicinity of that ocean, the rocks of the study area are within the Central Atlantic Magmatic Province (CAMP). The objectives of this work was the detailed characterization of the petrographic and geochemistry of these rocks. Based on mineralogical and textural features were individualized three sets that are dolerite, olivine-dolerite and olivine-basalt, where the first two are medium and coarse grained and a wide textural variation which, however, is mainly sub-ophitic, while the olivine basalts are porphyritics and have devitrified material. The three groups are composed essentially of labradorite and pigeonite, and opaque minerals and olivine (when present) are varietal and apatite is an accessory. The geochemical aspects in classification diagrams these rocks follow a trend of basaltic andesite to basalt of tholeiitic affinity and geochemistry signatures typical of intracontinental environment, probably derived from an enriched mantle source with limited or no crustal contamination. Whereas the FeOt/MgO reason as index of differentiation with respect to TiO2, most of the studied rocks can be correlated to the group of high-Ti tholeiites of the CAMP, necessitating an even large number of chemical analyses, for a more precise correlation.Acesso AbertoPetrografiaGeoquímicaDiabásio PenatecauaMonte Alegre - PACNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIA::PETROLOGIATrabalho de Curso - Graduação - Monografia