2019-07-152019-07-152009NEVES, Manuely Pereira . Petrografia de carbonatos da Formação Itaituba (Carbonífero superior), Bacia do Amazonas, Região de Monte Alegre, PA. Orientador: Werner Truckenbrodt. 2009. 71 f. Trabalho de Curso (Bacharelado em Geologia) – Faculdade de Geologia, Instituto de Geociências, Universidade Federal do Pará, Belém, 2009. Disponível em: http://bdm.ufpa.br/jspui/handle/prefix/1560. Acesso em:.http://bdm.ufpa.br/jspui/handle/prefix/1560The Itaituba Formation (Pennsylvanian age) in the Monte Alegre region is characterized by limestones interbedded with carbonatic shales and less frequently sandstones. The fauna of this formation is represented mainly by brachiopods, echinoderms, molluscs, foraminifera and sporadically by ostracods, trilobites, bryozoans and algae. The microfacies study determinated 8 types of microfacies, being the most predominant the mudstone with terrigenous grains and few bioclasts, followed by grainstones, dolomites, and hybrid packstones and wackstones. Unless the grainstones these microfacies suggest a lagoon environment influenced by continental/transicional sedimentation. Regarding the oolithic bioclastic grainstone and oolithic peloidal grainstone they indicate more agitated waters of tidal bar or shoal environment of the internal platform. The diagenesis of the limestones is characterized by bioturbation and micritization, followed by cementation, silicification, dolomitization and pyritization. The mechanical compaction is evidenced by the presence of fractures, while stylolithes and dissolution seams indicate chemical compaction. The insoluble fraction is predominantly silty clay, and together with the sand fraction (> 62μm) constitutes 2 to 30% of the rock. The most abundant clay mineral is illite, followed by smectite and traces of chlorite and kaolinite. The climate during the deposition of the Itaituba Formation is considered to be moderate with a trend to aridity supported by the presence of Illite, smectite and feldspars. Furthermore, the terrigenous silty quartz in the limestones suggests eolic transport.Acesso AbertoFormação ItaitubaCarbonatosSedimentação e depósitosBacia do AmazonasMonte Alegre - PACNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIATrabalho de Curso - Graduação - Monografia