2019-08-292019-08-292011-02ABRANTES JUNIOR, Francisco Romério. Reconstituição Paleoambiental do limite permiano-triássico da bacia do parnaíba, região do Loreto (MA). Orientador: Rômulo Simões Angelica. 2011. 77 f. Trabalho de conclusão de curso (Bacharelado em Geologia) -- Faculdade de Geologia, Instituto de Geociências, Universidade Federal do Pará, Belém, 2011. Disponível em: http://bdm.ufpa.br/jspui/handle/prefix/1798. Acesso em:.http://bdm.ufpa.br/jspui/handle/prefix/1798The Permian-Triassic boundary is marked by paleoenvironmental, paleoclimatic and geochemical global changes, partly attributable to catastrophic events. The intense continentalization of supercontinent Pangaea with the development of extensive deserts succeeded Permian coastal to platform setting. The records of these events in the northern Brazil are found in intracratonic basins, particularly in the Parnaíba Basin, where the Permian-Triassic boundary include the contact zone between the siliciclastic deposits of Motuca and Sambaíba formations. Facies, stratigraphic and geochemical study of outcrops of these units in the Loreto region, State of Maranhão, allowed reconstructing the paleoenvironment and to infer the possible disturbances in the geochemical cycle. The upper Motuca Formation consists of siltstones, mudstones and fine-grained sandstones with even parallel stratification, sigmoidal cross bedding, interpreted as lacustrine/deltaic deposits. The basal Sambaíba Formation consists of fine to medium grained sandstones with well rounded grains, even parallel stratification, medium- scale cross-bedding, convolute lamination and sin-sedimentary faults, interpreted as marginal dune-field deposits. The metastable heavy minerals like garnet, apatite and kyanite dominated lacustrine/deltaic deposits, while zircon, tourmaline, rutile, staurolite are common in deposits of the marginal dune-field. Provenance preliminary data suggest reworking of the units of the basin and sourcelands of igneous and metamorphic rocks. Geochemical anomalies in trace elements like Mn, Cr, Co, Cu and Ni in the Permian- Triassic boundary can indicate leaching of elements or concentration related to catastrophic event triggered by meteorite impact.Acesso AbertoBacia do ParnaíbaLimite Permiano-TriássicoPaleoambienteFormação SambaíbaCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIATrabalho de Curso - Graduação - Monografia