2019-09-042019-09-042014SANTOS, Pabllo Henrique Costa dos. O perfil laterítico ferroaluminoso da serra do Piriá. Orientador: Marcondes Lima da Costa. 2014. 71 f. Trabalho de Curso (Bacharelado em Geologia) - Faculdade de Geologia, Instituto de Geociências, Universidade Federal do Pará, Belém, 2014. Disponível em: http://bdm.ufpa.br/jspui/handle/prefix/1961. Acesso em:.http://bdm.ufpa.br/jspui/handle/prefix/1961Small lateritic deposits are very common in the Northeast Pará and Northwest Maranhão. The majority is mineralized in aluminum phosphate and forms a set little hills and plateaus that stand out in this region lowered plain. Piriá Mountain is one of the largests deposits, located in the namesake riverbank, county of Vizeu, State of Pará. The Piriá Mountain is a set of NE-SW plateaus with 6km extension and maximum altitude of 110m height. The studied lateritic profile was exposed through a 17m deep hole. From it, 34 samples were collected, which were described, photographed, prepared and submitted to mineralogical analysis by XRD, optical and eletronic microscopy; and chemical analysis aiming to understand the lateritic profile formation process and its insertion in the lateritic regional landscape. The investigated profile is composed of two main horizons, the bauxitic clay (7 to 17m deep) and bauxitic ferruginous crust (above 7m). The bauxitic clay horizon has a sandy-clay aspect, is orange-red and locally shows suggestive primary structures. It is composed by kaolinite, gibbsite, goethite anatase and augelita. The ferruginous crust is brownish-red, is composed of hematitic concretions with goethitic cortex and gibbsitic-goethitic cement. Hematite, gibbsite and goethite are therefore main minerals, with anatase and augelita accessories. Through the optical microscopy, the general aspect comprises microcrystalline minerals disperse in a plasma, which is hematitic, goethitic and gibbsitic (in the crust) and kaolinitic/gibbsitic in the clay horizon. Quartz grains are observed, despite this mineral has not been detected by XRD. The SiO2 content vary from 28 to 0,48%, decreasing from the base to the top, while the Fe2O3 content increases and range 67,8%, the same way the Al2O3 content do, ranging 35%. The inconstant TiO2 content, from 0,65 to 5,7%, suggest heterogeneous bedrock composition. The P2O5 content from 0,22 to 0,72% are lightly high and represent the augelita. The mineralogical composition and the distribution of the main chemical components are compatible with the lateritic evolution, correlated to the oldest Amazon lateritic profiles, known as matures.Acesso AbertoCaulinita - ParáHematita - ParáGoethita - ParáCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIA::MINERALOGIATrabalho de Curso - Graduação - Monografia