Dissertações em Geologia e Geoquímica (Mestrado) - PPGG/IG
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2604
O Mestrado Acadêmico pertence ao Programa de Pós-Graduação em Geologia e Geoquímica (PPGG) do Instituto de Geociências (IG) da Universidade Federal do Pará (UFPA).
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Item Acesso aberto (Open Access) Caracterização hidrogeoquímica do reservatório da Usina Hidrelétrica de Coaracy Nunes-Amapá(Universidade Federal do Pará, 2012-07-03) BEZERRA, Clauber dos Santos; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568This study characterized chemically the water of the reservoir of the hydroelectric power plant of Coaracy Nunes, located in the Amapá state, about 20 km from the city Ferreira Gomes and 150 km from the city of Macapa. Samples were collected in four quarterly campaigns during the year, in the period October 2008 to September 2009, the study aimed to characterize the spatial and seasonal behavior of chemical parameters, and physicalchemicalsof the water in thereservoir of the hydroelectric power plant of Coaracy Nunes. In the Amapá state, the predominant climate is equatorial, in the months of the campaigns, from December to May was the period with the high estrate of rainfalls, and the months of lowest rainfalls was understood from August to November. In the total 13 point were sampled in each campaign, distributed upstream of the reservoir in order to represent all environments of the reservoir. At each point, samples were collected from water at four depths (surface, double the secchi, middle and bottom). In the collected samples were measured physicochemical parameters such as pH, temperature, conductivity, ammonium ion, STS, HCO3-, hardness and OD. The chemical elements(Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K, Li, Mg, Mn, Na, Ni, Pb, Se, Sr, V, Zn) were analyzed by mass spectrometry of a source for inductively coupled argon plasma. (ICP-MS). In preliminary assessments none showed evidence stratification in the reservoir. The concentrations of aluminum,iron and manganese are highlighted within this context, and have high concentrations, once compared with the chemical characteristicsofwatersofthe Amazon region. The reservoir had the following chemical and physical-chemical particulars average values obtained during dry periods in (μg/L) : Al (487,44), Ca (604,12), Fe (458,78), K (798,05), Mg (625,40), Mn (123,42), Na (1903,719), Pb (3,86), pH (6,50), Cond. (μs/cm) (33,20), temperature ºC (27,1), hardness mg/L (6,09), HCO3 -(9,00). The reservoir of Coaracy Nunes presented a tendency to stratification in the deepest collection stations indicated by the points MCN 02, MCN 03 e MCN 04, in other points this trend is less marked, because the other points have less depth. Throughout the longitudinal axis of the reservoir we did not observe any tendency of the reservoiractasaretention systemofsubstancein relationtothat flock toit. Sampling points in greater depth, the reservoir has decreased the concentration of dissolved oxygen with increasing depth,creating anoxic zones in the reservoir bottom, favoring the release of chemical elements as Fe and Al which are incorporated to the particles in suspension, through the anaerobic processes.Item Acesso aberto (Open Access) Evolução geológica da região de Tucuruí - Pará(Universidade Federal do Pará, 1982-05-27) MATTA, Milton Antonio da Silva; HASUI, Yociteru; http://lattes.cnpq.br/3392176511494801The northern part of the Araguaia Belt is exposed in the Tucuruí region and their stratigraphic, structural, metamorphic and magmatic features had been studied aiming at contributing for the understanding of the geological evolution of the area. The oldest stratigraphic unit of the area is represented by the Xingu Complex, composed by gneisses and granitos and subordinated schists and anphibolites. These rocks show evidence of a polycyclic metamorphic and structural history. Over this unit, during the niddle Proterozoic, the Tucuruí Group was developed. The bottom of this unit is composed by a sequence of tholeiitic basal-tic flows which were hera enclosed in the Caripé Formation. The Morrote Formation, is made up of graywackes, and constitutes the upper part of the Tucurui Group. The geossinclinal evolution of the Araguaia Belt took place during the Uruaçuano Cycle. This geotectonic unit is represented in the studied area by the Couto Magalhães Formation (Tocantins Group) which comprises pelitic and psamitic metasediments. These rocks show a greenshist facies metamorphism and structures generated by two phases of deformation in conditions of lower structures level. After the metamorphism of the Araguaia Belt, the Couto Magalhães Formation acted as the place of mafic and ultramafic intrusion and, lately, the Tucuruí Fault thrusted the metamorphic rocks of the Tocantins Group over the Tucuruí Group lithotypes. This faulting, besides generating a. series of structural features in the both groups as well as in the later migmatites, has also induced a dynamic metamorphic event into the rocks under green-schist facies conditions. Through the statistic treatment of structural data from the denso fault population which cuts the area, it was possible to deduce the shertening and the eterlding directiors related to the progressivo deformation induced by the thrust faulting had acted from E to W. Post-faulting mafic dykes represent the last magmatic event related to the Mesozoic Era. During the Cenozoic the area was a place of Tertiary sedimentation (Barreiras Formation), with sand, clays and conglomeratic levels. A final reactivation was responsible for the fracturing and faulting showed by the Barreiras Formation lithotypes Quatérnaty deposits mostly alluvial sediments, are the final units of the area.