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) Depósitos costeiros e microbialitos da Formação Itaituba, o Pensilvaniano da borda sul da Bacia do Amazonas, região de Placas, Pará.(Universidade Federal do Pará, 2019-12-29) OLIVEIRA, Fernando Andrade de; ROMERO, Guilherme Rafaelli; SILVA JUNIOR, José Bandeira Cavalcante da; http://lattes.cnpq.br/8615194741719443The Itaituba Formation in the Amazon Basin represents a Bhaskiriana-Moscowian carbonate succession, composed of fossiliferous limestone, fine dolomite, fine to coarsegrained sandstone, gray shales and evaporites. Outcrop-based facies and stratigraphic analysis combined with microfacies study allowed the paleoenvironmental reconstitution of the Itaituba Formation, on the southern border of the Amazon Basin, Southwestern of Pará State. The 14mthick carbonate succession with occurrence of microbialites, consists of 9 facies and microfacies, such as: a) laminated shale (F1); b) laminated sandstone (Al); c) laminated siltstone (Sl); d) massive sandstone (Mm); e) mudstone with desiccation cracks (Mg); f) wackestone bioclastic (Wb); g) packstone bioclastic (Pb), h) oncolitic floatstone (Fo) and i) boundstone. These facies are grouped into two facies association (AF): AF1, lagoon / tidal flat deposits, consisting of facies Fl, Al, Sl, Mm, Mg, Wb, related to the flat and laterally continuous buildings with predominance of facies F1, interlayed by centimeter layers of facies Wb and Pb, organized in a fining upward cycle and; and AF2, shoal / barrier island, constituted by Pb facies and Fo and Bd facies, with Pb displayed in continuous flat and lateral bodies and Fo and Bd in lensshaped bioherms. Fo facies are the oncolytic microbilites and associated with microstromatolites, described as M1 and M2a morphotypes, and Bd facies, include columnar stromatolitic forms, described as M2b and M2c morphotypes. The depositional model of the Itaituba Formation in the Placas-PA region consists of a coastal system with lagoon, shoals / barrier island and tidal flat. Microbialites developed in the coastal region in the Amazon Basin during the Bashkirian-Moscovian transition, representing a transition to more restrictive environmental conditions in relation to fauna and flora, and more conducive to the proliferation of cyanobacteria, with probably increased alkalinity in water. These cyanobacteria evidences are record, for the first time, in Carboniferous rocks of the Amazon Basin improved the knowledge related to the carbonate fabric dispersion during the implantation of the Itaituba epicontinental sea in the Western Gondwana.Item Acesso aberto (Open Access) Mineralogia e geoquímica do perfil laterito bauxítico na serra Sul, Província Mineral de Carajás(Universidade Federal do Pará, 2020-11-03) RODRIGUES, Paulo Ronny Soares; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302The Amazon holds the largest reserves of bauxites in Brazil, located in Trombetas, Juruti, Paragominas and Rondon do Pará. The Carajás region, with large lateritic deposits, especially of iron, is also emerging with potential for bauxite deposits, with emphasis on those of Serra Norte. In Serras Sul, smaller occurrences were identified, which were investigated in this work. In this context, field activities were carried out with sample collection and textural, mineralogical and chemical analyzes and then a genetic discussion was presented. In four alteration profiles on a side road near the Serra Sul, after geological cartography, 23 samples were collected, which were described, photographed and prepared for mineralogical analysis (X-ray diffraction), textural (optical and scanning electron microscopy) and chemical (mass and optical emission spectrometry, with inductively coupled plasma). The bauxite laterite profile comprises from the base to the top of: 1) Kaolin Horizon (HC); 2) Mottled clay Horizon (HAM); 3) Nodular Bauxite Horizon (HBN); 4) Clayey Bauxite Horizon (HBA) and 5) Ferruginous crust Horizon (HF); and finally to the top 6) Dismantled crust ferruginous horizon (HFD. The chemical composition is essentially dominated by Al2O3, Fe2O3, SiO2 and TiO2, which compose the main minerals, kaolinite, gibbsite, hematite, goethite and anatase. The trace elements V, Cr, Cu, Ga, As, Zr, Cd, Hf, Bi and Th, whose concentrations are generally higher than those of the Upper Crust of the Earth, are more concentrated in the ferruginous horizons, related to Fe oxy-hydroxides (hematite and goethite) and also to zircon. On the other hand, the elements Co, Zn, Se, Rb, Sr, (Nb), Ag, (Sn), Cs, Ba and Pb are at lower levels than theUpper Continental Crust, and their concentrations are lower in ferruginous horizons, suggesting affinity with clay minerals.ETR at levels lower than UCC, are enriched in ETRP and present strong positive and negative C and positive Eu anomaly, and suggest distribution in zircon, oxy-hydroxides of Fe and other mineral phases. and mass clearly demonstrate a complete lateritic evolution, only partially modified in its upper portion. The bauxite zone, however, does not have local potential for ore, due to the low content of usable alumina and high in reactive silica. However, its occurrence opens an opportunity for further research in view of the geological and paleoenvironmental potential of the Mineral Province of Carajás.Item Acesso aberto (Open Access) Síntese e caracterização da piroaurita a partir de resíduo de mina de cobre e sua aplicação na adsorção do corante vermelho do Congo(Universidade Federal do Pará, 2023-03-24) FERREIRA, Rafaela da Silva; RODRIGUES, Elizabeth Maria S.; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568In this study, the copper flotation tailings extracted from the Sequeirinho pit of the Sossego mine, Carajás region, Southeast of the State of Pará (Brazil), has been used as raw material for the synthesis of Pyroaurite, a potential absorbent of organic dyes. Initially, tailings characterization was performed through X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD) techniques. Next, a sample of this characterized material was leached (HCl 1:1 H2O), the obtained solution was filtered and used in the procedures of Pyroaurite synthesis. This solution was kept in the coprecipitation method at constant pH (14) with Mg/Fe molar ratio equal to 6:1, a dripping time of 4 hours, hydrothermal bath of 24 hours at high agitation rate. After, the synthesized Pyroaurite was submitted to characterization by Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), Specific Surface Area (ASE) and total pore volume (Wo) techniques. Then, the synthesized Pyroaurite was evaluated for the adsorption process of Congo Red (CR) dye, where 0.025 mg of Pyroaurite were added to 10 mL of CR samples at concentrations of 5, 10, 20, 30, 40, 50 and 80 mg·L-1, respectively. The adsorption results fitted to the Langmuir model (R2 = 0.9614), while the kinetics suggested the pseudo-second order model (R2 = 0.9977). In addition, the temperature of 40ºC showed to be the most pleasant for the adsorption of the CR dye. Finally, the thermodynamic parameters of entropy (ΔSº= 0.0886 kJ·mol-1·K-1) and enthalpy (ΔHº= 8.2999 kJ·mol-1) show that the adsorption process was found to be naturally spontaneous and endothermic.Item Acesso aberto (Open Access) Síntese e caracterização de hidróxidos duplos lamelares de Mg/Fe com esferas de carbono magnéticas(Universidade Federal do Pará, 2021-10-26) SILVA, Victor Coutinho Gonçalves; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568This research aimed to synthesize a stable magnesium/iron carbonate (Mg//Fe-CO3) lamellar double-hydroxide (LDH) compound with magnetic carbon spheres (MCS) in order to evaluate composite’s characteristics. LDHs are synthetic or natural anionic clays which structures are constituted of positively charged octahedral lamellas with intercalated di- and trivalent cations, and hydroxyls in the vertices. Water and anions are also in the inter-layered space. Spheric carbon products are known for a long time and the application of carbon nanomaterials is possible in many areas. The formation process of this material is hydrothermal, which does not result in singular products. Its results are big interconnected chains of carbon spheres (CS) attracted by Van der Waals forces. Chemical reagents of analytical purity were utilized in the synthesis. Mg/Fe-CO3 LDHs were synthetized by co-precipitation method with variable pH. And the hydrothermal method was applied to prepare the carbon spheres. The characterization of LDH, CS, MCS and LDH + MCS composite included analysis by X ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), infrared vibrational spectroscopy and Brunauer-Emmet-Teller method (BET) for specific surface area and pore size measurement. XRD analysis identified pyroaurite’s structure in the HDL samples and magnetite’s structure in the MCSs. The average values of pyroaurite’s unit cell, a = b parameters, interplanar distance (c) and interlamellar spacing thickness were 7,792 Å, 3,107 Å, 23,375 Å and 2,992 Å, respectively. Photomicrography was performed only in CS and MCS samples. It was possible to observe big agglomerates and chains of these materials, and the size variation between different samples and synthesis as well. Thermic decomposition of synthetic pyroaurite and the composite occurs in a similar way, which can be divided in five stages. Loss of adsorbed water and intercalated water elimination happen in the first (31-72 °C) and second (175-177 °C) stages, respectively. Then, between 284 °C and 395 °C, there is decarbonization and desidroxylation. Finally, the destruction of LDH’s structure happens at 746 – 786 °C. Intercalated anion in LDH’s structure was determined as a carbonate anion (1365 cm-2) by infrared vibrational spectroscopy. Carbonate anion and water fill the inter-layered spaces of LDH and LDH + MCS composite. Both LDH and LDH + MCS composite show infrared isotherms and type H3 hysteresis, according to IUPAC’s classification. Superficial area increased by 15-31%, while the size and volume of pores decreased by 44-49% and 26-42%, respectively.