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Teses em Geologia e Geoquímica (Doutorado) - PPGG/IG

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/6341

O Doutorado 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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Acesso aberto (Open Access)
Análise da dinâmica das áreas de manguezal no litoral Norte do Brasil a partir de dados multisensores e hidrossedimentológicos
(Universidade Federal do Pará, 2016-12-16) NASCIMENTO JUNIOR, Wilson da Rocha; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
The objective of this research is to analyze the dynamics of the mangrove areas in the north coast of Brazil from images of remote orbital sensors and hydrosedimentological data (flow and suspened sediment concentration). We tried to understand the existence of causality between the expansion or retraction of the mangroves with the suspened solid discharge calculated from the data of flow and suspened sediment concentration. The mangroves were mapped, using the object oriented classification technique, in the years 1975, 1996 and 2008 based on data from microwave sensors (RADAM / GEMS, JERS-1, ALOS / PALSAR). The data of fluviometric stations and sediments of the National Water Agency were used to calculate the solid discharge in suspension in the rivers Araguari, Gurupi, Pindaré, Grajaú and Mearim seeking to relate the addition and erosion in the areas of mangrove with the sedimentary load of the rivers that drain On the coast. The flow variations reflect the precipitation in the sub-basins of the analyzed rivers and presented a strong and moderate correlation with the temperature anomalies on the surface of the Pacific Ocean evidencing a relation of the El Niño and La Niña phenomena with the precipitation regimes in the Amazon. The variations of suspended sediment concentration were not related to the fluviometric variation suggesting that the annual mean oscillations are reflections of other phenomena (coverage and land use). The results show that the drainage areas of the sub-basins most impacted by the anthropic action contribute with a higher sediment load to rivers that have a higher concentration of native forest. Native vegetation contributes to containment of soil erosion and exposed soil and pasture areas are more vulnerable to soil erosion. The Gurupi, Pindaré, Grajaú and Mearim Rivers presented solid suspended load higher than or equal to the Araguari River. Analyzing the mangroves in the estuaries we noticed the addition of mangroves along the estuaries of the Gurupi and Mearim rivers (Baia de São Marcos) and the reduction of mangrove areas in the Araguari estuary. The Amazon coastal zone is subject to natural processes of great magnitude, but atrophic activities influence the natural dynamics of the region by implementing unsustainable economic practices.
Acesso aberto (Open Access)
Análise integrada dos depósitos de caulim na região do Rio Capim: fácies, estratigrafia, petrografia e isótopos estáveis
(Universidade Federal do Pará, 2006-09-29) SANTOS JÚNIOR, Antonio Emídio de Araújo; ROSSETTI, Dilce de Fátima; http://lattes.cnpq.br/0307721738107549
The kaolin deposits that occur in the Rio Capim area, east of Cametá Sub-Basin, are inserted in the Ipixuna Formation. This unit distinguishs for presenting one of the largest worldwide kaolin concentrations of excellent quality to the cellulose industry. Beyond the economic character, a great volume of academic works focusing these kaolin deposits had led to pedological and geochemical approaches, but without taking into account their sedimentologic aspects, which are important to understand their genesis. Detailed sedimentologic and stratigraphic studies of the Rio Capim kaolin have been increasingly carried out in the last years, which led to the paleoenvironmental interpretations for the Ipixuna Formation, as well as to discuss better the mode of formation of the soft and semi-flint kaolin units that are typical of this unit. These works served to motivate the integration of sedimentologic and stratigraphic data with optical studies combined with hydrogen and oxygen isotope geochemistry in order to discuss the geologic processes involved in the origin and evolution of the soft and semi-flint kaolin units. The sedimentological analysis consisted in a more detailed facies description and stratigraphic analysis of newly open quarries that were not available during previous investigations. The additional exposures led to a better characterization of the lower kaolin unit, known as the “soft kaolin”, which is well stratified, favoring facies analysis. Hence, the soft kaolin unit consists of kaolinitized sandstones and kaolinitized pelites that were formed in tidally influenced fluvial channels (Facies Association A), tidal channel (Facies Association B), tidal flat/mangrove (Facies Association C), and tidal sand bar/tidal sandy flat (Facies Association D). These depositional environments are attributed to a tide-dominated estuarine system. Petrographic studies and scanning electronic microscopy (SEM) of the kaolin deposits in the study area had their composition was strongly modified after sedimentation. The soft kaolin consists of kaolinitized quartz sandstone and either laminated or massive pelites, which are composed by fragments of meta-volcanic lithic and volcanic felsic rocks, as well as metamorphic and granitics rocks. These lithologies were strongly modified during kaolinitization, as revealed by the intense replacement of the framework grains by kaolinite of three types, named herein as Ka, Kb and Kc kaolinites. Ka kaolinite occurs dominantly associated with kaolinitized sandstones, being characterized by pseudohexagonal crystals 10-30 μm in diameter, which are organized as booklets or vermicular forms that reach up to 400 μm in length. Kb kaolinite dominantes in the pelites, and consists of pseudohexagonal crystals 1-3 μm in diameter, occurring as isolated, face-to-face and parallel to pseudo-parallel crystals. Kc kaolinite forms pseudohexagonal to hexagonal crystals of 200 nm in diameter. It occurs dispersed through the soft unit, increasing significantly in abundance in association with paleosols at the top of the unit. The semi-flint kaolin deposits are constituted mainly of reworked grains derived from the underlying soft kaolin unit that are mixed with grains derived from metamorphic and granitic sources. These deposits are dominantly composed of Kc kaolinite that was formed during weathering. The deuterium (δD) and oxygen (δO) isotope analysis of the kaolin deposits from the study area helped to discuss better the evolution of the different types of kaolinites described above. Hence, the soft kaolin deposits display δO values varying between 6.04 ‰ and 19.18 ‰ in the Ka+Kb kaolinites, and between 15.38 ‰ and 24.86 ‰ in the Kc kaolinite. The δD values from this unit vary from – 63.06 ‰ to 79.46 ‰, and from –68.85‰ to -244.35‰ in the Ka+Kb and Kc kaolinites, respectively. The semi-flint kaolin deposits are characterized by δO and δD values ranging from 15.08‰ to 21.77‰, and from -71.31‰ to -87.37‰, respectively. Based on these data and on the isotopic composition of both meteoric and ground waters, it was possible to conclude that the kaolinites had not been formed in balance with modern weathering. These values represent the isotopic composition during the time of formation of the kaolinites, as well as mineralogical contamination of framework grains that are now replaced by kaolinites.
Acesso aberto (Open Access)
A aplicação da cromatografia gasosa acoplada (GC-FID), isótopos estáveis, palinologia e razão C:N na reconstituição paleoambiental de manguezais do Estado da Bahia e Espírito Santo.
(Universidade Federal do Pará, 2024-07-30) SILVA, Fernando Augusto Borges da; ALBERGARIA-BARBOSA, Ana Cecília Rizzatti de; http://lattes.cnpq.br/2666263256585897; FRANÇA, Marlon Carlos; http://lattes.cnpq.br/8225311897488790; https://orcid.org/0000-0002-3784-7702
Mangroves depend on ideal geomorphological, geochemical, and climatic factors to develop. Brazil, with its highly indented coastline under tropical and sub-tropical climate regimes, presents suitable conditions for the establishment of these ecosystems and distribution. The dynamics of these mangroves can be influenced by factors related to climatic variations and changes in hydrodynamic flow, resulting in modifications in sediment input and the origin of organic matter. These changes can be observed throughout the Holocene in different regions in of the country. On the northeast and southeast coast, the evolution of these ecosystems is associated with fluctuations in relative sea level (RSL) and sedimentary dynamics, while in the southern region, the change in the distribution of mangroves is a reflection of fluctuations in the RSL and climate changes caused by warming global. Recent studies seek to describe the evolution of these environments based on the elemental and isotopic characterization of organic matter. These constitute important tools in paleoenvironmental reconstruction. However, it is necessary to remember that the comparative analysis of the largest possible number of independent parameters is relevant as it adds value to the research and increases the reliability of the data to be analyzed, generating more precise information. Therefore, aiming to unravel the dynamics of organic matter in mangrove environments, as well as understanding movements of expansion and/or contraction of these ecosystems, analyzes of nalkanes were carried out using chromatography (GC-FID), associated with the sedimentary study, pollen data, isotopic and elemental analyses, synchronized with 14C and 210Pb dating, which allowed obtaining information about past biogeochemical processes and environmental changes during the Holocene and Anthropocene in the coastal plain at the mouth of the Itapicuru river (BA) and at the mouth of the Barra Seca and Jucu rivers (ES). Thus, the results of this research are presented in five scientific articles. The first, see chapter III, deals with the expansion of mangroves at the mouth of the Itapecuru river (BA) during the Anthropocene. The second scientific article (chapter IV) deals with the dynamics of mangroves at the mouth of the Barra Seca River, on the northern littoral of the State of Espírito Santo. The third article (chapter V) discusses the palynology tool used to understand the dynamics of coastal vegetation.The fourth article (chapter VI) presents the environmental changes that occurred at the mouth of the Jucu River, on the central coast of the State of Espírito Santo. Finally, the fifth article presents the results of n-alkanes analyses, compared with isotopic, elemental, palynological data, and 14C dating on the coastal plain of the Barra Seca River.
Acesso aberto (Open Access)
Aproveitamento dos resíduos cauliníticos das indústrias de beneficiamento de caulim da região amazônica como matéria-prima para fabricação de um material de construção (pozolanas)
(Universidade Federal do Pará, 2007-12-18) BARATA, Márcio Santos; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607; https://orcid.org/0000-0002-3026-5523
The Capim and Jarí regions are the most important kaolin district in the Amazon region, with the largest Brazilian reserves of high whiteness kaolin for paper coating products. Kaolin is obtained from three companies (IRCC, PPSA and CADAM) which produce annually around 1,000 M ton kaolinite-rich wastes derived mainly from the centrifugation phase of the process. The sludge is disposed on artificial sedimentary lakes covering large areas. Another type of kaolin waste is related to a non-processed iron-rich hard or flint kaolin, that overlays the so-called soft kaolin horizon (the main ore). These wastes exhibit appropriate characteristics for the production of high-reactivity metakaolin because they are extremely fine and composed of mainly by kaolinite. The main purpose of this work is to evaluate the feasibility of using these wastes as raw materials to produce mineral admixtures for OPC concretes. The wastes were firstly characterized for x-rays diffraction, thermal analysis, infrared spectroscopy, x-rays fluorescence and SEM. Three heating temperatures were evaluated: 750ºC, 850ºC and 900ºC, followed by pozzolanic activity tests based on traditional mechanical assays using Portland cement and hydrated lime mortars, and “Chapelle” test. The results showed that the more reactive pozzolans are those produced at temperatures that gave rise to higher LOI. The optimum burning temperature to produce metakaolinite from the hard kaolin was obtained at 750ºC while those from the Rio Jari and Rio Capim wastes were at 850ºC and 900ºC. The main reason is related to differences in the amounts of defects from three different wastes. The flint kaolin and Rio Jari waste are mainly composed by a “high-defect” kaolinite while the kaolinite from Rio Capim waste is a “lowdefect” kaolinite. In concrete test using different pozzolans those with metakaolin from wastes improved the mechanical and durability properties in comparasion to silica fume, a industrially manufactured metakaolin and reference concretes.
Acesso aberto (Open Access)
Arenito zeolítico com propriedades pozolânicas adicionadas ao cimento Portland
(Universidade Federal do Pará, 2011-08-29) PICANÇO, Marcelo de Souza; BARATA, Márcio Santos; http://lattes.cnpq.br/7450171369766897; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607
The proper use of pozzolans enables the production of special cements with lower manufacturing cost and higher durability in comparison with cements without mineral additions. It also enables significant gains in productivity and extending equipments life in the fabric, limestone reserves, and also helping in the reduction of CO2 release into the atmosphere. Zeolites have been used as pozzolanic material in mixtures with Fuller’s Earth and water in buildings from the ancient Roman Empire. Nowadays, there are many discussions involving pozzolanic reactivity of natural zeolites in the incorporation of Portland cement. In the Northeastern region of Brazil, sedimentary zeolites related to sandstones of the Parnaiba Basin wer discovered by the Geological Survey of Brazil in the 2000s. These sandstones are mainly composed by quartz, natural zeolites (estilbity) and clay (smectite). Preliminary studies have pointed that this sandstone may be used as pozzolanic material in Portland cements. The material must be previously sieved to remove quartz and thermally activated, since stilbite is a zeolite with low pozzolanic activity. The main objective of this work is to advance the understanding of the factors that govern the quality and performance of Portland cement modified with this zeolitic sandstone. For this work the structure was divided into three main stages, related to three specific objectives, so that the results are presented in the form of three scientific papers, described as follow: - Evaluation of the natural pozzolanic activity of the zeolitic sandstone to be used as mineral addition in the Portland cement. - The determination of which particle size provides the highest zeolite and smectite concentration, besides the calcination temperature that leads to a higer pozzolanic activity. - The establishing of the best amount of thermally activated zeolitic sandstone to be incorporated as a mineral addition in the Portland cement. During all phases, different instrumental techniques were used for the chemical and mineralogical characterization of the starting materials and products (sandstone + lime mortar, mortar with Portland cement + sandstone + Portland cement pastes sandstone), including: spectroscopy x-ray fluorescence, x-ray diffraction, thermal analysis and scanning electron microscopy. Heat-flow calorimetru assays were carried out to evaluate the physical properties, besides mechanical testing of compressive strength of cement mortars Porltand. In the first stage of the experimental program, the zeolitic sandstone was sieved into different granulometric fractions in order to remove the inert phases (quartz and other minerals), and concentrate the zeolite for further pozzolanic assays. In the second stage, after the first characterization of the samples, we used the zeolitic sandstone that passed in the # 200 and # 325 sieves and calcined at temperatures of 150º C, 300° C and 500° C. Finally, in the third stage, # 200 fraction was calcined at 500 ° C and mixed in different proportions (10, 20 and 30%) in the mortar. The results of the first stage, which culminated in the first article showed that the zeolitic sandstone accelerated the hydration of Portland cement due to the extreme fineness of the material. The sandstone showed pozzolanic activity, and estilbite is the main responsible for this behavior. However, the reactivity was slightly lower than the minimum required to be employed as pozzolan on an industrial scale. Additional studies are needed to ascertain if the thermal treatment between 400° C and 300o C could increase the pozzolanic activity of the sandstone due to the destruction of the crystalline structure of both estilbite and smectite. For the second stage, the results showed that the # 200 fraction was the most suitable because of the higher estilbite concentration (15%) in comparison to the # 325 ssample (2%). The calcination temperature of 500º C has provided the highest pozzolanic activity due to more effective destruction of the crystalline structure of both estilbite and smectite. More moderate temperatures of 150° C and 300° C were not enough. Mortars with the 200 # sample calcined at 500 ° C reached values smaller as those required for a material to be considered as a pozzolane, in this case, 6 MPa for mortar of lime and 75% for the pozzolanic activity index (IAP). The results showed from the third stage showed that the AZ2-3 mixture (10% of zeolitic sandstone incorporated in Portland cement type CPI-S), showed the best result of compressive strength and mineralogical properties of the samples suitable for the production a commercial cement type CPII-Z. In general, one concludes that the zeolitic sandstone from northeastern Brazil has the potential feasibility of producing a CPII-Z cement, whose pozolan contents ranges from 6 to 14% in the Portland cement, according to the ABNT - NBR 11578. Although the strength of the mortar with 10% of AZ2- 3 has reached resistance values close to the reference mortar with 100% of CPI-S, further studies should be carried out in order to find better proportion of sandstone and to meet the requirements for future commercialization.
Acesso aberto (Open Access)
Aspecto tectôno-sedimentares do fanerozóico do nordeste do estado do Pará e noroeste do Maranhão, Brasil
(Universidade Federal do Pará, 1992-09-16) IGREJA, Hailton Luiz Siqueira da; FARIA JUNIOR, Luis Ercílio do Carmo; http://lattes.cnpq.br/2860327600518536
A synthesis of the tectono-sedimentary evolution of the Phanerozoic at Northeastern Pará and Northwestern Maranhão is discussed with enphasis to the Bragança-Viseu and São Luis basins. This research is based on field observations, gravity (Bouguer Anomalies), magnetic, seismic, and borehole data interpretations. Five sedimentary sequences are defined: 1) Piriá-Camiranga (Cambrian-Ordovician to Silurian), 2) Lower Itapecuru (Lower Cretaceous), 3) Upper Itapecuru (Upper Cretaceous), 4) Pirabas-Barreiras (Oligocene-Mioceneto Pliocene) and 5) Pará (Quaternarg). The regional basement is an igneous-metamorphic assemblage which outcrops in two windows. The sedimentary and structural features of the Piriá-Camiranga sequence are consistent with a tectono-sedimentary model of coastal environment with fluvio-glacial influence related to a tilted blocks system induced by strike-slip motion. This sequence represents an evolutive stage coincident to the Eo-Hercynian paroxysm (Paleozoic) which ended with the closure of the Atlantic I (first geotectonic cycle of the Gondwana). The Lower and Upper Itapecuru, as well as the Pirabas-Barreiras and Pará sequences, are related to the Equatorial Atlantic opening during the Mesozoic and Cenozoic times. They are analysed by severa), authors which reached the interpretations refered to as Models of: Fracture Zones; Anti-clockwise rotation of Africa; Intumescence and fracturing; Clockwise rotation of the South America Nate; and Wrench Tectonics. These models were experimented for the studied area. The time and environments of the sedimentary processes are related to the rift and pos-rift phases of the equatorial coastal basins, but these models were not adequate to explain the structural features. A new model is proposed to explain the origin and development of the basins taking into account a regional NE-SW extension axis and formation of the Bragança-Viseu and São Luís basins with similar polarities. The tectono-sedimentary map for the Phanerozoic of the Northeastern Pará / Northwestern Maranhão enhances the compatibility of the depositional and tectonics systems with two periods of oceanic opening of the Northern Gondwana border.
Acesso aberto (Open Access)
Aspectos lito-estruturais e evolução crustal da região centro-oeste de Goiás
(Universidade Federal do Pará, 1985-11-13) COSTA, João Batista Sena; VILLAS, Raimundo Netuno Nobre; http://lattes.cnpq.br/1406458719432983; HASUI, Yociteru; http://lattes.cnpq.br/3392176511494801
The study area is bounded by the cities Paraíso do Norte, Gurupi, and Dianópolis in north-central Goiás State. The area contains diverse lithostratigraphic units and various generations of structures related to distinct thermo-tectonic events. Based on the distribution and the petrographic and structural characteristics of the ancient rock assemblage, four litho-structural domains were defined and attributed to the Archean. Domain "1" includes the region of Almas-Dianópolis and is interpreted as part of granite-greenstone terrane. It includes a group of tonalitic gneisses with associated supracrustal rocks (Goiano Complex), a sequence of metavolcanic rocks and metasediments (Riachão do Ouro Group), and various tonalite bodies (Serra do Boqueirão Suite) intruded into the earlier units. The evolution of the domain includes three principal deformational events: a) Formation of the amphibolites and/or biotite gneisses and granitoids characterized by sub-vertical banding oriented N10ºE and accompanied by mineralogical changes under conditions of amphibolite facies; b) deposition of the Riachão do Ouro Group, followed by isoclinal folding oriented N10°E and consequent transformation to greenschist facies. The emplacement of the tonalitic diapirs of the Serra do Boqueirão Suite is related to this event; c) a foliation gently inclined to the SE resulting from a simple low-angle ductile-brittle shearing process which affected the west part of this domain, transforming the rocks of the Goiano Complex into mylonitic gneisses under amphibolite facies conditions. Domain 2 includes the counties of Porto Nacional, Brejinho de Nazaré, and Natividade in the east-central part of the area. It is characterized by granulitic gneisses (Porto Nacional Complex), by tonalitic gneisses with associated supracrustal rocks (Manoel Alves Complex), including metasediments and metavolcanics (Morro do Aquiles Formation), and by pegmatitic granites such as the Xobó Suite. The different lithologic units take the form of lenses or sub-horizontal concordant to sub-concordant bodies with strike N30°E. They show structural features produced by a low-angle ductile-brittle shearing process under amphibolite facies conditions. Superposed on the low-angle features are various zones of high-angle directional shear having different intensities of deformation, but all in greenschist facies conditions. Domain 3 is within the NW part of Paraiso do Norte county and is interpreted as a granite-greenstone terrane similar to that of Domain 1. This Domain includes the Colméia Complex, the Rio do Coco Group, and the alkaline gneisses of Monte Santo. Two principal deformational phases are responsible for the structures in this domain: a) folding (S) of the gneissic granitoids of the Colméia Complex into recumbent folds oriented E-W. The axial plane schistosity (S1) formed in medium to amphibolite facies conditions; b) deposition of the Rio do Coco Group, discordant with the Colméia Complex, followed by sub-vertical folding oriented E-W. The second generation of folds in the Colméia Complex is related to this deformational event. Domain 4, in the west-central part of the area, includes parts of Paraíso do Norte, Fatima, Gurupi, and Porto Nacional counties. This domain is composed of the Rio dos Mangues Complex, the Matança and Serrote Suites, and the alcaline gneisses of the Serra da Estrela, distributed in sub-concordant sheets oriented N30°E. Similarly to that observed in Domain 2, these rock assemblages show structural features related to low-and high-angle shearing events. The transition between Domains 1 and 2 and between Domains 3 and 4 is gradational, such that two ancient blocks of crust are defined (Domains 1+2 and 3+4] separated by a belt of granulitic rocks (Porto Nacional Complex). The zone of juxtaposition corresponda to a belt of low-angle ductile shearing developed by the overthrusting of the Brazilian block, on the east, onto the Araguacema block to the west. Similar geologic conditions have been well characterized in South Africa, in western Greenland, and in NW Scotland and are beginning to be described in various regions in Brazil, constituting a new way to understand the relations between Archean terranes. Granite bodies of the Lajeado Suite at the end of the Lower Proterozoic and ultrabasic bodies in the first half of the Middle Proterozoic were injected into this crustal segment stabilized at the end of the Archean. During this epoch the Transbrazilian Lineament became defined as a brittle shear zone. Basins were developed in the second half of the Middle Proterozoic, with deposition of the Baixo Araguaia Supergroup and the Natividade Group. These two are separated today by a block limited by the cities of Paraíso do Norte, Gurupi, and Porto Nacional. The Transbrazilian Lineament was reactivated in this period.At the end of the Middle Proterozoic an E-W regional compression produced the Araguaia and Uruaçu fold belts. The evolution of the Araguaia fold belt involved four stages of structural deformation. In the first stage, N-S recumbent folds were formed having axial plane schistosity (S1) developed in intermediate amphibolite facies to intermediate greenschist facies conditions. The intermediary stages involved folding and refolding of the S1. The last stage is related to the formation of domai structures resulting from the intrusion of the granite bodies of the Santa Luzia Suite. As a result of this evolution, the Araguaia belt has an importent asymmetry characterized by intensification of deformation and mineralogical transformations from west to east. The Uruaçu fold belt is In general characterized by folds with variably-oriented axial planes and mineralogical changes tipical of greenschist facies. In the studied region, regular variations In deformational intensity and metamorphic degree were not found. The immature sediments of the Monte do Carmo Formation are the products of the last lithogenetic processes of the Middle Proterozoic in the area. During the evolution of the Araguaia and Uruaçu fold belts, the north part of the Goiano massif had a limited participation in such a way that it functioned as a rigid block with respect to the folding on either side. The final products related to the polycyclic evolution of this crustal segment during the Priecambrian are represented by directional fault systems oriented principally N40º -60ºE and N40º -50º W. The NE system of faults reflects a reactivation of the Transbrazilian Lineament in the Upper Proterozoic. Thick sedimentary sequences were deposited in the Phanerozoic and new movements on the Transbrazilian Lineament caused the development of important block faulting which is reflected in part by the present-day geomorphology of the area.
Acesso aberto (Open Access)
Avaliação ambiental dos recursos hídricos, solos e sedimentos na área de abrangência do depósito de resíduos sólidos do Aurá - Belém-PA
(Universidade Federal do Pará, 2002-03-27) PIRATOBA MORALES, Gundisalvo; FENZL, Norbert; http://lattes.cnpq.br/6834981018643186
With 1.754.099 inhabitants, the municipality of Belém produces roughly 1,200 tons per day of all kinds of waste, which are deposited in a landfill known as Lixão do Aurá, bordering the municipality of Ananindeua. During the past 11 years, this area has been accumulating approximately three million and two-hundred thousand tons of solid waste, transforming that place into a permanent local source of anthropogenic pollution, altering environmental conditions and resources around the whole area surrounding it. A Vertical Electrical Resistivity Sounding (VERS) procedure, conducted in the area before it was transformed into the landfill (1991), compared with the measures taken eight years later (1998), show that the land resistance has considerably dropped, with values in some cases — 109 times smaller than the original ones, thus indicating that the layers have been affected by the leach from waste decay. Fifteen profiles were conducted in the area, using the electrical imaging system, allowing us to confirm the (VERS) results, with evidences that the underground water has been affected by the infiltration and by the leachate vertical and horizontal movements. The hydro geological characteristics in the area show that the local predominant type of aquifer is of the free kind, locally confined, with hydraulic gradient of approximately 0.695%, effective porosity of 28%, permeability coefficient ranging from 1.1 x 10-3 to 0.9 x 10-4 cm/s, and underground flows running north/south towards the Guamá River, at approximately 14.79 m/year. A multivariate statistical analysis has shown that superficial water samples, collected simultaneously at three control points, during one tide cycle, regardless of the season, portray totaily different behaviors, indicating that superficial water resources are being affected by the superficial movement of leachate. With the concentration value figures for each of the leachate parameters (pH, conductivity, alkalinity, ammonia, total organic carbon, chloride, sodium, potassium, calcium, and magnesia), plus the flow of the Aurá River at the control point near the Guamá River, it is possible to estimate the quantity of pollutants that the solid waste landfill sends into the water system. During one tide cycle, in the dry season, the solid waste landfill deposits approximately 13,115 kg of chloride, 417 kg of ammonia, and 129,767 kg of salts in the local water system. For the underground waters, the multivariate statistics showed that the samples collected In the monitoring wells in the area show significant differences, indicating that the wells located downstream have been affected by the leachate. The presence of sand layers right in the area where solid waste is deposited allows for the vertical and horizontal movement of the different pollutants originated by the leachate. The heavy metais anaiyses, conducted under the sequential extraction methodology, showed percentages in the geochemical phases potentially bio-available in the studied soil and sediment samples. In the soil samples, the potentially bio-available fraction (replace, reduce, and organic geochemistry phases) contained an average of 32% of the total Cadmium (Cd), 11.8% of the total Chromium (Cr), 23% of the total Copper (Cu), 12.32% of the total Nickel (Ni), 43.1% of the total Lead (Pb), and 31.01% of the total Zinc. The potentially bio-available phases percentage in the sediments of the area was greater than the ones found in the soil samples. In these sediments, the quantity of heavy metais in the potentially bio-available fraction, shown higher values during the dry season than during the rainy season; for instance, 33% of the total Cd measured during the rainy season increased to 37% in the dry season; Pb increased from 61 to 70%; Zn, from 51 to 54%, among others. The metais analyzed by total attack in the soil samples, compared with the sandstone backgrounds, indicate that the Fe (3.1%), Cu (18.5 ppm), Ni (10.1 ppm), Pb (69.5 ppm), Cr (76 ppm), and Cd (>1 ppm) are above normal standards. In the case of sediment samples, the EPA background values (total concentration) would be moderately polluted by Cr (average 64.6 ppm) and heavily polluted by Fe (3.8%) and Mn (600 ppm). These results show that the sediments were not polluted by Pb and Zn. Considering the potentially bio-available phase and using the tool provided by a Geographic Information System (GIS), we can say that, during the rainy season, the sediment samples were not polluted by Cr (potentially bio-available fraction smaller than 20% of the total) were highly polluted by Pb and Zn (PBD higher than 50%), and moderately polluted by Cu, Ni, and Cd (PBD between 20 and 50%).
Acesso aberto (Open Access)
Biogeoquímica dos sedimentos lamosos e sua influência no padrão de distribuição da vegetação, no manguezal de Bragança, NE do Pará.
(Universidade Federal do Pará, 2009-10-30) CRUZ, Cleise Cordeiro da; LARA, Rubén José; http://lattes.cnpq.br/8695520453124286; 8695520453124286
The present study investigates the relationship between sediment-plant and biogeochemical processes involved in the development and spatial distribution of vegetation in the Bragança mangrove peninsula, exposed to macrotidal regime (spring range 4 m). Therefore, three transects were established at three different topographic levels of that peninsula being colonized by different patterns of vegetation: Transect 1 (T1) Transect 2 (T2) and herbaceous plateau (PHb). The vegetation in T1 is composed mainly by Rhizophora mangle and Avicennia germinans and it is situated in a semi-diurnal flooding regime forest. The transect T2 is less frequently flooded and is characterized by a stand of young Avicennia trees and herbaceous vegetation. In the highest part of this transect with low inundation frequency and high salt stress, the vegetation is dominated by shrubs of A. schaueriana coexisting with herbaceous vegetation of Sesuvium portulacastrum and Sporobolus virginicus. The PHB, localized in the zone with lowest inundation frequency is colonized mainly by tree species of A. schaueriana in the form of shrubs and S. portulacastrum and S. virginicus with sporadic presence of B. maritima. In these sites were performed measurements of the flooding frequency; floristic and fitossociologic inventory in mangrove forest and in the herbaceous halophyte vegetation. Also sediment cores (0-30 cm) and vegetation (leaves, stems and roots) were collected. The sediment samples were subjected to granulometrical, mineralogical and chemical (total sample) analyses, and determination of the humidity, organic matter and salinity as well as cation exchange capacity (CEC) besides determination of the total, inorganic, organic and bioavailable phosphorus. In the vegetation samples, chemical analysis of total phosphorus was performed. The variance analysis (ANOVA) One Way (Post Hoc Fisher's test) was applied to test the mean of the variables (humidity, salinity, organic matter, total-P, inorg.-P, org.-P and bioavailable-P. Discriminant analysis was used to measure the degree of influence of environmental variables (humidity, salinity, organic matter and total-P) in the discrimination of sites sampled. The correlation analysis of Pearson was used to evaluate the degree of interaction between discriminated variables with the hydrological conditions and forest structure data. Fine sediments (clay) in T1 and T2 suggest areas of slow deposition, while in the plateau high levels of sand suggest its formation on a paleodune with intense eolic reworking of sandy and tidal input of finer sediments. The main mineralogy of the sediments is composed of quartz (dominant in the sand and silt) and clay minerals: kaolinite and illite, other minerals of authigenic origin are pyrite, jarosite and vivianite and possibly smectite and k-feldspar. The main mineralogical and chemical composition of major and trace elements indicate the influence of sediments and soils of the Barreiras Formation on the genesis of sediments mangroves and marine influence in their chemical composition. In T1 (the more flooded sector), the dominant species is R. Mangle, while in T2 (less flooded zone) the Avicennia genus is predominant. In the herbaceous plateau the dominance of the S. portulacastrum species, is five times higher than that of S. virginicus, indicating that Sesuvium has greater ability to survive in environments with salt stress. The flooding gradient results in highly significant positive correlation with humidity. This trend is reflected in the tree height, volume and basal area correlated significantly with sediment phosphorus availability in T1 and CEC in T2. The results of Discriminant Analysis show that in T1 the humidity is the variable that most contributes in the discrimination of (Rhizophora and Mixed) forest of the Avicennia forest, while organic matter (OM) discriminated the Mixed forests and Rhizophora forests. In T2, the humidity, total-P and salinity are the variables that most contribute to the discrimination of sites in this transect. In the profiles, along the plain, the total-P and organic mater were the most important variables for discrimination of T1, T2 and PHb. The distribution of vegetation reflects different ecophysiological responses to environmental gradients. Therefore, the combination of organic matter, salinity, and phosphorus and, the high cation exchange capacity of sediments represent a significant role in the colonization of vegetation in the peninsula of Bragança.
Acesso aberto (Open Access)
Caracterização geomorfológica estratigráfica e geoquímica da Planície Costeira do município de Itarema-CE.
(Universidade Federal do Pará, 2011-09-01) PEREIRA, Lamarka Lopes; FREIRE, Geoerge Satander Sá; http://lattes.cnpq.br/6803944360256138; 6803944360256138; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429; 5707365981163429
The Itarema coastal plain, situated at the western coast of Ceará, in the area dominated by the Cenozoic sedimentary cover. This thesis shows the geomorphological, sedimentological and geochemical features of this coastal plain. The Itarema coastal plain is subdivided in two major morpho-structural units: pre-coastal ¨plateaus¨ and coastal plain, that is subdivided into lithostratigraphic units, lagoon plain, tidal plain with and without mangroves, marine and fluvial plain, mobile and fixed dunes, beach ridges, tidal channels, sand bars and beaches. The supply and sediment transport in the area are closely linked to the climatic, meteorological and oceanographic conditions. The sedimentary, stratigraphy, geomorphological and geochemical data have been defined: (1) five lithological units: Lagoon Deposits, dune deposits, eolianits deposits, beach deposits and alluvial deposits and (2) seven lithofacies: mud sandy, mud, Sand mud, fine sand, medium sand, thick sand, conglomeratic sand-clay with different characteristics which have been drawn through the lateral and vertical correlations, thus allowing the interpretation of depositional paleoenvironments related to the evolution of the Itarema Coastal Plain. The analysis of the lithological units allowed the reconstruction of the processes indicative of a transgressive sucession prograded during which the lagoon-barrier system was installed on the system of alluvial fans, the bus of small streams, forming the lagoon plain, it was also noted that the lagoon has undergone changes in their size both by progradation of the barrier and subsequently by the deposition of sediments within the same wind. The Itarema coastal plain presents physiographic features of an coastal promontory or embaiments of central nuclei as a spiral, that would have provided the evolution to the current environment and the current model of coastline with beaches of the barrier beach-type and suggests that is occurring repetition in the construction of comparative morphology morphogenetic active in the region's past.
Acesso aberto (Open Access)
Caulim calcinado: estudo cinético da dissolução do alumínio em meio ácido e aplicação como precursor na produção de sílica porosa
(Universidade Federal do Pará, 2016-12-19) LIMA, Paula Elissa Antonio de; NEVES, Roberto de Freitas; http://lattes.cnpq.br/9559386620588673
A kinetic study of metakaolin (calcined kaolin) dissolution was carried out using kaolin for paper coating derived from the Rio Capim region (Pará State, Northern Brazil). The kaolin was calcined at 700ºC for 2 hours, in order to obtain metakaolin, and then leached with sulfuric, hydrochloric and nitric acid at 95ºC, 80ºC and 70ºC ± 3°C. The leachings were performed using excess acid of 5%. Samples were collected every 15 minutes for 3 hours and subjected to aluminum analysis by the EDTA titrimetric method. Final aluminum extraction of 97.42%, 97.99% and 95.9% was obtained with sulfuric, hydrochloric and nitric acid, respectively. Hydrochloric acid was faster than nitric and sulfuric acid, which showed a similar dissolution behavior. Kinetic models of homogeneous (Integral Method, Method of Half-Lives and Method of Initial Rates) and heterogeneous (Shrinking Core Model) reaction were used. The Shrinking Core Model for spherical morphology with a constant size showed better fit. The leaching process is chemically controlled, with leaching reaction of the first order with respect to aluminum from metakaolin, the first order with respect to sulfuric, hydrochloric and nitric acid concentration and activation energies of 87.78 kJ/mol, 90.60 kJ/mol and 91.58 kJ/mol, respectively. Previous research, using excess acid above 50%, are consistent with the data found in this study carried out with only 5% excess acid. The study about the application of calcined kaolin as a precursor in the porous silica production was carried out with the solid obtained in the leaching process with sulfuric acid. The leached material was a microporous solid, with 86.7% of silica, high specific area (297.13m²/g) and humidity adsorption capacity compatible with commercial silica.
Acesso aberto (Open Access)
Desenvolvimento da vegetação e morfologia da foz do Amazonas-PA e rio Doce-ES durante o Quaternário tardio
(Universidade Federal do Pará, 2013-11-05) FRANÇA, Marlon Carlos; PESSENDA, Luiz Carlos Ruiz; http://lattes.cnpq.br/0425441943533975; COHEN, Marcelo Cancela Lisboa; http://lattes.cnpq.br/8809787145146228
This work compares the vegetation and morphological changes occurred along the littoral of the Marajó Island, Amazonian littoral, and the coastal plain of the Rio Doce, southeastern Brazil, during the Holocene and late Pleistocene/Holocene, respectively, focused specifically on the response of mangroves to sea-level fluctuations and climate change, which have been identified in several studies along the Brazilian coast. This integrated approach combined radiocarbon dating, description of sedimentary features, pollen data, and organic geochemical indicators (δ13C, δ1₵N and C/N). On coastal plain of the Doce River between ~47,500 and ~29,400 cal yr BP, a deltaic system was developed in response mainly to sea-level fall. The post-glacial sea-level rise caused a marine incursion with invasion of embayed coast and broad valleys, and it favored the evolution of a lagoonal/estuary system with wide tidal mud flats occupied by mangroves between at least ~7400 and ~5100 cal yr BP. Considering the Marajó Island during the early and middle Holocene (~7500 and ~3200 cal yr BP) mangrove area increased over tidal mud flats with accumulation of estuarine/marine organic matter. It was a consequence of the marine incursion caused by post-glacial sea-level rise, further driven by tectonic subsidence. Dry conditions in the Amazon region during this time led to a rise is tidal water salinity and contributed to mangrove expansion. Therefore the effect of relative sea-level (RSL) rise was determinant to the mangrove establishment in the southeastern and northern region. During the late Holocene (~3050 – 1880 cal yr BP) the mangroves in both regions were retracted to a small area, with some areas replaced by freshwater vegetation. This was caused by the increase in river discharge associated to a wet period recorded in the Amazon region, and considering the coastal plain of the Doce River (southeastern Brazil), the mangroves shrank in response to an increase in fluvial sediment input associated to a sea-level fall.
Acesso aberto (Open Access)
Desenvolvimento de processo para obtenção de zeólita do tipo faujasita a partir de caulim de enchimento, caulim duro e tube press: aplicação como adsorvente.
(Universidade Federal do Pará, 2015-03-31) ROCHA JUNIOR, Carlos Augusto Ferreira da; NEVES, Roberto de Freitas; http://lattes.cnpq.br/9559386620588673; 9559386620588673
The main purpose of this work is zeolite synthesis of faujasite type (X and Y) from kaolin from the beneficiation process for paper coating, hard kaolin or Flint (mining of waste), tube press kaolin and filler kaolin. For each process zeolitização kaolin used in a chemical reactor a product of calcination of each material (metakaolin), sodium metasilicate, solid sodium hydroxide and distilled water, subjected at 110 ° C, reaction time 13 h Si / Al ratio of 2, 4 and 6. The products of each zeolite synthesis as well as the starting kaolin were characterized by chemical, physical and mineralogical analyzes such as X-ray diffraction, X-ray fluorescence, electron microscopy scan and thermal analysis. From these tests, it was observed that all the kaolin showed the formation of faujasite zeolite, but with differences in the peak intensities and their associations with other zeolite phases. Hard kaolin showed a lower potential zeolitization into the Si / Al ratio equal to 2 compared with the other two supposedly related to the iron present in its composition, thus made was a removal process of this constituent, by Mehra and Jackson method to verify a possible maximization in the synthesis process. New results indicated a complete modifications to the area and degree of structural order of faujasita phase, now moving into a major phase and there is an increase in the degree of structural order. As this reaction condition for consumption and a lower cost of raw materials and energy for calcination This medium was used as a starting point for an experimental design to evaluate the best reaction conditions. This design was varied some parameters of the synthesis as temperature, reaction time, Si / Al ratio and H2O / Na2O. The results of the statistical design showed the formation of faujasite in 32 points of study, as well as a great region with 8 points of planning, in this region point 13 proved the best reaction conditions. The zeolite synthesized at this point, showed an increase of ammonium adsorption capacity and percentage near 85 % efficiency up to 60 ppm. The Langmuir model was more suitable than the Freundlich and Sips in agreement with experimental data. The thermodynamic parameters showed that adsorption of NH4 + is a spontaneous and exothermic process, in which the temperature rise from 25 to 60 ° C promotes a small decrease in the adsorption capacity.
Acesso aberto (Open Access)
Desenvolvimento do processo de síntese da zeólita A e da sodalita a partir de rejeitos de Caulim da Amazônia com aplicações em adsorção
(Universidade Federal do Pará, 2011-08-31) MAIA, Ana Áurea Barreto; POLMANN, Herbert; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607; 7501959623721607
The minimization of industrial and domestic residues is one of the great challenges that human kind is facing. Several proposals are released for this intention, ranging from improving industrial processes in order to minimize waste generation, besides their use in the production of new materials. In this context, this work has the main purpose of using kaolin residues from industries located in the Pará State, northern Brazil, for the production of zeolites (e.g., zeolite A and sodalite). These companies exploit kaolin from the world famous Capim and Jari regions and produce high quality kaolin for the paper industry. Preliminary mineralogical and chemical characterization of the Capim (KC) and Jari (KJ) kaolin residues was carried out as the basis for further zeolite A and sodalite synthesis. The study of thermal activation of kaolinite at various temperatures was carried out using 27Al and 29Si magic angle spinning nuclear magnetic resonance (MAS NMR), in order to to produce highly reactive metakaolinite from KC and KJ residues. The zeolite NaA synthesis was performed for varying parameters such as time and Na/Al relation. Temperature was kept constant at 110 °C for the two starting materials (KC and KJ). The KA, MgA and CaA phases were prepared by ionic exchange from phase NaA. In the sodalite synthesis, kaolinite was used directly as starting material and two temperatures (150 and 200 °C) were utilized. The Na/anion and Na/Al relations were maintained constant and varied, respectively in the reaction mixture for KC and KJ. The removal performance of mixed metal ions (Co2+, Cr3+, Cu2+, Zn2+ e Ni2+) in aqueous solution was investigated by adsorption process on zeolite NaA prepared from KC an KJ as proposal to reduce environmental problem with industrial wastewater streams that contain heavy metals. The XRD results showed that the residues are mainly composed of kaolinite with extremely low impurity level. For comparing the residues from two regions, Capim and Jari verified that the KC displays a high degree of structural order. This difference displays significant influence in the ideal heating temperature to produce a material with high amount of 4-coordinated A1. As a result, the ideal temperature to produce highly reactive metakaolinite is: 600 °C for Jari kaolin residue and 700 °C for Capim kaolin residue. Zeolite A was produced with a large degree of structural order and was generally obtained as the only zeolitic product. The following synthesis conditions were used: Na/Al ratio of 1.64 and time 18 and 20 h for KC and KJ, respectively. The cationic exchange process between Na from zeolite A and K, Mg and Ca in solutions displays efficient result and with XRD data, was verified that the KA, MgA and CaA phases were obtained with success. The sodalite series was produced from KC and KJ and by FTIR was confirmed the chloride, sulphate and carbonate insertion in its structure. The KJ kaolinite displays high reactivated in the sodalite synthesis, it could be explicated by its low degree of structural order. The sorption capacity of heavy metals mixture (Co2+, Cr3+, Cu2+, Zn2+ e Ni2+) on zeolite NaA, produced from KC and KJ, display satisfactory values. The results revealed that the Langmuir model is more appropriate than Freundlich in the fit of the experimental data. Zeolite A, produced from residues (KC and KJ), could be excellent materials for the treatment of wastewater.
Acesso aberto (Open Access)
Desenvolvimento metodológico e avaliação de contaminação por HPAs em sedimentos da baia de Guajará
(Universidade Federal do Pará, 2014-03-31) SODRÉ, Silvana do Socorro Veloso; CAVALCANTE, Rivelino Martins; http://lattes.cnpq.br/2253127527012522; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568
Polycyclic Aromatic Hydrocarbons (PAHs) are pollutants with toxic effects, harmful to the environment and to human health. They are part of a group of persistent organic pollutants (POPs), which by its characteristics have an impact on the environment and are extensively studied for this reason. They may be present in particulate, dissolved and/or gaseous forms, in different environments such as soil, sediment, air, water, particulate matter in the atmosphere, organisms and food (Kennish, 2007). Natural sources of PAHs include volcanic activity, natural fires, oil oozing and biogenic processes. Anthropogenic PAH pollution may occur by incomplete oil combustion (automotive and industrial), intentional burning of wood and plantations, domestic and/or industrial wastewater, urban water flow, accidental spills of oil and derivatives. Hydrophobic and lipophilic, these substances can be easily adsorbed by sediments, so that this matter is an important reservoir for them. To evaluate the presence of these compounds in the environment, this work used High Performance Liquid Chromatography. The samples used in the development and optimization of the methodology were collected in the Guajará bay (Belém - PA). This work consisted in the development of a methodological procedure (with adaptations and optimizations) to quantify 16 PAHs in 10 points in the Guajará bay in two field campaigns, so that 20 samples were analysed. In the development stage of the analytical method, elution systems, system polarity and eluent flow were tested, among others. In order to validate the method, the following parameters were assessed: fidelity, linearity, detection limit and quantification limit. Diagnostic ratios were calculated to identify the primary sources of PAHs found in the bay. The primary sources of the 16 PAHs studied in the sediments of the bay were identified based on ΣPAHs BMM/ΣPAHsAMM; Phe/Ant; Flt/Pyr; Ant/Σ178; Flt/Σ202; B(a)P/Σ228 and Ind(123cd)pyrene/Σ276. In the first field campaign, the total concentration of light PAHs ranged from 132.3 ng.g-1 to 1704.14 ng.g-1, the ΣPAHs of the heavy ones, from 125.82 ng.g-1 to 1269.71 ng.g-1 and the total ΣPAHs, from 317.84 ng.g-1 to 3117.06 ng.g-1. In the second field campaign, the total concentration of light PAHs ranged from 76.12 ng.g-1 to 1572.80 ng.g-1, the ΣPAHs of the heavy ones, from 213.90 ng.g-1 to 1423.03 ng.g-1, and the total ΣPAHs, from 290.02 ng.g-1 to 2995.82 ng.g-1. Based on these results, the Guajará bay can be classified as moderately impacted. The combustion is the predominant source of PAHs in the sediments of the bay, followed by vegetal biomass combustion and by the contribution of oil and supplies. Most of the points studied in this work, during the two field campaigns, showed concentrations of individual PAHs above the SQGs.
Acesso aberto (Open Access)
Detecção de mudança e sedimentação no estuário do Rio Coreaú
(Universidade Federal do Pará, 2014-09-02) RODRIGUES, Suzan Waleska Pequeno; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
The use of new techniques to study the evolution and filling incised valleys has provided, over the years, important results was to understand how the coastal evolution of the Brazilian coastal zone. In this context, this thesis aimed to study the evolution of the estuary Coreaú River, located in the state of Ceará, in different time scales, is "Possible" (months, years), "Engineering" (years, decades) and "Geology" (hundreds, centuries, millennio), proposed by Cowell et al (2003), with the goal to assess whether changes /alterations over the years were significant or not in the estuary. As a result, we obtained the first goal, using remote sensing techniques from image sensor TM, ETM+ and OLI of Landsat 5, 7 and 8 and sensor LISS-3 of satellite ResourceSat-1 from 1985 to 2013, a change minimal in relation to morphological changes along the estuary in the last 28 years (between Possible scales and Engineering), there was an increase in this period of 0.236 km2 (3%) of the area, not bringing significant changes to the estuary. Regarding sedimentation rate, corresponding to the second goal, from the collection of nine witnesses, up to 1m deep and using radionuclídeo 210 Pb along the estuary, we obtained a rate that ranged from 0,33 cm/year 1 cm/year (between scales Geological and Engineering) near the mouth of the estuary, and with a quick sedimentation perceived on the east bank of the river, where there are younger sediments toward the west margin. Regarding the fulfillment, third and final goal from the sampling of testimonials to 18 m depth, using the sampler Rammkernsonden (RKS), profiles and stratigraphic sections that helped understand filling the valley section of the estuary of the Coreaú river were generated and that it is a fluvialmarine estuary, filling the valleys formed in group Barriers in the last 10.000 years before present. These analyzes and results serve as a basis for comparison with other estuaries, either fluvial, fluvio-marine or marine, to better understand what the possible events that dominated sedimentation along the coast of Brazil at diferent scales.
Acesso aberto (Open Access)
Dinâmica da paisagem na porção norte da Ilha do Bananal-TO e adjacências ao longo do Quaternário tardio.
(Universidade Federal do Pará, 2019-08-30) MENDES, Laís Aguiar da Silva; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302
Paleoclimatic and paleoenvironmental studies aim to understand processes of global landscapes evolution, contributing to the reconstitution of the quaternary landscapes and the climatic and environmental changes to which were submitted during this period of the earth's geological history. Some studies in the Amazon, but especially those led in regions more sensitive, such as ecotones and wetlands, show that these areas underwent various paleoecological changes during the Pleistocene and Holocene. The present study was led in the Bananal Island region located in a transition area between the Amazon and Cerrado biomes. The Bananal Island, considered by many authors the largest river island in the world, occupies an area of about 20,000 km2 and is located between the middle course of the Araguaia River and its tributary by the right branch, the Javaés River, in the state of Tocantins. The northern portion of the island stands out for its complex mosaic of geomorphological features (marginal dikes, abandoned meanders, paleochannels and lakes) and contrasting geobotanical features (forests and savannas), such that reflect the intense hydrodynamic activity in this region. Seasonally it is flooded by rainwater and rising water table, so it is considered a seasonal wetland. The aim of this work is to understand the dynamics of this landscape, based on the mineralogical and chemical composition of soils and sediments and the palynological composition study of lacustrine sediments of this region. Therefore, samples of ravines exposed on the banks of Javaés and Araguaia rivers, sandy bars and lake sediments were collected. Soils and sediments were analyzed for their mineralogy by X-ray diffraction and chemistry by ICP-AES and ICPMS. The sediment cores collected in 2 distinct lakes, one located in the interior of the northern portion of Bananal Island (Quatro Veados Lake) and the other located on the surroundings of the Javaés River (Mata Verde Lake) were analyzed for their palynological content and dated by AMS 14C. The results of this research are presented in 3 articles: the first one treaties about the mineralogy and geochemistry of the soils and sediments of Bananal Island, the bars and ravines along the Javaés River. Therefore, it discusses about the diversified nature of the minerals and chemical elements that the strata and horizons of these surface covers are composed, pointing to geological provenance, as well as the geochemical processes involved in the current and past dynamics of this landscape. The second article presents the dynamics of vegetation over the last 2000 years AP in the interior of Bananal Island and discusses its relationship with local climatic and edaphic conditions. The third article, on the other hand, describes the vegetational succession occurred in the last 400 years AP, based on the pollen record of sediments from a lake located on the Bananal Island surrounds, and analyzes the modern pollen spectrum in the region. The results obtained through this work present a highly diversified landscape in terms of its geoforms, sedimentary and pedogenetic coverings and geobotanical aspects resulting from the various moments of its geological history and which even today is dynamic and intriguing. The soils and sediments of this landscape are varied as their textures (sequences of sandy and clay materials) and mineralogical and chemical compositions, where primary minerals and derivatives of varied degrees of chemical weathering coexist in the same profile, showing moments of contrasting climatic conditions. Even, nowadays it is possible to observe in situ environments with variable dynamics (erosive, sedimentary, pedogenetic, etc.), as well as, several geochemical processes, such as those of oxidation of sandy bars and ravines and also the reductive processes of these ferruginized sands (sometimes, mistakenly confused for lateritic profiles), due to contact with organic acids produced by forest cover and hydromorphic conditions such as they are subjected. Regarding vegetation changes throughout the late Holocene, climate control was observed, but especially edaphic, since this area is seasonally flooded, a fact favored by the clayey nature of the soil surface horizons, the rainfall high rates as a prolonged rainy season (on average 6 months) and extensively flat terrain. Thus, factors such as flood duration and hydromorphism conditions stemming are responsible for controlling the installation of forests and/or savannas that characterize the region. So, the regency of a drier climate with the shortening rainy seasons that causes the water table rise, may represent favorable conditions for the development and advancement of the forest. On the other hand, a wetter climate with longer rainy seasons would cause flooding, covering larger areas and the soils would remain saturated for longer periods, a fact that undermines the advancement of the forest and allows the maintenance or even expansion of savannas, especially those dominated by grasses over the region. However, as already mentioned, the climatic conditions in this region control the expansion of forest formations, but they are not the only protagonists in this process, since the presence of wetland due to low and flat topography, clay soils, soil and sediment saturation is an effective impediment to the forest installation. Another factor responsible for replacing for gallery forest by savanna’s tree, for example, is the channel abandonment, a fact that is currently observed in the region, where it is possible to tread inside these old river beds, many of these places already enriched with species such as Curatella americana and Byrsonima sp among others. The Bananal Island, which is geologically inserted in the context of the Bananal Basin and is bathed by one of the largest hydrographic basins in the Brazilian territory (Araguaia-Tocantins), sets up as an extremely important landscape for understanding the wetlands dynamics and also from the savanna-forest ecotone areas during the Quaternary, since, it fits in both situations. The northern part of the island where this research was developed still needs studies. However, in general, this research has contributed to understand the functional dynamics of this landscape in face of the region climate and environmental changes, as well as to increase the knowledge about the transition landscapes between the Amazon forest and savannas, such as the paleoenvironmental knowledge is still restricted.
Acesso aberto (Open Access)
Dos minerais aos materiais de arquitetura e processos de degradação: edifícios e ornamentos metálicos dos séculos XIX e XX em Belém do Pará
(Universidade Federal do Pará, 2015-06-16) PALÁCIOS, Flávia Olegário; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607
The use of iron in architecture was intensified during the second half of the XVIII century in Europe, and its influence spread over many countries in growth, such as Brazil. Belém (PA) was one of the cites that received the larger amount of building and ornaments imported, especially from England, France, Belgium and Portugal, during the XIX e XX centuries. Currently, Belém holds the largest number of iron architecture heritage remnants in the country. Despite of having great importance in construction techniques, many of these buildings were disassembled and remain on the wait for restoration processes. Also, studies about theses constructions only focus on historical and visual discussion, with no understanding of construction materials, causing empirical restoration processes. The knowledge about these materials is important to the detailed study of historical metal alloys, and different fabrication techniques, as well as weathering action, aiming future restoration processes with scientific bases. The main objective of this research is to understand the historical metals, their diversity in iron architecture and fabrication processes, and also weathering action in iron buildings and ornaments from the XIX and XX centuries in Belém. Thus, the following specific objectives were established: a) physical, chemical and mineralogical characterization of alloys and pathologies; b) identification of different kinds of alloys, in order understand the production types; c) determination of metallurgy evolution imported to the Amazon. The materials chosen for this research came from three different sites, due to their representativeness and diversity of pieces and origin: Mercado de Ferro do Ver-o-Peso building; the former chalet from the State’s Press; and the ornaments from tombs and mausoleums of the Soledade Cemetery. The methods used were Scanning Electron Microscopy (SEM) for physical characterization and punctual chemical analysis; and X-Ray Diffractometry (XRD) for mineralogical analysis. The results were presented in three scientific papers indicating: 1) iron alloys mostly composed by ferrite; 2) textural variations exhibiting four types for the building group: nodular cast iron, gray cast iron type E, wrought iron and gray cast iron type B; 3) three classification of gray cast iron for the ornamental group of diverse origins, among A, B and D; 4) corrosion as main weathering action, and products constituted by goethite and hematite; 4) remnant paint coats, formed by metallic zinc, and its products of alteration represented by zincite and hidrozincite. Through the results of this research it was possible to indicate the evolution of processes in iron architecture production, and enrich this research area with scientific information, as subside for future restorative processes.
Acesso aberto (Open Access)
Efeito do tempo de síntese de zeólita A a partir de caulim amazônico, conformação por extrusão e verificação desta na eficiência de adsorção de NH4 +
(Universidade Federal do Pará, 2015-04-24) SANTOS, Suzianny Cristina Arimatéa; NEVES, Roberto de Freitas; http://lattes.cnpq.br/9559386620588673
Kaolin is widely used in the field of materials (ceramics, pozzolans, fillers and manufacture of paints) as much as the waste and the product received. Currently the most exploited use has been in zeolite synthesis, as it presents the most noble applications. Zeolites are synthesized from silicon and aluminum sources, a fact that justifies the use of kaolin, because it is formed essentially by the clay mineral kaolinite (Al2Si2O5 (OH) 4). In this work we made a kaolin comparison of Grass River region with kaolin mineralogical / chemical and other Amazon kaolin reference to see if you can make it a reference material. The comparison was carried out by size analysis, X-ray diffraction, X-ray fluorescence, scanning electron microscopy, differential thermal analysis and infrared spectroscopy and crystallinity calculations. Moreover, the kaolin of the Rio Capim region was used as a source of silicon and aluminum to obtain the zeolite in order to determine the effect of time on the synthesis. Assays were performed in a time of 30 min, 1 h, 2 h and 24 h applied in these zeolites ammonia adsorption. From the synthesized zeolite was carried out the forming process by extrusion, evaluating various ligands (sodium silicate, bentonite, kaolin and CMC) and firing temperatures (500, 700 and 800 ° C). Later, these were extruded applied also in ammonium adsorption to check its efficiency. It was observed that it is possible to use kaolin Grass River as mineralogical reference material (high degree of structural order) and/or chemical, because it showed performance equal or close to the reference kaolin compared in this work. The zeolite A was synthesized from Amazon kaolin and this presented an excellent silicon and aluminum source. All synthesis times gave zeolite A zeolite in amounts of ~ 600 g. All zeolites showed a high degree of structural view to XRD and SEM. It was also found that synthetic zeolite A in 30 minutes time can be performed without loss in its application, since it presented below only 3% difference in adsorption efficiency compared to 24 h. The shaping by extrusion tests proved promising, 5 out of 10 trials were successful in obtaining granulated with physical strength. However, only the granules containing sodium silicate and CMC as a binder showed a high ammonia adsorption efficiency. With values of ~ 95,5% efficiency in 24 hours of contact.
Acesso aberto (Open Access)
Estudos isotópicos de U-Pb, Lu–Hf e δ18o em zircão: implicações para a petrogênese dos granitos tipo-A paleoproterozóicos da província Carajás – Cráton Amazônico
(Universidade Federal do Pará, 2018-04-05) TEIXEIRA, Mayara Fraeda Barbosa; SANTOS, João Orestes Schneider; http://lattes.cnpq.br/5516771589110657; DALL'AGNOL, Roberto; http://lattes.cnpq.br/2158196443144675
In ca. 1880 Ma an extensive magmatic event generated A-type granites with rapakivi affinity in the Amazonian Craton, especially in the Carajás Province. In this Province these granites are grouped into three main suites according to mineralogy, geochemistry, and state of oxidation of their magmas – Jamon, Velho Guilherme, and Serra dos Carajás – and include also the Gogó da Onça, Seringa, São João, Gradaús, and Rio Branco plutons. The Gogó da Onça Granite (GOG) comprise a stock composed by biotite-amphibole granodiorite, biotiteamphibole monzogranite and amphibole-biotite syenogranite. The GGO crosscut discordantly the Archean country rocks and are not foliated. All Gogó da Onça Granite varieties are metaluminous, ferroan A2-subtype granites with reduced character. The major and trace element behavior suggests that its different facies are related by fractional crystallization. Zircon and titanite U–Pb SHRIMP ages show that the pluton crystallized at ~1880-1870 Ma. This is more akin to the Serra dos Carajás Suite and to the Seringa and São João granites of Carajás and to the Mesoproterozoic Sherman granite of USA and the Paleoproterozoic Suomenniemi Batholith of Finland. New U-Pb SHRIMP data for the Serra dos Carajás, Velho Guilherme and Jamon Suite and for Seringa and São João Granite show that these plutons crystallized between 1880 Ma to 1857 Ma. Some granites of the Velho Guilherme and Jamon suites and of the Seringa Granite presented 1920 to 1900 m. y. old zircon and titanite crystals interpreted here as antecrysts from an earlier pulse of magma that were incorporated in the main later pulse of 1880 Ma. We also obtained ages of 1865 Ma to 1857 Ma in the leucogranite facies of the Redenção and Bannach plutons, which indicate that the leucogranites of these plutons are younger than their ~1880 Ma old granites and were generated by independent magma pulses that are not cogenetic with the less evolved facies of the respective plutons. Besides it, an age of 1732 ± 6 Ma obtained in the leucogranite facies of the Antônio Vicente pluton of the Velho Guilherme Suite that could represent a magmatic event in the Xingu Region not yet reported or, eventually, could correspond to an isolate hydrothermal event that allowed the growth of zircons. This ranites have been also analysed by Lu–Hf and Oxygen isotopes and few granites also by Nd isotopes. Zircons from all the granites have remarkably restricted initial 176Hf/177Hf (0.281156 and 0.281384) and strongly negative εHf(t) values ranging from –9 to -18, and δ18O fairly homogeneous varying from 5.50‰ to 7.00‰. Small differences were observed internally in the plutons or between them. The ƐHf(t) values of the analysed plutons are strongly negative and similar to Nd isotopic data. The Serra dos Carajás Suite has ƐHf(t) values of -14 to -15.5, the Jamon Suite of -9.5 to -15 and values of -12 to -15 for the Velho Guilherme Suite, while São João, Seringa and Gogó da Onça granites have stronger negative values (ƐHf(t)= -12 to -18). Crustal model ages indicate a Paleoarchean source (3.3 Ga to 3.6 Ga) with a minor contribution from Mesoarchean (3.0 Ga to 3.2 Ga) melts for these granites. This model ages are older than the exposed Archean country rocks of the Orosirian granites of the Carajás Province and more investigation is needed to verify the real existence of that older Archean crust. The studied samples have Hf– O isotopic compositions that overlap within error, and evidence of contamination (crustal assimilation or mixing) of a mantle-derived magma cannot be seen. These plutons crystallized from magmas generated by melting of pre-existing igneous rocks with possibly in the Velho Guilherme Suite a minor contribution from a supracrustal (metasedimentary) component. The Nd, Hf, and O isotope compositions of the Paleoproterozoic granites of Carajás Province clearly attest to an igneous ancient crustal source in the origin of their magmas. The differences observed can result for contrasts in the crustal domains of the Carajás Province that were the source of the granites or of local contamination processes.