Programa de Pós-Graduação em Geologia e Geoquímica - PPGG/IG

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2603

O Programa de Pós-Graduação em Geologia e Geoquímica (PPGG) do Instituto de Geociências (IG) da Universidade Federal do Pará (UFPA) surgiu em 1976 como uma necessidade de desmembramento do então já em pleno desenvolvimento Curso de Pós-Graduação em Ciências Geofísicas e Geológicas (CPGG), instalado ainda em 1973 nesta mesma Universidade. Foi o primeiro programa stricto sensu de Pós-Graduação (mestrado e doutorado) em Geociências em toda Amazônia Legal. Ao longo de sua existência, o PPGG tem pautado sua atuação na formação na qualificação de profissionais nos níveis de Mestrado e Doutorado, a base para formação de pesquisadores e profissionais de alto nível. Neste seu curto período de existência promoveu a formação de 499 mestres e 124 doutores, no total de 623 dissertações e teses.

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Acesso aberto (Open Access)
Alteração supergênica das rochas básicas do grupo Grão-Pará: implicações sobre a gênese do depósito de bauxita de N5 - Serra dos Carajás
(Universidade Federal do Pará, 1981-11-19) LEMOS, Vanda Porpino; VILLAS, Raimundo Netuno Nobre; http://lattes.cnpq.br/1406458719432983
The present study deals with the supergene alteration of the basic volcanic rocks of the Grão Pará Group and gathers evidences that support the N5 bauxite deposit (Carajás Sierra) to be an extreme product of this alteration. In the lack of a continuous profile, this hypothesis was tested with a composed profile using the subsurface information available for the contiguous N4 plateau where the whole weathered sequence could be observed. The bauxite-rich and lateritic horizons, only developed in N5, were then assumed to be a part of that sequence and taken as its more superficial levels. The basic volcanic rocks are of precambrian age and were classified as tholeiitic basalts compositionally similar to those of the calc-alkaline suites that occur in modern island ares (TiO2-Zr/P2O5 diagram). The primary mineral assembly is dominantly composed of labradorite and pigeonite-augite and has zircon, ilmenite and opaque minerals as the major accessory phases. Hydrothermal activity caused mineralogical changes in theses rocks producing chlorite, epidote, calcite, sericite, amphibole and quartz. Significant chemical and mineralogical changes were induced by the weathering in these rocks and could be evaluated to depths up to 140 m. The serbidecomposed material showed substantial losses of CaO, Na2O and FeO (this due to partial oxidation to Fe+3) and less important lasses of SiO2, MgO and K2O. In contraposition there was relative enrichment of Fe2O3, Al2O3, TiO2 and P2O5 besides major gains of H2O. This new chemical environment favored the formation of compatible stable phases represented, in order of abundance, by chlorite, smectite-chlorite, opaque minerals and quartz. The totally decomposed basalts revealed an aimost complete loss of alkalls, MgO and CaO, with SiO2 contents dimishing to values of approximately 40% of its initial quantities. This enhanced great relative gains of Fe2O3, Al2O3, TiO2 and P2O5 and H2O with respect to the previous alterations stage. The resulting mineral assembly turned out be dominated by kaolinite, goethite and titanium oxides, and secondarily by gibbsite and quartz. Determinations of Cr, Ni, Co and Zr were done for both the bas.alts and its weathered equivalents. Enrichment factors of the order of 1.5 to 5.0 generally progressive towards the surface indicate the greater or lesser mobility of these elements within the supergene environment. Cr, Ni and Co were retained by coprecitpitation with iron hidroxides while Zr was accounted for by the preservation of zircon as a residual mineral. The N5 bauxite deposit consists of a gibbsite-rich upper layer with an average thickness of 4.7 m and average chemical composition of 3-.13% SiO2, 2.3% TiO2, 47.0% Al2O3, 23.0% Fe2O3 and 24.0% volatiles. Mineralogically it is composed of gibbsite, kaolinite, titanium oxides and iron hidroxides (goethite). The subjacent layers show distinct chemical constitution but the mineral suites differ in the proportions rather than in the kinds of the phases present. Downwards it is observed 1) a lateritic crust as thick as 10 m, 2) a gibbsite-rich clay that do not exceed 35 m in thickness and 3) an argillaceous horizon of indefinite thickness. The lateritic crust has an average chemical composition of 3.6% SiO2, 2.0% TiO2, 28.0% Al2O3, 47.0% Fe2O3 and 19.0% volatiles, and a mineralogy dominated by hematite, kaolinite, iron hidroxides, titanium oxides and subordinate quantities of gibbsite. The gibbsite-rich clay has average proportions of 24.0%, 2.0%, 28.0%, 32.0% and 13.0.% for SiO2, TiO2, Al2O3, Fe2O3 and volatiles respectively while the argillaceous horizon shows average proportions of 47.0%, 1.5%, 20.0%, 22.0% and 7.5% for these same components in that order. The mineral assembly of these two last levels is dominated by kaolinite, gibbsite, titanium oxides and iron hydroxides although hematite appears only in the gibbsite-rich clay while goethite and quartz appear, only ,in, the argillacebus horizon. The identification of heavy minerals in samples of both the decomposed basalt and the bauxite material revealed the same suite consisting of ilmenite, zircon and tourmaline, the latter mineral being found in greater abundances in the bauxite. Boron determinations from samples of the various horizons of both sequentes (N4 and N5) indicated contente that varied from 70 to 100 ppm, justifying /the probable presence of tourmaline even in the rocks from which was not possible to separate heavy minerals. The integration of all these data allowed the interpretation of the N5 bauxite plateau as a residual deposit of the supergene alteration of the volcanic basic rocks of the Grão Pará. Group with basis on 1) the chemical and mineralogical identities between the two sequences, especially the decomposed basalt and the gibbsite-rich clay, 2) the chemical correspondente that suggests the argillaceous horizon to be an intermediate stage of alteration between the semidecomposed and the decomposed basalt, 3) the presence of gibbsite in the decomposed basalt suggesting a stage of evolution which, given enough time and the appropriate conditions, could produce a material progressively rich in alumina and 4) typical trace elements of basic rocks present in relatively high concentrations in the bauxite deposit and, taken the genetic link for granted, showing enrichment or impoverishment factors along a common trend from the unaltered basalt to the bauxite material. Special attention was paid to the lateritic crust that formed underlying the bauxite deposit. It has been interpreted as a result of the relativo mobility of Fe and Pd, under Eh-pH conditions that favored the descending movement of Fe and the fixation of in the upper horizons.
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)
Análise mineralógica por difratometria de raios-X e método de análise de agrupamento (cluster analysis) como critério para individualização de horizontes bauxíticos
(Universidade Federal do Pará, 2017-03-08) OLIVEIRA, Kelly Silva; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607
The formation of wide profile of alteration like as bauxitic deposits on Amazon during Cenozoic period is resultant of intense intemperism caused by seasonal climate, elevated temperature and humidity that are characteristics this region. The bauxitic Province of Paragominas, localized in the east portion the state Pará and west portion of Maranhão, occupies 50,000 km2 approximately forming the largest group of bauxite of Brazil. This work was used X-ray diffractometry, a technique that requires little analysis time, minimum pretreatment steps and small sample amounts, associated with cluster analysis for identify and group samples of same horizon of bauxitic profile of the mine Miltonia 3, Paragominas-PA. The results obtain were correlated with chemical analysis, frequently used for quality control and processing of bauxites. The samples used in this work and your chemical analysis were made available for company Norsk Hydro. The mineralogical types of ore were initially defined through clusters analysis of the XRD patterns of two sections (HIJ-229 e HIJ-231) from polling mesh, with 23 holes each section, and with 375 samples analyzed in all. Based on peak position and intensity of the pattern XRD was possible discern the bauxitics horizons. Due the mineralogic similarity this horizon, the differences found in this group refer principals proportions of minerals constituents: Gibbsite, kaolinite, goethite, hematite, and, more rarely, quartz and anatase. Thought clusters analyses was possible to separate by group a set of similar samples, besides facilitate the analysis of many samples quickly and with efficient results. It was possible yet observe a good correlation of the clusters with the lithotypes identified by the company Norsk Hydro through the results of the chemical analysis. In this way, the analysis of clusters in diffractograms of samples of aluminum ore can be an efficient tool aiding in the protocols of processing of this material.
Acesso aberto (Open Access)
Aproveitamento do rejeito de caulim na produção de alumina para cerâmica e sílica de baixa granulometria
(Universidade Federal do Pará, 2000-11-29) FLORES, Silvia Maria Pereira; NEVES, Roberto de Freitas; http://lattes.cnpq.br/9559386620588673
The Amazon region detains 10% of the world reserves of kaolim. Since the seventy's, two great amazonic beds of kaolim are explored, producing kaolim for paper cover. In the beneficiation process, it's generated an elevated volume of polluted industrial residue which is deposited in extensivas and onerous lagoons of sedimentation. Because of the residue is very voluminous, these lagoons become an environmental problem of great proportions, due the extensivas deforested areas used for their constructions ( Barata, 1998). In this work, are suggested altematives of economic utilization of this residue, which is constituted, mainly, by a suspension of the claymineral kaolinite, for the production of pozolane, aluminium sulphate, the synthesis of the ammonium alum and alumina for ceramics utilization. The methodology constitutes in the drying and the calcination of the residue, followed by the extraction of the AI retained by the acid lixiviation H2SO4 ) followed by the ammonium alum crystallisation, for the reaction with the concentrated NH4OH, by means of pH control, and later calcination at 1200°C, getting a-Al2O3, with no sodium and Iow granulometry. From the aluminas obtained, are made bodies of proof smashed and sintered at 1600°C, to the determination of the ceramics properties, which are compared to one of the commercial alumina. After the acid lixiviation for the AI extraction, results as an insoluble material, an amorphous silica, for which it is suggested, as an additional contribution, an economic application, using it as artificial pozolane in building portland cement, making mechanics tests for the evaluation of its performance. The material that were used and synthesized were characterized throught the use of the X ray diffraction, eletronic scanning microscopy, the infra-red spectroscopy, thermogravimetry, differential thermic analisys, particle size analysis, specific area BET, porosity, chemical analisys throught umid means and throught X ray fluorescence.
Acesso aberto (Open Access)
O arcabouço estrutural da região de Chega-tudo e Cedral, noroeste do Maranhão, com base em sensores geofísicos
(Universidade Federal do Pará, 2002-12-05) RIBEIRO, José Wilson Andrade; ABREU, Francisco de Assis Matos; http://lattes.cnpq.br/9626349043103626; PINHEIRO, Roberto Vizeu Lima; http://lattes.cnpq.br/3251836412904734
The central-northern continental segment of the Brazilian coast, which straddles the boundary between the Pará and Maranhão States, is known in the geological literature as the Gurupi Region. The region is characterized by the presence of two main erosional Precambrian windows which expose small-sized Proterozoic shields in Phanerozoic sedimentary basins. Advances in the understanding of the Precambrian geological history of this area have been limited by the lack and quality of exposures due to the deep weathering profile developed. The use of airborne geophysics proved to be a helpful tool allowing a better definition of some lithological contacts and the shape of major tectonic features. The study area covers part part of the Gurupi Shear Belt, located in one of the Precambrian windows mentioned. This segment of the belt exhibits a variety of sedimentary- and igneous-derived supracrustal rocks in association with plutonic-derived metamorphic rocks. These rocks are structurally organized in three main NW-trending strips which were correlated to the Maracaçumé Complex, Gurupi Group and Tromai Suite. Sheared- and hydrothermally-altered basic and ultrabasic intrusive rocks are often found tectonically interlayered with the Gurupi Group rocks. All the above-mentioned rocks have been metamorphozed under low green-schist to low amphibolite facies conditions and affected by hydrothermal alteration. Diabase dikes crosscut the main Precambrian lithological units along several structural trends. Alluvial deposits along active drainages constitute the youngest lithologic units in the area. The kinematic and geometric analysis of the main tectonic structures observed allows the definition of the area as a shear-belt segment, characterized by steeply-dipping planar structures which are indicative of an oblique left-hand continental collision. The area is also characterized by the presence of a relatively narrow NW-trending highlystrained zone developed along carbonaceous metapelitic lithologic units. This corridor is well defined in the geophysical data and represents an important zone of crustal weakening responsable for most of the deformation partitioning which took place in the area. A secondary NNW-trending shear zone branches off from this main deformation zone and follows the contact of the metapelites with the metavolcaniclastic rocks. The splay caused the detachment of the coarse-grained volcanic rocks from the metapelites. The dominant NW-trending tectonic fabric observed along the exposed rocks of the belt is crosscut by three main sets of fractures well defined by the geophysical surveys, trending N-S, EW and NE-SW. The N-S and E-W fracture sets are associated with drag folds showing sinistral and dextral displacements, respectively. The E-W faults correspond to those previously described by several authors as strike-slip faults. On the scale used, no displacement along the NE-trending fractures could be observed in the geophysical maps, although they control the main river courses in the study area. The NEtrending fractures themselves are not outlined in the magnetic data. In function of this, the available data can not support the idea of some authors who described them as major fault zones related to the the main devolopment of the belt. The N-S fault zones disrupt the NW-trending dominant fabric of the belt exibit left-hand displacements. The N-S, NW-SE and NNW-SSE tectonic fabric present in the region show multiple disruptions, crosscutting one another probably due to several reactivation episodes. The crosscutting relations observed in the geophysical data suggest the N-S fault zones are later in relation to the main NW-trending structures of the belt, although their timings could not be defined with the available data.
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)
Argila de Belterra das coberturas de bauxitas da Amazônia como matéria-prima para a produção de cerâmica vermelha
(Universidade Federal do Pará, 2018-01-10) BARRETO, Igor Alexandre Rocha; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302
The Amazon region holds the largest reserves of bauxite in Brazil, whose deposits are covered by a thick bundle of clay material, known as Belterra Clay (ABT). The wide distribution, superficial occurrence, therefore accessible, and clayey ABT nature have aroused the interest of this work in evaluating its technical viability for the production of red ceramics. For the present study, ABT was selected from the large bauxite deposits of Rondon do Pará, samples of the yellow soils from Mosqueiro, illitic clay and gibbsitic clays and one sample of the clayey siltstone. This clay and other materials used as additives were characterized by X-ray Diffraction (XRD), X-Ray Fluorescence (FRX) (CT), Spectrometric Thermal Analysis (TG), Differential Scanning Calorimete (DSC), Inductively Coupled Plasma Spectrometry (ICP-MS), Coupled Plasma Optical Emission Spectrometry (ICP-OES), Scanning Electron Microscopy (SEM) Laser Particle (APL). To determine the physical and mechanical properties, were produce specimens through different mixtures with the samples of Belterra clay and percentages (20, 30 and 40%) of the yellow soil, clayey siltstone, gibbsitic clays and illitic clay. The specimens were calcined at three different temperature moments (900, 1000 and 1200 ° C). Then, linear retraction, water absorption, apparent porosity, apparent density and bending rupture tension were measured. ABT is essentially kaolinite, having quartz, goethite, anatase and gibbsite as accessory minerals. The pure and simple ABT did not present favorable technological aspects for the production of ceramic products, however the same with addition of the yellow soil and clayey silt from the same region significantly improved the technological characteristics of the ABT.
Acesso aberto (Open Access)
Aspectos neotectônicos e ecologia da paisagem em parte da área dos municípios do NE do estado do Pará (Tucurui, Baião, Breu Branco, Goianésia, Moju e Tailândia)
(Universidade Federal do Pará, 2007-10-30) SOUZA, Francileide de Fátima Rocha; BORGES, Maurício da Silva; http://lattes.cnpq.br/1580207189205228
This work inside investigated the aspects of the landscape and geologic and geomorphological evidences of the neotectonic context in the region that understands the Tucurui Cities until Thailand (Pará). In this region the incidence of neotectonics processes was responsible for the generation of structures, sedimentary sequences, standards of draining net (Basin of the Tocantins River) and relief System. For execution of this study had been used Landsat ETM+ images for the digital processing in platform ENVI 4,0, digital Models of rise supplied by the SRTM/NASA and images of radar SAR analysis of the relief, draining and recognition of the lineaments expressives, analogical bases elaboration of cartographic bases in environment ArcGIS 9.1. The Analysis of the relief, in the investigated area, allowed to identify as genetic groups: ) Group of Degradation - Constituted of System of Mountain ranges (Mountain range of the Trucará) with flattened topos of amplitude varying between 253 and 290 meters, System of Mounts with angular topos up to 180 meters and Colinoso System with 0 amplitude varying it enters m (base level) up to 120 meters, which constitute most of the paisagística expression; b) Group of Agradação - Englobando Aluvial Plain Systems and System of Fluvial Terraces. These systems are shown with geometrias whose joints if give through the installation of discontinuities, characterizing morfoestrutural compartimentação. The integration of the data, deriving of the analysis of the relief, as well as the characterization of the anomalies of draining and the discontinuities, allowed to the recognition of "landorfms" elementary schools tectonics associates the beams of guided lineaments the E-W, NW-SE, NE-SW and N-S. The joint enters beams of neotectonics imperfections gives way to define one extensional romboedro to south of the parallel 3030"S. The romboedral structure is defined by the arrangement between beams of guided discontinuities to NW-SE, with symmetrical trend and apparent transtensive nature and guided beams of discontinuities the E-W, to the center of the area, with probable dominant component "strike-slip". This geometry is cut by to complicate structures guided to NE-SW. Three main beams of guided discontinuities the N-S affect the inquiry area, and represent "landforms" elementary schools tectonics with extensional trend. These structures had been interpreted as decurrent of the reactivation of the Cinturão Araguaia. They are organized in an anti-symmetrical structure with dominant diving for East and in the height of the meridian 49038W they seem to have strong bond with the tracing of the Tocantins River and imposes fort has controlled to the quaternary deposits. The draining net adjusts it to these standards of structural tropia readily, which answer for the presence of anomalous feições as arcs and elbows, and for the installation of standards in treliça, with strong asymmetry, some partially interpreted as treliça of imperfection. Morfogênese of the area in appraise, in that it concerns to its tectônics aspects was admitted as tied to the performance of a binary guided dextral the E-W, fruit of the dynamics established for the current phase of drift of the American South Plate for West.
Acesso aberto (Open Access)
Avaliação ambiental da matéria orgânica degradada nos canais de drenagem da região metropolitana de Belém (PA)
(Universidade Federal do Pará, 1997-01-14) SANTOS, Maria Tereza Primo dos; LIMA, Waterloo Napoleão de; http://lattes.cnpq.br/1229104235556506
Acesso aberto (Open Access)
Avaliação da distribuição das concentrações de mercúrio total em sedimentos, rejeitos, solos e solos com TPA, na bacia do rio Rato-Itaituba/PA
(Universidade Federal do Pará, 1995-08-20) SOUZA, Jorge Raimundo da Trindade; RAMOS, José Francisco da Fonseca; http://lattes.cnpq.br/8189651755374537
The rio Rato located in Itaituba, SW of Pará State, is the principal mercury mining center of the region. The surveied stretch of approximatly 60 km, suffers a great environmental impact, due to gold mining activities. Two field campaigns were conducted and 161 samples were collected for analysis. Total mercury content was determined by cold vapor atomic absorption (CVAS), prior to chemical diggestion with H2SO4, HNO3 and V2O5. The mercury concentration was determined in stream sediments, mining tailings, soils and black earth archeological soils. Organic carbon and loss on ignition (LOI) were also determined to correlate with mercury data. Statistical parameters, such as minimum, maximum, average and standard deviation were used to evaluate the pollution degree of the area and also for comparison with data from other studies. Samples were distributed in seven groups according to field campaign period, type of sample and sample site. For all types of samples, the results obtained from the first field campaign were higher than those from the second campaign, indicating that mining activities are more intense during the dry season. Significant correlation between mercury concentrations and other two variables (organic carbon and LOI) was observed only in a few sample. This observation support the alleatority of the contaminations, and shows that mercury distribution depends on the type of explotation, season, granulometry and sample location. Most samples show mercury concentrations greater than the regional background, which represents a general enviromental contamination.
Acesso aberto (Open Access)
Avaliação das características físicas, químicas e mineralógicas da matéria-prima utilizada na indústria de cerâmica vermelha nos municípios de Macapá e Santana-AP
(Universidade Federal do Pará, 2008-09-30) SOUTO, Flávio Augusto França; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607
The activity ceramic of the State of Amapá still it presents very incipient, not managing to attend the market local. Among the main hindrances diagnosed, we can cite the next: 1) problems in the rental of lain new; 2) ignorance of the physical, chemical and mineralogical characteristics of the raw material (clay); 3) the lack of technical criteria in the raw material extraction. The work goals are: 1) Do the rising, register and to study clays main occurrences geological context for red pottery of the state of Amapá, the which ones are concentrate in the municipal districts surroundings of Macapá and Santana; 2) In occurrences selected, evaluate the chemical and mineralogical characteristics of the raw material, besides the technological-potteries properties, through which wishes the products improvement of red pottery (bricks and tiles). The work was developed in the area that embraces Macapá's Municipal districts and Santana in Amapá, limited by the latitudes (0º0’30”S and 0º3’30”S) and longitudes (51º12’30”W and 51º5’30”W), where are located the biggest numbers of ceramic of the State. The used materials in this work are coming of clays seized by 4 ceramic: Calandrine (CA) and Amapá Telhas (AT)(Macapá); União (U) and Fortaleza (F) (Santana), besides one regarding Corte de Estrada (CE) in Elesbão's District in Santana's Municipal district, representative sample of the Formation Barreiras. In the total were used 12 samples of the 5 cited places, distributed in profiles with average depth of 2,3 m. The methodology constituted in weigh 1 kg of brute sample, drying itself to 50ºC in stove, disintegrating and homogenizer the same. After this initial treatment, separate in four equal parts, it was separating 500 g for file and the remaining for analysis granulometric. Of the fraction clay it accomplished X-ray diffraction analysis (XRD), differential thermal analysis (DTA), thermogravimetric analysis (TGA), espectroscopy in the region of the infrared with transformed of Fourier (spectrums FTIR), chemical analysis (SiO2, Fe2O3, Al2O3, TiO2, CaO, Na2O, K2O, MgO and loss to the fire). For the technological rehearsals they used rules ABNT and were made bodies of proofs of 6x2x0,5cm to determination of the following parameters: color, water absorption (WA) , apparent porosity (AP), linear shrinkage (LS), apparent density (AD), Flexural Strenght (FS), liquidity limit (LL), plasticity limit (PL) and plasticity index (PI). The data obtained through the chemical analysis show great quantity of SiO2, Al2O3 + H2O, associates to the quartz and kaolinite. Values of Fe2O3, TiO2 suggest refractory and changes reduction in the coloration when burnt to 950ºC, besides being linked to the accessory minerals goethite, anatase and hematite. That was observed CaO and MgO are elements that drop for refractory and linked for montmorollonite and muscovite. Already Na2O and K2O, are fundentes important in vitrification process. For X-ray diffraction, thermal analysis and espectroscopy in the region of the infrared revealed the presence of the following minerals: quartz, illite, kaolinite, esmectite (montmorillonite), goethite, anatase. Clays rehearsed characterize for present elevated plasticity with plasticity index (PI) >15% and fraction silte high percentage. The water absorption measures, apparent porosity, lineal retraction and rupture tension to the inflection after burning in oven in the temperatures of 950ºC and 1050ºC, they presented values adequate for clays use in industry of red pottery. According to the measures obtained in the technological-ceramic rehearsals for the bodies of proofs burnt in the temperatures of 950ºC and 1050ºC, they contacted the next applications in clays studied: 1) Burning temperature to 950ºC - For masonry bricks 10 samples served (U-01, U-02, U-03, F-01, F-02, AT-01, AT-02, CA-01, CA-02, CA-03); for structural bricks 8 samples served (U-01, U-02, U-03, F-01, F-02, AT-02, CA-01, CA-03); and for tiles just 5 samples they presented inside the standards (U-01, U-03, F-02, F-01, AT-02). 2) Burning temperature to 1050ºC - 10 samples they presented inside the standards demanded for tiles production, masonry bricks and structural (U-01, U-02, U-03, F-01, F-02, AT-01, AT-02, CA-01, CA-02, CA-03).
Acesso aberto (Open Access)
Biogeoquímica comparativa de ecossistemas de floresta sucessional e Virola surinamensis na região dos tabuleiros costeiros do estuário guajarino, Amazônia oriental, Brasil
(Universidade Federal do Pará, 2005-04-14) OLIVEIRA, Francisco de Assis; RAMOS, José Francisco da Fonseca; http://lattes.cnpq.br/8189651755374537
Studies of comparative biogeochemistry of Virola surinamensis (VSU) and successional forest ecosystems (FSU) in the coastal tableland region of eastern Amazonia were carried out to studies on i) factors that cause differences in fluxes and stocks of organic matter and chemical elements, such as potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), copper (Cu) and zinc (Zn) within the biogeochemical matrix of litterfall, the forest floor and pedochemical matrix stocks, and ii) factors that control the variation in soil carbon dioxide (CO2) flux within the VSU and FSU ecosystems. The major flux of the biogeochemical matrix (organic matter) from the trees to the forest floor was higher (p < 0,001) in the successional forest ecosystem (FSU) than in the Virola surinamensis ecosystem (VSU). This was due to higher floristic diversity in the FSU, as well as the elevatedlevel of ecosystem manipulation in the VSU, where the burning of phytomass released K, Ca, Mg, Mn, Fe, Cu and Zn oxides, causing in situ enrichment of the soil bases. The K, Mn and Zn fluxes were significantly higher (p < 0,001) in the FSU, although Fe flux was higher (p < 0,001) in the VSU. These results show the effect of high floristic diversity of the biogeochemical matrix in the successional ecosystem, while in the Virola surinamensis ecosystem, results indicate the possibility of biogenic Fe accumulation as a genotypic character of Virola tree species. The Mg, Ca and Cu fluxes were similar (p <.0,05) between ecosystems, as demonstrated by the semivariogram nugget effect. This indicated the absence of spatial influence on the processes controlled by the biogeochemical matrix flux. The geochemical matrix flux occurred with similar patterns at the mesoscale level, or across the biogeochemical provinces. The element use efficiency (EUE) for Ca, Mg, Mn, Fe, Cu and Zn was greater (p < 0,001) in the FSU than in the VSU. This indicates a significant biogeochemical matrix flux effect in the successional forest ecosystem, contrary to the Virola surinamensis ecosystem with relatively low floristic diversity. Potassium (K) occurred with similar EUE values (p > 0,05) in both biological systems suggesting that the VSU ecosystem was an efficient K cycler. The forest floor stocks of K, Ca, Mg, Mn, Fe, Cu and Zn were higher (p < 0,001) in the FSU than in the VSU. This may be explained by the more diversified biogeochemical matrix control in the forest successional ecosystem. The overall water holding capacity was similar (p > 0,05) between ecosystems, although forest floor storage was higher (p < 0,001) in the FSU, indicating that the VSU ecosystem has recovered its structure and function over time. The biogeochemical matrix mean residence times for forest floor organic matter and K, Ca, Mg, Mn, Fe, Cu and Zn were higher (p < 0,001) in the successional ecosystem (FSU) than in the Virola surinamensis ecosystem (VSU). This suggests that in FSU the influence of forest floor stocks worked as a proximal factor, associated with the more distal factor of higher floristic diversity, which likely introduced recalcitrant substances into the system to minimize the decomposition process. The dispersion models illustrated in semivariograms for Al, Na, Fe and Cu in the Yellow Latosol dystrophic (LAd), and Ca in the Yellow Latosol dystrophic endocrecionary (LAdc) showed a nugget effect. In the LAd soil pedochemical system, the semivariograms models demonstrated spatial dependence, including H+ (spherical, r2 =0.92); Na (gaussian, r2 =0.49); K (gaussian r2=0.98); Ca (exponential, r2= 0.82); Mg (gaussian, r2 = 0.87); Mn (exponential, r2 = 0.86), Zn (gaussian, r2 =0.79). In the LAdc soil, cations that showed spatial dependence were Al (gaussian, r2 = 082); H+ (gaussian, r2 = 092); Na (gaussian, r2 = 0.87); K (gaussian, r2 = 0.86), Mn (gaussian, r2 0.96) and Fe (gaussian, r2 = 0.87); Cu (gaussian, r2 = 0.80) and Zn (gaussian, r2 = 0.79). Carbon dioxide (CO2) flux from soils in the were similar (p > 0,05) with values of 4,03 μmol C m-2 s-1 and 4,37 μmol C m-2 s-1 in the VSU and FSU, respectively. Based on the CO2 soil efflux, I conclude that the Virola surinamensis ecosystem attained similar metabolic processes in relation to the successional forest ecosystem over time.
Acesso aberto (Open Access)
O Cambriano no Sudeste do Cráton Amazônico: paleoambiente, proveniência e implicações evolutivas para o Gondwana Oeste
(Universidade Federal do Pará, 2018-06-15) SANTOS, Hudson Pereira; NOGUEIRA, Afonso César Rodrigues; http://lattes.cnpq.br/8867836268820998
Transgressive events recorded in many cratonic regions marked the Cambrian period, hypothetically related to the glacioeustasy and/or the progressive opening of the Iapetus ocean (~600 Ma). Such events influenced the paleoceanography of this period, including the progressive biota evolution – the ‘Cambrian Revolution’. Although the Gondwana Supercontinent margins, entirely amalgamated in the Lower Cambrian (540 Ma), were flooded, the inner part of this supercontinent was emergent, probably triggered by postcollisional epirogenic uplifts. Epeiric seas covered subsiding areas with projections towards the interior of the Western Gondwana, developing shallow platforms that covered ancient colisional suture zones. In the southeastern Amazon Craton, the recurrence of platform environments dates from Upper Cryogenian (~635 Ma) until the Cambrian with the installation of glacial deposits, overlaid by carbonatic and siliciclastic successions. Despite the previous insertion in the context of a foreland type basin related to the evolution of North Paraguai Belt (650-640 Ma), these deposits have been included in an inverted intracratonic basin in the Ordovician. The bottommost deposits of the Cambrian sequences, here presented, are comprised dominantly by siliciclastic rocks. These consist in the Upper and Lower members of the Raizama Formation and the base of Lower Member of the Sepotuba Formation, Alto Paraguai Group, exposed in the central and northeast portions of the inverted intracratonic basin, Mato Grosso state. Two depositional sequences (DS1 and DS2) characterize the Cambrian successions of the base of Alto Paraguai Group. The DS1 presents as a sequence boundary (SB1) an erosional hiatus previously interpreted in the southwestern basin. This stratigraphic surface becomes a correlative conformity towards the central and northern portions, where this covers the Araras carbonates and Cryogenian glacial deposits from Puga diamictites. The SB1 represents an erosional or non-depositional period of approximately 80 Ma developed over the carbonates of the Lower Ediacaran Araras Group, related to the epeirogenic uplifts of the basin. A second thermal subsidence phase would have led to the installation of a siliciclastic platform during the Cambrian, characterized by DS1 composed by two facies associations denominated FA1 and FA2. FA1 consists of subarkoses, quartz-wackes and pelites dominated by wave and storm processes, inserted in the offshoretransition, lower-middle shoreface and upper shoreface zones. The presence of infaunal vertical trace fossils belonging to the Skolithos Ichnofacies (Skolithos linearis; Diplocraterion parallelum; and Arenicolites isp.) at the base of the lower-middle shoreface deposits indicated a Lower Cambrian age, or younger, to the Raizama Formation, previously considered as Ediacaran. The FA2 comprehends subarkoses, quartzarenites, sublitarenites, quartz-wackes and sandstone/pelite rhythmites interpreted as complex tidal plain deposits, unconformably overlaid (SB2) by braided fluvial channel deposits of (FA3), which belong to the DS2. The DS1 would have been deposited during lowstand to transgressive system tract, organized in progradational parasequences. This stacking pattern is not compatible with the traditional stratigraphy sequence for TST, which is attributed to a slow subsidence rate concomitantly to a high sediment supply indicated by the Skolithos Ichnofacies. Subsequently, a less expressive drop in the sea level promoted a progradation of distal braided deposits (FA3) over the DS1, related to the lowstand system tract (LST) characterized by an abrupt change of the tidal heterolitic deposits to medium and coarse-grained quartzarenites from fluvial deposits. Paleoflow data oriented preferentially to NE and SE obtained in coastal beds from FA2 and FA3 allied to the Paleo- to Mesoproterozoic U-Pb detrital zircon ages have indicated provenance exclusively from SW and NW sources from Amazon Craton. Besides that, the detrital quartz grains analysis of sandstones of the bottommost Cambrian deposits indicate mainly igneous and metamorphic sources. Previous works indicated that the fluvial deposits of DS2 were succeeded by a transgressive system tract, marking this as the last transgressive event that influenced the Cambrian deposits of the intracratonic basin. Slowly, the ocean connection was interrupted as a consequence of the closing of Iapetus Ocean (~500 Ma) as a result of basin uplift. In this way, Cambrian epeiric seas were confined and consequently started the lacustrine phase of the basin in the Ordoviacian, represented by the Diamatino Formation deposits. Posteriorly, the intracratonic basin of the southeast Amazon Craton would have been inverted by the transtensional tectonics which propitiated the implantation of post-Cambrian intracontinental basins of the Western Gondwana.
Acesso aberto (Open Access)
Caracterização biogeoquímica de ecossistemas amazônicos: rios e lagos selecionados das microrregiões Bragantina, do Salgado e Guajarina - PA
(Universidade Federal do Pará, 1999) MENEZES, Lúcia Beckmann de Castro; LIMA, Waterloo Napoleão de; http://lattes.cnpq.br/1229104235556506
It was compared physical, chemical, physical-chemical and hydrobiological environmental parameters of waters and of aquatic humic material, in three kind of places seemingly identified, because these parameters are excellent indicators of biogeochemical and ecophysiological characteristics of aquatic ecosystems, in the attempt of characterizing the influence of the biogeochemical factors of pollution, the anthropogenic influence and the studied ecosystems productivity. It was collected samples in the course of the Guama river, in Ourem – Bragantina zone (high course), in Bujaru (medium course) and in Belem - Guajarina zone (close to estuary), as well as in two lakes of coastal plain located in the island of Atalaia (Salinopolis), and still in the Arapepo river (municipal district of Salinopolis – Salgado zone), this one under strong influence of the waters of the Atlantic ocean, in the months of December of 1996 (drought period), May of 1997 (rainy period) and October of 1997 (drought period). The methods used in the characterization involved physical-chemical analysis and chemical analysis for the determination of the chemical composition in relation to the dominant ions and the indicators of the presence and of the decomposition of the organic matter (humic material) and hydrobiological analysis, for chlorophyll evaluation, in natural waters, submitted or not to an anthropic action. It was utilized the ultraviolet and visible spectrophotometry and in the infra-red spectroscopy to the characterization of the natural organic matter, where the humic acid and fulvic acid prevail. The spectra in the ultraviolet-visible were also used for the identification of the chlorophyll. The analytic results have showed a clear difference among the studied ecosystems, suggesting an influence of an anthropic action in the Guama river, which characterizes the lakes in Salinopolis as an ambient with high amount of organic matter (humic substances) and the Arapepo river presenting results very differents due to the oceanic influence and to the occurrence of mangroves in its margins, being the only ecosystem where the occurrence of photosynthetics pigments were perceived (chlorophyll). The calculation of the ionic relation indicated the presence of marine intrusion in the environments of the lakes I and II, Arapepo river and Guama river (Belem). The seasonal was reflected intensively in the three studied ambients, through parameters as color, turbidity, specific conductivity, chloride, sulfate, organic matter (consumed oxygen), iron and the larger cations (calcium, magnesium, sodium and potassium), notedly in the physiografic area of the Salgado zone. The relation carbon/nitrogen observed for the humic substances suggests that the humic material of the lakes has an older formation than the rivers. The rate E4/E6 obtained through the spectra in the ultraviolet-visible indicates that the humic and fulvic acids present in the samples have a high aromaticity. The interpretation of the spectra of absorption in the area of the infra-red, has permitted to verify that there are present the most characteristic bands, indicating the presence of groups C-H, C=O and COOH and also of aromatic skeleton and suggesting the formation of humic substances - metal complex, what is in conformity with the analytic results obtained for metals in the humic material. The amount of metals (iron, manganese, copper, chromium and zinc) presents in the humic material were always larger in the samples of the Guama river (Belem), what suggests enrichment due to anthropogenic influence.
Acesso aberto (Open Access)
Caracterização geoquímica das drenagens afetadas pelo beneficiamento de ouro no distrito aurífero de Ginebra, departamento del Valle Del Cueda, Colômbia
(Universidade Federal do Pará, 1995-10-30) RAMOS, Jader Muños; RAMOS, José Francisco da Fonseca; http://lattes.cnpq.br/8189651755374537
The gold-bearing district of Ginebra shows regionally three well defined geological units: the Amaime formation (tectonized pillow-laves), the ophiolitic massif of Ginebra (sequency of peridotites, gabros, metabasalts, plagio-granites and micro-breccias) and the Buga”s batolith (quartz diorite varying to tonalite). The Buga”s batolith intrusion in the ofiolitic massif of Ginebra produced a hydrotermal alteration and a gold bearing sulfide mineralization in the contact zone, resulting a stockwork-like gold-bearing deposit surrounded by gold-bearing veins. The local miners have explored and exploted the district for almost a century, using rudimentar tecniques. A part of the ore and the tails are dispersed by gorges flowing into the Guabas river, from where the water for the municipal aqueducts of Ginebra e Guacarí is taken. This 1s the importance of this study. To obtain the geochemical evaluation of the heavy metal levels in the drainages of the zone, 27 water samples were collected in the district and analysed for As, Au, Co, Cr, Cu, Fe, Mn, Ni and Pb. Aditionally, 28 sediment samples (27 of stream sediments and 1 of suspension sediment) from the same zone were analysed for Ag, As, Au, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn. The statistical treatment applied to the results showed local anomalies related to the dispersion of mining tails. 4 Anomalous concentrations for As, Au, Co, Cr, Cu, Fe, Mn, Ni and Pb, as metals in solution in the waters, were detected near to the input of the effluents of mine to the gorges, due to a decay of the pH by oxidation of the sulfides within it. The pH background, varying from slightly basic to basic, is a geochemical barrier that decreases the anomalous concentrations of metals to normal levels in the waters, increasing their concentrations in the sediments. The stream sediments showed local anomalies for As, Au, Co, Cu, Hg, Mn, Ni, Pb and Zn. The mercury detected in the district has an antropogenic source. This metal is used for gold amalgamation. Dangerous emissions of mercury to the stream sediments and the air are released by losses of amalgama”s recoverying and amalgama”s burning (to recover the gold). The airbomne transport of mercury was deduced by the observation of a vertical variation of the Hg concentrations in the soils. The possibility of higher antropogenic changes on the pH and Eh conditions in the waters of the district gorges, the mechanical remobilization of the sediments with high heavy metal concentrations and the airborne transport of mercury justify a continuous monitoring of the concentrations of heavy metals in solution in the waters for domestic use at the municipalities of Ginebra and Guacarí and the suspension sediments within it. These analysis must be accompanied by technical directions for the use of mercury and recovering of gold, for the miners of the district, minimizing the environmental agressions.
Acesso aberto (Open Access)
Comportamento de metais pesados e nutrientes nos sedimentos de fundo da Baía do Guajará e Baía do Marajó
(Universidade Federal do Pará, 2010-01-28) HOLANDA, Nielton de Souza; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607
Human activities influence the physical and chemical characteristics of water, sediments and organisms in aquatic environments located in industrialized areas and high population density. With the increasing use of estuaries as a reservoir for a large amount of waste, coastal and estuarine ecosystems are gradually being subject to significant impacts. The bottom sediments play an important role in the investigation of these impacts since it has the ability to retain chemical species and inorganic. The objective of this research is to study the geochemical behavior of metals in the bottom sediment of the Bay of Guajará, Guama River and the Bay of Marajo. The two regions were chosen for their opposite characteristics: a Guajará Bay Area (1) under strong anthropogenic influence and Marajó Bay Area (2) considered the reference. We collected 83 points in Area 1 and 60 points in Area 2. Determined chemical concentrations of the following metals: Ba, Cr, Cu, Fe, Pb, Ni, V and Zn, and also the levels of nitrogen, carbon, organic matter, total phosphorus and phosphorus bound to organic compounds. Area 1 shows the average content of nitrogen of 0,08 %, mean levels of carbon and organic matter from 1,51 % and 2,60 %, respectively. The concentration of phosphorus and phosphorus bound to organic compounds 307 mg / kg and 126 mg / kg, respectively. The concentration of metals showed the following values: Ba (529 mg / kg), Cr (91 mg / kg), Cu (17 mg / kg) , Fe (6,82 %), Ni (32 mg / kg), Pb (27mg / kg), V (120 mg / kg) and Zn (69 mg / kg). Area 2 shows the average content of organic matter 1.70 % of carbon and nitrogen 0,98 % and 0,08 % respectively. The concentration of phosphorus and phosphorus bound to organic compounds 193 mg / kg and 7 mg / kg, respectively. The concentration of metals showed the following values: Ba (596 mg / kg), Cr (102 mg / kg), Cu (21 mg / kg) , Fe (8,31 %), Ni (40 mg / kg), Pb (28 mg / kg), V (141 mg / kg) and Zn (85 mg / kg). The carbon and phosphorus (0,98 %, 193 mg / kg), respectively found in area 2 were lower than those found in area 1 (0,51 %, 307 mg / kg) and demonstrate the influence of effluents that are released in the estuary Guajarino. In both areas there is the same downward trend in levels: Fe2O3> Ba> V> Cr> Zn> Ni> Pb> Cu. In area 1 were found higher metal alone while in area 2, with the major averages, the distribution is homogeneous, two areas in the metals has a slight tendency to concentrate where there is a higher content of organic matter.
Acesso aberto (Open Access)
Dispersão geoquímica dos elementos Si, Al, Fe, Mn, Na, K, Cu e Zn nos solos e sua aplicação na caracterização de áreas geoquimicamente homogêneas
(Universidade Federal do Pará, 1980-05-13) SILVA, Waldise Rossycléa Lima da; RONCAL, Juan Rolando Zuleta
Variations in the chemical composition of soils are used to characterize sub-areas geochemitally homogenous. The aplication of this methodology in a tropical humid region of accentuated topography constitute the principal objective of the present research. Samples of red latosols (Horizon B) developed over gravite, sandstone and basalt occurring in the Central Granite Region of the Serra dos Carajás, Pará State, Brasil were analized for the elements Si, AL., Fe, 40Mn, Na, K, Cu e Zn, by atomic absorption spectrophotometry. Based on the criterion of similarity in the chemical composition (Cluster Analysis, Factor Analysis) the soils were separeted in to different groups. The geographical distribution of the different groups permit the establishment of a Glose relationship between the different parent lithologies and their corresponding soils.
Acesso aberto (Open Access)
A Distribuição dos elementos Cu, Au, Co, Zn, Ni, Mn, e Fe em solos sobre o depósito de Cobre de Salobo -3A, Serra dos Carajás
(Universidade Federal do Pará, 1985-10-04) HERRERA, Marco Túlio Guillen; RAMOS, José Francisco da Fonseca; http://lattes.cnpq.br/8189651755374537
Acesso aberto (Open Access)
Distribuição dos elementos Si, Al, Fe, Ca, Mg, Mn, Ti, Cu, K e Na em solos desenvolvidos na região do granito central da Serra dos Carajás - sul do estado do Pará
(Universidade Federal do Pará, 1981-03-13) DAMOUS, Nina Rosa Leal; RONCAL, Juan Rolando Zuleta
The distribution of elements in the weathered pro rocks is effected mainly by climate, geomorphology and parent material. The present study deals with the distribution of Si, Al., Fe, Ca, Mg, Mn, Ti, Cu, K and Na in the weathered products of the Central Gravite at Serra dos Carajas - Para, Brazil, which occurs in an area which is characterized by ondulated relief and humid tropical climate. Samples representing two selected weathering profiles were collected to depths that did not exceed 6 m. The analytical treatment consisted of poten/biometric determinations of pH values, the determination of the chemical and mineralogical compositions of the sand, silt and clay fractions, and the determination of the chemical composition of the oxide fraction. The two profiles reveal an intensa process of feldspar removal from the parent granite and the formation of a sand-clayey lato-soil. In this process quartz has been preserved and clay minerals and aluminium and iron hidroxides have been formed constituting the dominant assemblage of the soil. Ca, Mg, Mn, Na and K from the parental rock were nearly completely leached away to the extent that these elements are only found in small amounts in the remaining feldspars or adsorbed on clay minerals. On the other hand, Ti present principally in resistant minerals, practically maintains its' original concentration. Cu is sligthly enriched in the profiles due to adsorption in the clay minerals. The presence of only very small amounts of feldspar along the profiles shows the great intensity of the weathering process acti.ng on the granitic rocks. The direct transformation of feldspar to clay minerals or aluminium oxides is related to the climatic conditions frainy and dry seasons) prevalent in the area.
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.

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