Navegando por Assunto "Rio Capim - PA"

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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)
Caracterização geológica, mineralógica, química e física do caulim da Mina da RCC-Rio Capim Caulim (PA)
(Universidade Federal do Pará, 2000-07-24) SOUSA, Daniel José Lima de; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607
Acesso aberto (Open Access)
Caracterização mineralógica e geoquímica e estudo das transformações de fase do caulim duro da região do Rio Capim, Pará
(2003-12) CARNEIRO, Bruno Santana; ANGÉLICA, Rômulo Simões; SCHELLER, Thomas; CASTRO, Elton Anderson Santos de; NEVES, Roberto de Freitas
The Capim region (Pará State, northern Brazil) is the most important kaolin district in the Amazon region, with the largest Brazilian reserves of high whiteness kaolin for the paper coating industry. The main ore (soft kaolin horizon) is located at a depth of about 20 m, being covered by a hard, iron-rich kaolin level, also called flint or semi-flint kaolin, besides a sandy-clay overburden. The beneficiation of this kaolin produces large volumes of wastes, composed mainly of coarse-grained kaolinite, deposited in basins that occupy extensive areas. The main objective of this work is to carry out mineralogical and geochemical studies of the hard kaolin, and to evaluate its thermal transformations through calcination up to 1500 oC. The results show a mineralogical composition dominated kaolinite. The evaluated thermal transformations allows us to describe a series of chemical reactions from kaolinite to metakaolinite and further development of spinel, cristobalite and mullite. For the two analyzed samples, such transformations can start at different temperatures as a result of the different chemical compositions, mainly the iron contents.
Acesso aberto (Open Access)
Do tempo dos pretos d’antes aos povos do Aproaga: patrimônio arqueológico e territorialidade quilombola no vale do rio Capim (PA)
(Universidade Federal do Pará, 2012-10-01) MORAES, Irislane Pereira de; MARQUES, Fernando Luiz Tavares; ALMEIDA, Marcia Bezerra de; http://lattes.cnpq.br/1085631337892211; http://lattes.cnpq.br/0365104813041022
This master's dissertation were built from the dialogue between anthropology and archeology, seeking to understand the uses and meanings that archaeological heritage plays in the field of contemporary social relations, specifically, those built according to the logic of traditional peoples and communities. Understood as an ethnographic category, heritage allows a glimpse on the meanings of quilombolas communities from Taperinha, Nova Ipixuna, Sauá-Mirim, Benevides and Alegre Vamos, in São Domingos do Capim (State of Pará), draw around the archaeological site Aproaga. In the struggle for definitive titration of its territory the quilombolas define themselves as Peoples of Aproaga, in this context, cultural awareness enables the construction of collective identity. Around the historic ruins of the Greathouse of Sugar Plantation from the colonial age, the social memory about the time when the Blacks were slaves restores and strengthens the present cultural references and ethnic boundaries in consonance to the feeling of belonging to Aproaga. Thus, public archeology and ethnography allows us to understand the dynamics and social relations of the present and its fruitions with the past, the meanings of material culture as well, the ethnic dimensions which heritage might take in the context of territorial rights of communities descendants and / or origin. Whereas, the territoriality quilombola built by the People of Aproaga imply a critical way of thinking about heritage policies in Amazon, and more broadly the reflexivity of the research towards a decolonial science praxis.
Acesso aberto (Open Access)
Elementos traços no caulim do Rio Capim, estado do Pará
(Universidade Federal do Pará, 1977-10) MONTEIRO, Reginaldo Wanghon; SCHWAB, Roland Gottlieb
The parent rock material controls the trace element content of a kaolin. The trace element association of Rio Capim kaolin is examined and utilized to verify the provenance of the deposit. The method of emission spectrographye is used for the analysis and is described in its essential parte, in particular the construction of the work curve and the detection limite of the elements The trace element association of the deposit is compared with the trace element association of other kaolin deposits of known provenance. On the basis of this comparison, it is concluded that the deposit was formed by weatering of a granitic parent rock. These conclusions confirm geologic observations about the deposit and the assemblage of heavy minerals, indicating a paraautochtonic origin.
Acesso aberto (Open Access)
Investigação da reatividade e da cinética de dissolução do metacaulim em ácido sulfúrico
(2013-06) LIMA, Paula Elissa Antonio de; ANGÉLICA, Rômulo Simões; SCHELLER, Thomas; NEVES, Roberto de Freitas
A study about reactivity and dissolution kinetics of metakaolin was carried out using kaolin for paper coating derived from the Rio Capim region, Pará state, northern Brazil. The kaolin was burned at 600, 700, 800, 900 and 1000 ºC during 2 h in order to obtain metakaolin, followed by leaching with sulfuric acid at constant temperatures within the 50-95 ºC ± 3 ºC range. In the leachings, amounts of sulfuric acid corresponding to 10% above the stoichiometric values were used with respect to aluminum present in the material. Samples were collected in predetermined intervals every 15 min until a total time of 3 h, which were subjected to aluminum analysis by the EDTA titrimetric method. The results showed that the reactivity of burned kaolin decreased with the increase of burning temperature and that the dissolution kinetics of aluminum from metakaolin obtained by burning at 700 ºC followed the methods of homogeneous reaction used: integral method, method of half-lives and method of initial rates. 96.25 kJ/mol of activation energy was found as well as leaching reaction of the first order with respect to aluminum from metakaolin and the first order with respect to acid concentration. Researches carried out previously, using one of the reagents with excess above 90% and models of heterogeneous reaction, are consistent with the data found in this paper developed with only 10% excess.
Acesso aberto (Open Access)
As mudanças no uso e cobertura da terra e o comportamento hidrológico da bacia do rio Capim
(Universidade Federal do Pará, 2018-04-09) DIAS, Gustavo Francesco de Morais; LIMA, Aline Maria Meiguins de; http://lattes.cnpq.br/6572852379381594
The implications of changes in land use and land cover affect the hydrological behavior of river basins; In this context, the catchment area of the Capim River located in the northeast of the State of Pará is inserted. The objective of this study was to relate the flow behavior with changes in land use and land cover for the years 2004, 2008, 2010 and 2014. For this, land use and land cover data from the TerraClass project was used to identify the proportion of the classes in the basin and in the APPs; for the evaluation of the hydrological behavior the average monthly flow and the quarters of higher and lower flow were analyzed, besides the spatialization and the behavior of the precipitation in the period from 1983 to 2014. The results indicate a reduction in the forest class for the Capim river basin , and an increase in the pasture and agriculture classes, but in the APPs an increase of the forest class was identified in the period from 2004 to 2014. There was a high correlation, both for the uses and coverages of the whole basin and for only the APPs of the resources between the forest and pasture classes with the flows of the Capim river. The analysis of the basin landscape showed an increase in forest fragmentation, and the metrics with the highest correlation with the flow behavior were total forest edge (TE) metrics, pasture aggregation index (AI) and intercalation index, and juxtaposition (IJI) and AI of agriculture; indicating that the fragmentation of the forest cover of the basin and expansion of the areas destined to pasture has been reflected in the behavior of the flow.
Acesso aberto (Open Access)
Uso da capoeira na extração de lenha: em três comunidades locais no pólo Rio Capim do PROAMBIENTE-PA
(Universidade Federal do Pará, 2006-09-14) LOPES, Barto Monteiro; MENEZES, Maria de Nazaré Angelo; http://lattes.cnpq.br/2943083062747137; KATO, Osvaldo Ryohei; http://lattes.cnpq.br/4241891652832872
The firewood is one of essential products for the small husbandman, for being the main source heater energy, used on its daily activities. This energy is gotten from the cleared land and secondary vegetation, and are used from husbandman. The objectivities here, is to identify which the most important forest species used by producers to obtain firewood from the husbandman practices on; estimating the consumption of firewood per people; analyzing the chemical, physical and energy characteristics of firewood; and inquiring their potentialities to produce coal and condensable gases. The research was achieved in three local communities: São José do Itabocal and Fé em Deus, both are located at São Domingos do Capim and, Santa Rita community, at Mãe do Rio, all of them belong to Polo Rio Capim of PROAMBIENTE program, in the northeast of Pará. The method used was the study of multiple cases, using for that, many kind of devices, as field research: interviews, questionnaires, direct comment, field notebook, further on laboratory analysis of the physical, chemical and energy characteristics of the firewood. About the results, we can emphasize that 61,3% of husbandman, need firewood to use in the cassava flour house, where is the principal fuel used for preparing the cassava flour. Moreover, its as bigger use is in the food firing, being Itabocal the community more dependent of this heater source. Seventeen species of tree were found, that are used as fuel, emphasizing the lacre, mitaceira and ingá. The firewood consumption was gotten per people, on the order of 3,80, 3,68 and 2,51 kg/ people /day for the communities of Fé em Deus, Itabocal and Santa Rita, respectively. For the production of firewood and vegetal coal, they stood out the mitaceira and ingá based, mostly, in the apparent specific masses of the analyzed material of the related species (0,52 g/cm3 and 0,53 g/cm3, respectively) for the choice as firewood; and in the incoming in fixed carbon; for the choice of use as coal, statistics superior to the one of the third analyzed forest species (lacre), 24,15% and 23,70%, respectively. For the production of condensable gases, emphasizing the lacre (with Incoming in Condensable Gases = 44,93%), with a great potential of the use of relatives husbandman part.