Navegando por Autor "QUEIROZ, Maria Mireide Andrade"

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Geoquímica das águas do médio e baixo rio Madeira e seus principais tributários - Amazonas - Brasil
(Instituto Nacional de Pesquisas da Amazônia, 2013-12) HORBE, Adriana Maria Coimbra; QUEIROZ, Maria Mireide Andrade; MOURA, Candido Augusto Veloso; GALARZA TORO, Marco Antônio
The aim of this paper was study the water of the Madeira River and its tributaries, between the city of Humaitá and its confluence in the Amazon River. There were analyzed: pH, conductivity, turbidity, major ions, trace elements and strontium isotopes during the dry and wet seasons and also, in the transition from the wet to the dry season, throughout 2009 and 2010. The white waters from the Madeira River are bicarbonated, calcic, with pH between 5 and 6 and the ions concentrations are higher than those of the tributaries. The waters of the tributaries are black, are more acidic and are chemically heterogeneous; those from the left margin are chemically similar to the waters of Madeira River, while those from the right margin are enriched in dissolved SiO2. The concentrations of cations, Cl- and NO3- are higher during the wet season due to the contribution of soils, vegetation and the rainwater composition (Cl-), while HCO3-, SO42-, Al, Br e P are concentrated in the dry season, and their higher contents may be related to the bedrock. The higher concentrations of SiO2 and rare earth elements in both dry and wet season are related to vegetation, soil and rocks. The interaction of these factors causes the chemical heterogeneity of the water. However, the chemical similarities between the water tributaries of the left margin and the water of the Madeira River, are probably, consequence of the Andean rocks be the sources of the Cenozoic sedimentary rocks percolated by these tributaries while the chemistry water of the tributaries of the right margin are in accordance with the tectonic stability, the intense weathering and the low erosion rate of the Amazon craton.
Acesso aberto (Open Access)
Hidrogeoquímica do baixo e médio rio Madeira e de seus principais tributários, Amazonas – Brasil
(Universidade Federal do Pará, 2011-08-30) QUEIROZ, Maria Mireide Andrade; MOURA, Candido Augusto Veloso; http://lattes.cnpq.br/1035254156384979; HORBE, Adriana Maria Coimbra; http://lattes.cnpq.br/9250333089025975
The present work addresses the Madeira River along with its effluents’ waters and sediments, from the city of Porto Velho right down its mouth into the Amazonas river, aiming to determine the compositional and mineralogical influence brought about by sediments carried by the large Amazonian rivers with headwaters, in the Andes, originating from cratonic rocks. Major ions, trace elements, including REEs, and Sr isotops were analyzed in the waters during three hidrological periods, low water, high water and transition, between 2009 and 2010. On sediments we carried out a study based on granulometric, mineralogical, chemical, including Pb isotop, analyses. There is an apparent hidrological cycle control on the chemistry of the waters, yet it acts in a differentiated mode according to the dissolved element order of greatness, since in both the Madeira river and its tributaries water, most trace elements present greater dilution in high water, whereas for REEs, this occurs in low water, along with the Sr isotopic ratio showing to be lower in the latter. There is influence of both vegetation and geology on the chemistry of the waters, which becomes quite evident in the difference between the Madeira river water, originating from the Andes, and that of its tributaries originating from the southern Amazonian stable cratonic environment, presenting low erosive capacity, therefore generating more diluted waters. Data shows the Madeira River’s bed sediments to be granulometrical, mineralogical and chemically distinct from those of its main affluents. Madeira River sediments are sandier, present larger quantity of quartz, lower content of Al2O3, Fe2O3, K2O, MgO, Na2O, TiO2, P2O5, MnO and trace elements, and their maturity increases downriver. Among tributary sediments, those from from the Machado and then Marmelos Rivers are the ones showing to be closer to Madeira River’s sediment composition, while Jamari sediments, with higher TiO2, Zr, Y, Nb, Ga, Hf, U, Ta and REE are the most distinct ones. Despite the intensive weathering and erosion environment, in the humid tropical conditions, to which rocks drained by Madeira River basin, are submitted to, Th/Co, Th/Pb, Th/Yb, Al/Pb, Zr/Co ratios and Pb isotopic composition values indicate distinct sources for the studied sediments. Madeira River sediments would originate mainly from mafic rocks, while tose from its tributaries would essentially have felsic rocks as their source.
Acesso aberto (Open Access)
Hidroquímica do rio Solimões na região entre Manacapuru e Alvarães: Amazonas - Brasil
(Instituto Nacional de Pesquisas da Amazônia, 2009) QUEIROZ, Maria Mireide Andrade; HORBE, Adriana Maria Coimbra; SEYLER, Patrick Thierry; MOURA, Candido Augusto Veloso
The present study evaluated the physical and chemical characteristics of the water of the rivers Solimões, Purus and their tributaries, collected in November of 2004 in the State of Amazonas between the cities of Manacapuru and Alvarães and Anamã and Pirarauara. Physical-chemical analyses (temperature, pH, electrical conductivity, turbidity, Ca2+, Na+, K+, Mg2+, HCO3-, SO42-, Cl-), and trace-elements (Li, B, Al, Sc, V, Cr, Mn, Fe, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Sb, Cs, Ba, Pb, La, Ce e U) and Sr isotopes were accomplished. The analyzed parameters and the chemical composition show that the waters of the rivers and tributaries of the central region of the Amazonia are chemically distinct between them. The white waters of Solimões are calcium-bicarbonate and of Purus are bicarbonates, and the respectives tributaries are sodium-potassium-bicarbonate and sodium-potassium-sulphate. This causes the white poorly acided waters to the neutrals and more conductives, while the black ones are less mineralized, more acids, mainly of Purus. The Ba, Sr, Cu, V e As in highest levels differentiate the Solimões white waters of the Purus`s waters, well as the tributaries of the first related to the second. This complex of caracteristics indicates that the Solimões as the Purus and their respectives tributaries are submitted to geological/ambiental distinct conditions. The influence of arrives in port of sediments of Andes is diluted at the currency of basin of the Solimões and it reflects on formation of fertile valleys Solimões and Purus. By another view, the crust rocks, represented by the Shields of the Guianas and Brasileiro both contribute, but in a reduced proportion.
Acesso aberto (Open Access)
Mineralogia e química dos sedimentos de fundo do médio e baixo Madeira e de seus principais tributários: Amazonas - Brasil
(Instituto Nacional de Pesquisas da Amazônia, 2011) QUEIROZ, Maria Mireide Andrade; HORBE, Adriana Maria Coimbra; MOURA, Candido Augusto Veloso
This study reports the granulometric, mineralogic and chemical analyses, including Pb isotope, carried out on the bottom sediments of the Madeira River, whose headwaters are in the Andes Mountain, and its tributaries that come from the cratonic region, in order to investigate the compositional variation of the sediments transported by the major rivers of the Amazon. The analytical data show that the bottom sediments of the Madeira River have higher amounts of sand and quartz, and lower contents of Al2O3, Fe2O3, K2O, MgO, Na2O, PF, TiO2O, P2O5, MnO and trace elements, and the maturity increases toward downstream. Among the tributaries, the bottom sediments from Machado and, secondarily, Marmelos rivers are those that more closely match the composition of the sediments of Madeira River. The sediments of Jamari River, with higher proportion of Ti2O, Zr, Y, Nb, Ga, Hf, U, Ta and REE, are quite distinct. In spite of the intense weathering and erosion, in humid tropical conditions, that the rocks drained by the Madeira river basin have been submitted, the Th/Co, Th/Pb, Th/Yb, Al/Pb, Zr/Co ratios and Pb isotope data indicate that different sources contributed to the bottom sediments. It is suggested that mafic rocks are the main source of the sediments of the Madeira River, while felsic rocks are the source of the tributaries.