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Contribuição à avaliação do goodwill: depósitos estáveis, um ativo intangível. ; Contribution to the valuation of goodwill: core deposits, an intangible asset.

Martins, Vinicius Aversari
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 06/02/2002 PT
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O presente trabalho tem como objetivo principal demonstrar que parcela da base de depositantes de instituições financeiras que se utilizam de depósitos (a prazo e a vista) como fonte de financiamento das suas atividades, identificada pelos depósitos estáveis, representa um ativo intangível da instituição depositária. Esse ativo intangível decorrente dos depósitos estáveis, quando passível de identificação específica, explica parte do goodwill da instituição depositária, pelo fato do goodwill ser um ativo residual dependente principalmente da avaliação da empresa como um todo. Sendo o valor do goodwill determinado pela diferença entre o fair value da entidade como um todo, como um ativo único em continuidade, e a soma algébrica dos fair values dos ativos líquidos identificáveis dessa entidade, à medida que novos ativos antes não contabilizados são identificados, está-se explicado a natureza do goodwill, assim como está-se auxiliando na sua atribuição de valor. Portanto a identificação de mais um ativo intangível das instituições financeiras implica na identificação de parcelas componentes do goodwill, que englobava esse ativo intangível antes da identificação do ativo intangível, assim como também implica na explicação econômica de parte do goodwill. Para que o objetivo pudesse ser alcançado...

Depósitos mercantis: um estudo das práticas contábeis dos depositários na comercialização de produtos agrícolas no estado do Paraná ; Mercantile deposits: a study of the accounting practices of the depositaries in the comercialization of agricultural products in the state of Paraná

Zanchet, Aladio
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 08/10/2004 PT
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O objetivo geral deste trabalho foi analisar e discutir a problemática da contabilização, pelos depositários, das operações de depósito mercantil de produtos agrícolas feitas por produtores junto as tradings e agroindústrias no estado do Paraná. Dos três enfoques específicos dados a esse objetivo, o primeiro buscou identificar e analisar as características dessas operações no sentido de avaliar se elas satisfazem os critérios contábeis para o seu reconhecimento nas demonstrações contábeis do depositário. O segundo buscou identificar a política contábil adotada em relação ao reconhecimento ou não dessas operações pelas tradings e agroindústrias do estado do Paraná, enquanto o terceiro tratou de identificar e analisar os critérios observados por essas empresas para a escolha da política contábil adotada. A amostra dos dados foi selecionada pelo método de Amostragem Intencional e foi constituída por um conjunto de dez empresas, listadas entre as que detêm a maior representatividade na comercialização de soja e milho no estado do Paraná. No conjunto, essas dez empresas representaram, na safra 2001/2002, 44,5% da comercialização da soja e 21,3% da comercialização do milho do estado do Paraná. A pesquisa empírica identificou três modalidades de depósito com as quais essas empresas operam...

Aloformação Paranavaí: depósitos coluviais quaternários da Bacia Hidrográfica do Alto Rio Paraná (SP, PR e MS); Paranavaí alloformation: quaternary colluvial deposits of Upstream Rio Paraná Hydrographic Basin (SP, MS e PR)

Sallun, Alethea Ernandes Martins
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/06/2007 PT
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Depósitos pleistocênicos arenosos de origem coluvial são encontrados em diversas regiões do Brasil, nos estados de São Paulo, Paraná e Mato Grosso do Sul. Associados a distintos contextos geológicos, esses depósitos têm recebido diferentes denominações como Formação Paranavaí (SP, PR e MS), Formação Piquerobi (SP) e Formação Cachoeirinha (MS). Neste contexto, foi possível individualizar sob pontos de vista sedimentológico, geocronológico e estratigráfico os depósitos quaternários que ocorrem na Bacia Hidrográfica do Alto Rio Paraná (SP, PR e MS) através da aloestratigrafia, propondo formalmente o Alogrupo Alto Rio Paraná, que é constituído de depósitos coluviais da Aloformação Paranavaí e depósitos fluviais da Aloformação Paraná. Os resultados obtidos indicam que o Alto Rio Paraná está ativo, no mínimo desde 1 Ma passados até os dias atuais, no afeiçoamento do relevo de formas construtiva (terraços) e destrutiva (dissecação). Esses registros geológicos testemunhariam importantes mudanças paleoclimáticas e/ou eventos neotectônicos, que modificaram os níveis de base e reafeiçoaram o relevo. Os episódios de agradação coluvial dos depósitos da Aloformação Paranavaí, instalados sobre superfícies peneplanizadas e afeiçoadas durante o Pleistoceno...

Distribuição dos depósitos de argilas cauliníticas brancas associadas à sistemas pedológicos Latossolo/Espodossolo na região amazônica: análise de imagens orbitais e estudos de campo; White kaolinitic clay deposits distribution associated with the Oxisol/Spodosol pedologic systems in the Amazon region: field studies and satellite images analysis

Pereira, Osvaldo José Ribeiro
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/09/2011 PT
Relevância na Pesquisa
36.79%
O presente trabalho teve como objetivo geral determinar a distribuição espacial de depósitos de argilas cauliníticas brancas na região de São Gabriel da Cachoeira, estado do Amazonas, por meio de estudos de campo e análise de imagens orbitais. Foram desenvolvidos estudos em duas escalas distintas. Um de detalhe, com coleta de amostras em uma área de 0,3km2 e com pontos de amostragem eqüidistantes de 50m, e outo regional em área de 65km2 com características geoambietais semelhantes àquelas observadas na zona de estudo detalhado. Buscou-se selecionar variáveis pedológicas (textura e cor do solo, concentração de óxidos e oxidróxidos de ferro), topográficas e fitofisionômicas relacionadas às possíveis ocorrências de depósitos de argilas cauliníticas brancas. Para a área de detalhe determinou-se a textura, a cor e a concentração de óxidos e oxidróxidos de ferro para os primeiros 100cm do solo. Os resultados obtidos foram mapeados e posteriormente associados aos dados de relevo, tipo de solo e vegetação local. A partir do estudo em escala local verificou-se que a textura do solo e a concentração de óxidos e oxidróxidos de ferro variam nos primeiros 100 cm de solo, na transição dos Latossolos para os Espodossolos. Foi possível verificar...

THE LONG-TERM EVOLUTION OF IMMUNE DEPOSITS IN PASSIVE HEYMANN NEPHRITIS

Soares, V. A.; Almeida, D. B.
Fonte: Associação Brasileira de Divulgação Científica (ABRADIC) Publicador: Associação Brasileira de Divulgação Científica (ABRADIC)
Tipo: Artigo de Revista Científica Formato: 149-159
ENG
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1. To study the long term course of passive Heymann nephritis (PHN), 42 adult male Wistar rats were injected with rabbit anti-FX1A serum (PHN group) and 42 rats received normal rabbit serum (control group). Two animals from each group were sacrificed 2 weeks after the inoculation and 10 animals each from the control and PHN groups were sacrificed 4, 13, 25 and 53 weeks later.2. The PHN group exhibited a significant elevation in 20-h proteinuria which lasted from the first week (control group, 9.19 +/- 0.87; PHN group, 25.3 +/- 2.66) to the 25th week (control group, 22.6 +/- 2.15; PHN group, 66.7 +/- 10.4) except for week 17. From week 29 to week 53 there was no statistical difference between the 2 groups.3. Light microscopy showed no difference between the kidneys of PHN and control rats. Immunofluorescence microscopy in PHN rats showed granular deposition of autologous and heterologous IgG on the glomerular basement membrane (GBM), whose intensity and pattern did not change during 53 weeks of observation.4. When examined by electron microscopy the glomeruli of PHN rats showed: a) electron-dense deposits which were initially subepithelial and homogeneous and later intramembranous, granular and often surrounded by an electron-transparent halo; b) focal thickening of the GBM at the sites of intramembranous deposits; c) effacement of podocytes located close to the deposits; d) penetration of the podocytes into the GBM associated with the deposits; e) presence of osmiophilic granules in the cytoplasm of the podocyte located inside the GBM similar to the granules of the deposits next to them. The association of the penetration of the podocytes into the GBM with the deposits and the presence of the osmiophilic granules inside the foot process have not been described previously in PHN.5. The results suggest that the podocytes play a role in the clearing of intramembranous deposits in PHN.

Metaturbidite-hosted gold deposits, Córrego do Sítio lineament, Quadrilátero Ferrífero, Brazil

Roncato Júnior,Jorge Geraldo; Lobato,Lydia Maria; Lima,Luiz Claudio; Porto,Cecília Germano; Silva,Rosaline Cristina Figueiredo e
Fonte: Sociedade Brasileira de Geologia Publicador: Sociedade Brasileira de Geologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2015 EN
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A study of geology and rocks paragenesis has been conducted at the Córrego do Sítio auriferous lineament, containing the Cachorro Bravo, Laranjeiras and Carvoaria metaturbidite-hosted lode-gold deposits located in the Quadrilátero Ferrífero Region, Minas Gerais, Brazil. These representative deposits are described to illustrate the essentially similar general character of all the deposits of lineament as well as the wide compositional and mineralogical differences in the ore of the different deposits, where, for the Cachorro Bravo deposit, a geological mapping included two underground mine galleries. The Córrego do Sítio unit is a metamorphosed turbidite in an alternating sequence of metagraywackes and phyllites, with parallel to discordant metamafic dikes and sills. The ore zone is predominantly hosted at the stratigraphic break between metasedimentary and metamafic rocks. Four deformation events affected the mine sequence. Mineralized veins and veinlets are considered to have formed within a brittle-ductile shear-zone environment and occurred in multiple episodes. Different vein types are recognized, but the most important volumetrically is a S1-concordant type characterized by smoky and milky quartz-carbonate-sulfide ± sulfosalts veins. Veins are dominated by quartz...

Are Deposits a Stable Source of Funding for Microfinance Institutions?

Abakaeva, Julia; Glisovic-Mezieres, Jasmina
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
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Poor people save. The conventional view is that low-income depositors transact more frequently than holders of larger accounts and are more prone to income disruptions from natural disasters, health issues, crime, and other factors. This perception makes financial institutions stepping into the under-served low-income space worry about whether they can use small deposits to fund their lending operations. But new research finds that under normal circumstances, aggregate balances for low-income accounts move gradually, and they are not prone to abrupt month-by month swings. This should make liquidity management easier because it gives the institutions enough time to adjust to changes in deposit supply over several months.

Financial Inclusion for Financial Stability : Access to Bank Deposits and the Growth of Deposits in the Global Financial Crisis

Han, Rui; Melecky, Martin
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
EN_US
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In crisis times, depositors get anxious, can run on banks, and withdraw their deposits. Correlated withdrawals of bank deposits could be mitigated if bank deposits are more diversified, that is, held by more individuals. This paper examines the link between the broader access to bank deposits prior to the 2008 crisis and the dynamics of bank deposit growth during the crisis, while controlling for relevant covariates. Employing proxies for access to deposits and the use of bank deposits, the authors find that greater access to bank deposits can make the deposit funding base of banks more resilient in times of financial stress. Policy efforts to enhance financial stability should thus not only focus on macroprudential regulation, but also recognize the positive effect of broader access to bank deposits on financial stability.

The genesis of gold-copper-bismuth deposits, Tennant Creek, Northern Territory

Skirrow, Roger
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Thesis (PhD); Doctor of Philosophy (PhD)
EN_AU
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The Au-Cu-Bi- deposits of the Proterozoic Tennant Creek Inlier share geological and geochemical characteristics that indicate strong links in their genesis, yet the diversity in alteration assemblages, metal ratios and zonation patterns reflect variations in ore forming processes that previously have not been explained in detail. The West Peko deposit is representative of Cu-rich, pyrrhotite-bearing mineralisation with intermediate gold grades, in magnetite+ hematite-rich syntectonic ‘ironstones’. By contrast, the high grade Eldorado Au deposit contains minor sulfides and very low Cu grades, similar to several of the larger gold producers in the field (e.g. Juno, White Devil, Nobles Nob), and is also hematite-rich. Au, Chalcopyrite and Bi-sulfosalts were introduced into pre-existing ironside during progressive shearing, either late in the first regional deformation event (D1) or during a second phase of deformation. The occurrence of some Au zones outside ironstones suggests the ore fluids in part followed different flow paths to hose of the ironside-forming fluids. Three chemically and isotopically distinct fluids have been characterised. (i) Ironstone-forming fluids at West Peko and Eldorado were Ca-Na-Cl (-Fe?) brines containing 12-20 weight % total dissolved salts...

Iron Deposits in Southwestern Indiana

Bundy, Wayne M.
Fonte: Indiana Geological Survey Publicador: Indiana Geological Survey
Tipo: Relatório Formato: 1716655 bytes; application/pdf
EN_US
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Indiana Geological Survey Report of Progress 10; Most of the iron deposits of Martin and Greene Counties, Ind. , are within the Mansfield formation (lower Pennsylvanian), but small deposits also occur in the Beech Creek limestone (upper Mississippian). Goethite, the major iron mineral, occurs as cementing material, concretions, bands along bedding planes, veins, irregular open-space fillings, and replacements of plants in sandstone and shale. Small replacement bodies of goethite are common in the limestone. Magnetite occurs as finely disseminated grains within the interior shells of concretions. Iron deposits in Indiana probably were precipitated in swamps and lagoons in early Pennsylvanian time. The belief that the iron was deposited in bogs is substantiated by the following evidence: (1) the irregular and local distribution of the iron deposits in Indiana is characteristic of bog iron deposits; (2) the relative abundance of those plant fossils associated with iron deposits is similar for both the iron deposits in Indiana and bog iron deposits; (3) the chemical analyses of the iron deposits in Indiana are similar to other iron deposits that are known to be of bog origin; (4) clay that is similar in composition to underclay (indicative of swamp conditions) is present in the Indiana deposits; and (5) the syngenetic nature of the concretions and the abundance of concretions of the Indiana deposits are like those of other iron deposits that are known to be of bog origin. Shrinkage cracks and colloform texture indicate that the iron was largely a colloidal precipitate. Electrolytes...

Extremely negative and inhomogeneous sulfur isotope signatures in Cretaceous Chilean manto-type Cu???(Ag) deposits, Coastal Range of central Chile

Carrillo-Ros??a, Javier; Boyce, Adrian J.; Morales-Ruano, Salvador; Morata, Diego; Roberts, Stephen; Munizaga, Francisco; Moreno-Rodr??guez, Ver??nica
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
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El art??culo original ha sido publicado por Ore Geology Reviews, de la Editorial Elsevier, disponible en: http://www.sciencedirect.com/science/article/pii/S0169136813001443 El enlace v??a DOI es: http://dx.doi.org/10.1016/j.oregeorev.2013.06.013; Chilean manto-type (CMT) Cu(-Ag) hydrothermal deposits share a characteristic association of volcano-sedimentary Jurassic to Lower Cretaceous host rocks, style of mineralization, ore and associated mineralogy and geochemistry, with ore grades typically >1%Cu, that make this family of deposits significant and interesting, both academically and economically. Although often stratabound, geological evidence supports an epigenetic origin for these deposits. We present a detailed stable isotope study of La Serena and Melipilla-Naltahua Lower Cretaceous deposits, central Chile, which reveals extremely negative ??34S values, to -50???, which are among the lowest values found in any ore deposit. In addition, the range of ??34S values from sulfides in the two areas is very wide: -38.3 to -6.9??? in La Serena, and -50.4 to -0.6??? in Melipilla-Naltahua. These new data significantly extended the reported range of ??34S data for CMT deposits. Co-existing sulfates range from 7.9 to 14.3???, and are exclusive to La Serena deposit. The wide sulfide isotopic range occurs at deposit and hand specimen scale...

Luminescence dating of spring mound deposits in the southwestern Great Artesian Basin, northern South Australia

Prescott, J.; Habermehl, M.
Fonte: Taylor & Francis Ltd. Publicador: Taylor & Francis Ltd.
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
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Artesian spring mound deposits in the southwestern part of the Great Artesian Basin arise from groundwater discharge from flowing springs in the southern and western margins which reaches the surface through faults and weaknesses in thin confining beds overlying the Mesozoic artesian aquifers. Carbonate in solution in the artesian groundwater is deposited by many springs as tufa, building 'spring mounds.' Active flowing and dry inactive spring mounds occur in a variety of sizes and shapes. The ages of a representative selection of spring mound deposits have been found by luminescence dating of quartz sand grains that have been incorporated in the mound deposits. The spring deposits of the active flowing springs, Big Bubbler, Blanche Cup and Beresford Spring have ages of 15.1 ± 2.2, 10.9 ± 1.5 and 13.9 ± 1.0 ka, respectively. Spring complexes with both active flowing and dry extinct mounds, Strangways and Beresford Springs, have ages of 60 ± 8 and 219 ± 35 ka, respectively. Spring deposits of springs which ceased flowing and are overlying pedestals of Cretaceous Bulldog Shale and of substantial height (up to >45 m above the surrounding plain) of Beresford Hill and Kewson Hill gave ages of 128 ± 33 ka and 400 ± 100 ka, respectively. Elizabeth Springs is a large spring mound...

FLUID EVOLUTION AND STRUCTURAL CONTROL ON URANIUM DEPOSITS IN SUCCESSOR BASINS IN NORTHERN CANADA AND NORTHERN AUSTRALIA

Dieng, SERIGNE
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
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Uranium deposits associated with Paleoproterozoic successor basins were investigated using structural, petrographic, geochronological and geochemical relationships to understand the character and timing of ore-forming fluids and the structural control on uranium mineralization. The work focused on two successor basins that share similar geological characteristics: the Martin Lake Basin in the Beaverlodge area in Canada, and the El Sherana Basin in the South Alligator River area in Australia. The Beaverlodge area records six temporally distinct stages of U mineralization spatially associated with the Martin Lake successor basin. Early minor stages are hosted in cataclasite and veins at ca. 2.29 Ga and in albitized granite in the Gunnar deposit between ca. 2.3 Ga and 1.9 Ga, which predates the main stage of U mineralization of hydrothermal breccias that formed at ca. 1.85 Ga. Later stages of mineralization are related to minor veins at ca. 1.82 Ga linked to alkaline mafic dikes associated with the Martin Lake Basin and to minor veins at ca. 1.62 Ga corresponding to the timing of unconformity-type U mineralization in the overlying Athabasca Basin. The main breccia-type U mineralizing event that affected all deposits in the Beaverlodge area formed at ca. 1.85 Ma from metamorphic fluids at ca. 330oC linked to metasomatism during regional metamorphism of the Trans-Hudson Orogen. The ore-forming fluids were likely derived from metamorphic remobilization of pre-existing U-rich basement rocks...

Estratigrafía, sistemas depositacionales y aspectos composicionales del relleno neógeno de la cuenca Rodeo-Iglesia, San Juan, Argentina; Stratigraphy, depositional systems and compositional aspects of the neogene deposits of the Rodeo-Iglesia basin, San Juan province, Argentina

Alonso, María Susana
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2011 SPA
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En este trabajo se estudió el relleno neógeno de la Cuenca de Rodeo- Iglesia, que comprende una potente sucesión continental. Estos depósitos pueden separarse en dos formaciones, Cuesta del Viento y Rodeo. La primera es una nueva unidad, definida originalmente para la vecina Cuenca de La Tranca, que registra la sedimentación proximal relacionada directamente con el levantamiento de la Sierra Negra. En este trabajo, se propone la separación de los términos basales de la secuencia neógena, anteriormente asignados a la Formación Rodeo y su nueva asignación a la Formación Cuesta del Viento. Esta unidad corresponde a depósitos de sistemas proximales, de alta pendiente y energía y a intervalos pelíticos y areno-pelíticos, correspondientes a una sedimentación distal de sistemas que drenan desde el Oeste. La Formación Rodeo ha sido dividida en dos Miembros: Lomas del Campanario, conformado por depósitos relacionados con actividad volcánica intracuencal y su retrabajo y Las Flores, que registra el impacto sobre la cuenca del levantamiento de la Cordillera de Colanguil, y la consecuente progradación de cuñas clásticas Hacia el techo de la unidad, un episodio evaporítico de importancia ha dado origen a depósitos de yeso de espesores considerables. El Miembro Lomas del Campanario...

Extremely negative and inhomogeneous sulfur isotope signatures in Cretaceous Chilean manto-type Cu–(Ag) deposits, Coastal Range of central Chile

Moreno Rodríguez, Verónica; Morales Ruano, Salvador; Morata Céspedes, Diego Antonio; Roberts, Stephen; Munizaga Villavicencio, Francisco Javier; Boyce, Adrián J.; Carrillo Rosua, Javier
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo de revista
EN
Relevância na Pesquisa
36.82%
Artículo de publicación ISI; Chilean manto-type (CMT) Cu(–Ag) hydrothermal deposits share a characteristic association of volcanosedimentary Jurassic to Lower Cretaceous host rocks, style of mineralization, ore and associated mineralogy and geochemistry, with ore grades typically N1%Cu, that make this family of deposits significant and interesting, both academically and economically. Although often stratabound, geological evidence supports an epigenetic origin for these deposits. We present a detailed stable isotope study of La Serena and Melipilla–Naltahua Lower Cretaceous deposits, central Chile, which reveals extremely negative δ34S values, to −50‰, which are among the lowest values found in any ore deposit. In addition, the range of δ34S values from sulfides in the two areas is very wide: −38.3 to −6.9‰ in La Serena, and −50.4 to −0.6‰ in Melipilla–Naltahua. These new data significantly extended the reported range of δ34S data for CMT deposits. Co-existing sulfates range from 7.9 to 14.3‰, and are exclusive to La Serena deposit. The wide sulfide isotopic range occurs at deposit and hand specimen scale, and suggests a polygenic sulfur source for these deposits, where bacteriogenic sulfide dominates. While sulfur isotope data for the bulk of Jurassic CMT deposits...

Atacamite formation by deep saline waters in copper deposits from the Atacama Desert, Chile: evidence from fluid inclusions, groundwater geochemistry, TEM, and Cl-36 data

Leybourne, M. I.; Zúñiga Páez, Alejandro Andrés; Fehn, U.; Palacios Monasterio, Carlos Eugenio; Cameron, E. M.; Parada Reyes, Miguel Ángel; Reich Morales, Martín Herbert
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artículo de revista
EN
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Artículo de publicación ISI; The presence of large amounts of atacamite in oxide zones from ore deposits in the Atacama Desert of northern Chile requires saline solutions for its formation and hyperarid climate conditions for its preservation. We investigated the nature and origin of atacamite-forming solutions by means of coupling groundwater geochennical analyses with fluid inclusion data, high-resolution mineralogical observations, and chlorine-36 (Cl-36) data in atacamite from the Mantos Blancos and Spence Cu deposits. In both deposits, the salinities of fluid inclusions in atacamite are comparable to those measured in saline groundwaters sampled from drill holes. The average salinity of fluid inclusions in atacamite for the Mantos Blancos and Spence deposits (similar to 7-9 and 2-3 wt.% NaCleq, respectively) are strongly correlated to the salinities at which gypsum supersaturates from groundwaters in both deposits (total dissolved solids similar to 5-9 and 1-3 wt.% NaCl,9, respectively). This correlation is confirmed by transmission electron microscopy observations of atacamite-bearing samples, revealing an intimate association between atacamite and gypsum that can be traced down to the nanometer scale. Cl-36 data in atacamite provide new lines of evidence concerning the origin and age of the saline waters that formed atacamite in various stratabound and porphyry Cu deposits from the Atacama Desert. All atacamite samples show very low Cl-36-to-Cl ratios (11 x 10(-15) to 28 x 10(-15) at at(-1))...

Evidence for long-term uplift on the Canary Islands from emergent Mio–Pliocene littoral deposits

Meco, Joaquín; Scaillet, Stéphane; Guillou, Hervé; Lomoschitz, Alejandro; Carracedo, Juan Carlos; Ballester, Javier; Betancort, Juan Francisco; Cilleros, Antonio
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 2373 bytes; 2316077 bytes; text/plain; application/pdf
ENG
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13 pages, 9 figures, 1 table.-- Printed version published Jun 2007.; Several islands in the Canarian archipelago show marine deposits with identical fossil faunas, which are generally assigned to different glacioeustatic marine episodes: mainly Pleistocene episodes in Lanzarote and Fuerteventura, and Mio–Pliocene ones in Gran Canaria.; Three fossil species (Saccostrea chili, Nerita emiliana and Strombus coronatus) characterize all the marine deposits from southern Lanzarote, to the west and south of Fuerteventura and northeast of Gran Canaria. Three other species (Ancilla glandiformis, Rothpletzia rudista and Siderastraea miocenica) confirm the chronostratigraphic attribution of these deposits. Other more occasional fossils (as Chlamys latissima, Isognomon soldanii and Clypeaster aegyptiacus) fit an upper Miocene and lower Pliocene age. This agrees with new K/Ar ages obtained from pillow lavas emplaced into the marine deposits (ca. 4.1 Ma in Gran Canaria, ca. 4.8 Ma in Fuerteventura) and from underlying (ca. 9.3 Ma in Gran Canaria) or overlying (ca. 9.8 Ma in Lanzarote) lava flows.; The marine deposits are eroded but large continuous segments are preserved sloping gently towards the coast. Variations in the highest and the lowest elevations of the deposits apsl (above present sea level) indicate post-depositional uplift movements. Glacioeustatic causes are unlikely to be responsible for these variations on the basis of the coastal location of the deposits and their equatorial fauna characteristic of Mio–Pliocene corals. Differential uplift of the deposits across the archipelago is argued to result from the progressive seaward tilting of the islands along the insular volcanic trail marking the westward migration of hot spot head since 20 Ma. Successive westward accretion of younger volcanic edifices resulted in increasing lithostatic load of the crust with progressive (diachronous) tilting of the older edifices and their palaeo-shorelines marked by past coastal deposits.

Caesium-137 dating applied to slackwater flood deposits of the Llobregat River, NE Spain

Thorndycraft, V. R.; Benito, Gerardo; Walling, D. E.; Sopeña, Alfonso; Sánchez Moya, Yolanda; Rico, María Teresa; Casas Planes, M. A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 5160 bytes; image/gif
ENG
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14 páginas, 6 figuras, 1 tabla.-- El PDF del artículo es su versión post-print.; During a palaeoflood study of the Llobregat River (NE Spain), analysis of 137Cs was carried out on slackwater flood deposits to obtain an improved flood chronology for the most recent flood sediments. At the Monistrol study reach, 137Cs was measured in flood deposits preserved in valley side rock alcoves, with a range of 137Cs concentrations of 2.80–10.06 mBq/g measured. The 137Cs was associated with sediment mobilised from the upstream catchment by erosion and transported to the alcoves during floods. The onset of measured caesium activity in the sedimentary profiles permitted the deposits to be divided between those from floods that occurred before the mid-1950s and those from events after this period. Combining the information derived from the slackwater flood stratigraphy, the minimum discharge estimates associated with the flood deposits, 137Cs analysis and the instrumental peak discharge series, it was possible to identify the particular flood events responsible for the majority of the slackwater flood units. At Vilomara, however, 137Cs activity was measured in palaeoflood deposits dated to the Late Bronze Age and located at an elevation not reached by the floodwaters of the largest modern events. The data from this site indicated that the 137Cs was not associated with sediments transported by floods but was rainfall-derived...

Sedimentology of high-stage flood deposits of the Tagus River, Central Spain

Benito, Gerardo; Sánchez Moya, Yolanda; Sopeña, Alfonso
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
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This paper details the sedimentology of high-stage flood deposits, with the definition of sedimentary environments and their characteristic sequences, along two bedrock reaches of the Tagus River (Central Spain). High-stage flood deposits accumulated in bedrock canyons include slackwater flood deposits (SWD) and other types of deposits located at flow separation zones and associated with slow-moving flow (<1 m s−1). These flood deposits are common indirect indicators of flood stages used in palaeoflood studies for estimating the discharges associated with Quaternary floods. Depositional environments of flood deposits include (1) channel widening, (2) canyon expansion, (3) bedrock obstacles, and (4) backflooded areas along tributary streams. These flood deposits can be found associated with other non-fluvial environments, namely aeolian reworked and slope washflow facies. Channel widening, due to flood stage variations, comprises internal and external zones of the channel margins, and their characteristic sequences contain similar facies to those of alluvial floodplains. Canyon expansion environments favour vertical accretion of slackwater units and the development of flood deposit benches, which contain four sequences related to bench elevation and distance from the channel's main thread of flow. At the lee side of bedrock obstacles...

Depósitos quaternários no Parque Nacional Serra da Capivara e circunvizinhanças, Sudeste do Piauí, Brasil; Quaternary deposits in the Serra da Capivara National Park and surrounding area, Southeastern Piauí state, Brazil

Santos, Janaina C.; Barreto, Alcina Magnólia Franca; Suguio, Kenitiro
Fonte: Universidade de São Paulo. Instituto de Geociências Publicador: Universidade de São Paulo. Instituto de Geociências
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; Formato: application/pdf
Publicado em 01/12/2012 ENG
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No Parque Nacional Serra da Capivara e nas circunvizinhanças, na região Sudeste do Piauí, no Brasil, foram realizados estudos morfoestratigráficos, sedimentológicos e geocronológicos de depósitos superficiais para a interpretação de eventos paleoambientais, principalmente paleoclimáticos quaternários. Os depósitos sedimentares associados às unidades morfoestruturais são: leques coluviais no Vale da Serra Branca; depósitos elúvio-coluviais no Reverso da Cuesta e depósitos coluviais do Patamar Estrutural. Fora do Parque Nacional Serra da Capivara ocorrem também colúvios e depósitos aluviais do Rio Piauí. Muitos depósitos coluviais e aluviais são contemporâneos e indicativos de clima semiárido. De acordo com datações obtidas por luminescência (termoluminescência e luminescência opticamente estimulada), a evolução da paisagem atual iniciou-se há no mínimo 436 ± 51,5 ka, quando o rio Piauí depositou sedimentos argilosos. Entre 296,55 ± 46,95 ka e 114,8 ± 14,2 ka, o canal fluvial deste rio exibia provavelmente padrão entrelaçado e depositava barras de areia e cascalhos. Areias e lamas penecontemporâneas, com idades entre 202,75 ± 32,81 ka, 135 ± 16,4 ka e 117 ± 14,5 ka, foram depositadas nas vertentes do Parque Nacional da Serra da Capivara. Novo episódio de coluviação ocorreu entre 84...