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| Registros recuperados: 15 | |
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| SILVA, L. M. da; COSTA, R. de K. do N.; ALMEIDA, A. S. de; OLIVEIRA, C. H. A. de; ARAÚJO, E. A. de; TAVARES, O. C. H.; PEREIRA, M. G.; SANTOS, O. A. Q. dos. |
| No Acre, uma das características marcantes dos solos é a presença de minerais de argila do tipo 2:1, que confere padrões diferenciados de consistência em função do conteúdo de água. Esse comportamento implica em dificuldades no processo de amostragem e na avaliação de atributos físicos do solo, com destaque para a densidade do solo (Ds), atributo de grande relevância na avaliação do grau de compactação ou adensamento e componente do cálculo do estoque de nutrientes e carbono orgânico do solo. O objetivo deste estudo foi avaliar os métodos do anel volumétrico e do torrão parafinado na determinação da Ds em solos que apresentam argilas 2:1, em comparação a um solo de natureza caulinítica e oxídica, em horizontes superficiais e subsuperficiais. Não foi... |
| Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E) |
Palavras-chave: Densidade do solo; Método do torrão parafinado; Método do anel volumétrico; Paraffin clod method; Volumetric ring method; Fìsica del suelo; Análisis del suelo; Minerales arcillosos; Densidad del suelo; Acre; Amazônia Ocidental; Western Amazon; Amazonia Occidental; Física do Solo; Análise do Solo; Argila; Soil physics; Soil analysis; Soil density; Clay minerals. |
| Ano: 2020 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/1126449 |
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| Liu, Zhifei; Colin, Christophe; Huang, Wei; Le, Khanh Phon; Tong, Shengqi; Chen, Zhong; Trentesaux, Alain. |
| Results of clay mineralogy, major element geochemistry, and Sr and Nd isotopes in 93 argillaceous samples collected from drainage basins of the Pearl, Red, and Mekong rivers reveal different degrees of chemical weathering in Southeast Asia despite similar climate conditions across these regions. The kaolinite/illite ratio, illite chemistry index, and illite crystallinity can be used as indicators of chemical weathering intensity. These mineralogical proxies combined with the K(2)O/(Na(2)O + CaO) molar ratio, chemical index of alteration (CIA), and weathering trends observed from major element results indicate intensive silicate weathering in the Pearl River basin, moderate to intensive in the Mekong River basin, and moderate in the Red River basin.... |
| Tipo: Text |
Palavras-chave: Clay minerals; Major elements; Chemical weathering; Pearl River; Red River; Mekong River. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00235/34613/32949.pdf |
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| Lan, Xianhong; Zhang, Zhixun; Li, Rihui; Wang, Zhongbo; Chen, Xiaohui; Tian, Zhenxing. |
| Based on the clay minerals, content analysis from 187 stations in the surface sediments, this paper dealt with the assemblages and the distributions of clay minerals in the surface sediments off the Yangtze River estuary. The research results showed that the illite dominates the surface sediments off the Yangtze River estuary with the smectite or kaolinite the second rank and chlorite the third rank; the illite-smectite- kaolinite- chlorite-assemblage is the main type of the clay minerals assemblage in the area, with the illite-kaolinite-chlorite-smectite -type as the second rank; the source of clay mineral is mainly from the Yellow River and the Yangtze River. The Q-type cluster analysis show that sediments from both recent and ancient Yellow River were... |
| Tipo: Journal Contribution |
Palavras-chave: Clay minerals; Distribution. |
| Ano: 2012 |
URL: http://hdl.handle.net/1834/5849 |
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| Ksiezopolska,Alicja. |
| The mechanism of the formation of organomineral complexes in soils is very complex and still little known. Examination of the complexes in unaltered form, as isolated from the soil, is very difficult due to the dispersing effect of all extraction agents which break the complexes up, destroying their natural properties. It is much easier to perform most of the tests on preparations of organomineral complexes obtained under laboratory conditions. This paper is concerned with model research on the formation of synthetic complexes of humic acids with minerals: Na-montmorillonite, mica, kaolinite at various pH values (3-7) and in the presence of aluminum ions. The aim of the research was to develop an optimum reaction of suspension for the synthesis of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Humic acids; Clay minerals; Aluminum oxide; Degree of complex formation. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162005000200007 |
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| Santa Cruz, L.; Castro, D.; Sardiñas, O.. |
| Como parte del proyecto de implementación de la dieta macrobiótica en Cuba se valoró la situación de una arcilla italiana, empleada para enriquecer al agua potable con sales minerales, por una cubana similar (bentonita natural de Managua tipo 1). La caracterización minerológica, química y granulométrica de ambas arcillas fue similar. Se estudió el efecto de tres concentraciones de arcilla cubana en agua potable (0,1; 0,5 y 1 %) después de 24 h. Este tratamiento incrementó significativamente las concentraciones de sodio, magnesio y hierro y disminuyó las de calcio, cinc y cobre en el agua; todos los elementos cumplieron con las normas vigentes de agua potable. |
| Tipo: Journal Contribution |
Palavras-chave: Clay minerals; Water; Minerals; Food; Diets; Drinking water. |
| Ano: 2008 |
URL: http://hdl.handle.net/1834/5013 |
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| Pujos, M; Latouche, C; Maillet, N. |
| Marine muds deposited on the French Guiana coast mostly originate in the Amazon. Recent sediments are composed of (a) illite (33 %) and chlorite (13 %) of Andean mountain origin; and (b) kaolinite (28 %) and smectite (26 %), principally from the Amazonian lowlands but also from the Guiana Shield. In the coastal mud prism, high-resolution seismic profiles, together with sedimentological, micropaleontological and soil engineering studies, supplemented by C-14 dates, permitted a stratigraphic interpretation of eight cores. Three episodes have been determined on the basis of clay-mineral variations related to Amazonian lowland, Andean and Guiana shield sources. The older episodes 3 (3000-1700 y BP) and 2 (1700-1000 y BP) are predominantly characterized by... |
| Tipo: Text |
Palavras-chave: Late quaternary; French Guiana; Shelf; Clay minerals; ENSO. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00094/20506/18175.pdf |
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| Coronel, V.; Ayón, H.A.. |
| En este trabajo se presentan los resultados de los análisis térmico-diferenciales para la identificación de minerales de arcillas en el Archipiélago de Jambelí. La distribución de los minerales de arcilla refleja el área de influencia de los principales ríos que drenan áreas de diferente composición mineralógica. Las illitas están distribuídas en todo el Archipiélago. Las smectitas son abundantes en las zonas periféricas. Las cloritas están restringidas a las desembocaduras de los ríos que drenan terrenos metamórficos. La identificación de estos grupos mineralógicos coincide con la de otros estudios de otros autores que han utilizado difractometría de rayos X. |
| Tipo: Journal Contribution |
Palavras-chave: Clay minerals; Clay minerals; Http://aims.fao.org/aos/agrovoc/c_15836. |
| Ano: 1980 |
URL: http://hdl.handle.net/1834/2105 |
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| Vanderaveroet, P. |
| The clay fraction of sediments drilled at Ocean Drilling Program (ODP) sites 1071 and 1072 is composed of variable proportions of chlorite, illite, smectite. kaolinite, vermiculite and mixed-layers such as illite/vermiculite (I/V) and chlorite/vermiculite (C/V). Miocene and Pliocene climates allowed formation of vermiculite and kaolinite. Pleistocene clay sedimentation was characterized by abundant chlorite and illite resulting from increasing erosion of the crystalline rocks outcropping in northern areas (e.g. Canadian Shield) developed under glacial climate. The clay minerals identified on the shelf are relatively similar to those deposited on the New Jersey continental slope and rise, and a similar trend in the composition of clay assemblages is... |
| Tipo: Text |
Palavras-chave: Plate-forme; New Jersey; Minéraux argileux; Néogène; Paléoclimat; Shelf; New Jersey; Clay minerals; Neogene; Palaeoclimate. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00325/43575/44043.pdf |
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| Kaschuk,Glaciela; Santos,Julio Cesar Pires; Almeida,Jaime Antonio; Sinhorati,Deise Cristina; Berton-Junior,João Francisco. |
| Soil-feeding termites transport soil for mound building, and this process can affect soil characteristics. To verify the influence of soil termite activity on soil characteristics, samples were collected from top, bottom and center of termite mounds, and of the adjacent area, to assess chemical and physical properties and mineralogical composition. Four replicates of termite mounds and respective adjacent areas were randomly sampled in Lages, Capão Alto, Painel, São José do Cerrito and Coxilha Rica (State of Santa Catarina, southern Brazil). Results of chemical analyses showed a greater content of K, P, Ca, Mg and organic C in the inner part of termite mounds, accompanied by lower pH in relation to soil of the adjacent area. There were no differences... |
| Tipo: Info:eu-repo/semantics/report |
Palavras-chave: Chemical and physical soil properties; Clay minerals; Soil biology; Termite mounds. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000600013 |
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| Tudryn, Alina; Leroy, Suzanne A. G.; Toucanne, Samuel; Gibert-brunet, Elisabeth; Tucholka, Piotr; Lavrushin, Yuri A.; Dufaure, Olivier; Miska, Serge; Bayon, Germain. |
| This paper provides new data on the evolution of the Caspian Sea and Black Sea from the Last Glacial Maximum until ca. 12 cal kyr BP. We present new analyses (clay mineralogy, grain-size, Nd isotopes and pollen) applied to sediments from the river terraces in the lower Volga, from the middle Caspian Sea and from the western part of the Black Sea. The results show that during the last deglaciation, the Ponto-Caspian basin collected meltwater and fine-grained sediment from the southern margin of the Scandinavian Ice Sheet (SIS) via the Dniepr and Volga Rivers. It induced the deposition of characteristic red-brownish/chocolate-coloured illite-rich sediments (Red Layers in the Black Sea and Chocolate Clays in the Caspian Sea) that originated from the Baltic... |
| Tipo: Text |
Palavras-chave: Caspian sea; Black sea; SIS deglaciation; Early Khvalynian transgression; Chocolate clays; Red layers; Clay minerals; Neodymium isotopes; Pollen; Late Pleistocene. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00345/45605/45225.pdf |
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| Bayon, Germain; Delvigne, C.; Ponzevera, Emmanuel; Borges, A. V.; Darchambeau, F.; De Deckker, P.; Lambert, T.; Monin, L.; Toucanne, Samuel; Andre, L.. |
| The δ30Si stable isotopic composition of silicon in soils and fine-grained sediments can provide insights into weathering processes on continents, with important implications on the Si budget of modern and past oceans. To further constrain the factors controlling the distribution of Si isotopes in sediments, we have analysed a large number (n=50) of separate size-fractions of sediments and suspended particulate materials collected near the mouth of rivers worldwide. This includes some of the world’s largest rivers (e.g. Amazon, Congo, Mackenzie, Mississippi, Murray-Darling, Nile, Yangtze) and rivers from the case study areas of the Congo River Basin and Northern Ireland. Silt-size fractions exhibit a mean Si isotopic composition (δ30Si = -0.21 ± 0.19‰; 2... |
| Tipo: Text |
Palavras-chave: World rivers; Congo basin; Northern Ireland; Si isotopes; Clay minerals; Weathering; Temperature; Precipitation. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00434/54609/55991.pdf |
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| Registros recuperados: 15 | |
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