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Registros recuperados: 11
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Controls on Holocene denudation rates in mountainous environments under Mediterranean climate ArchiMer
Molliex, S.; Jouet, Gwenael; Freslon, Nicolas; Bourles, D. L.; Authemayou, C.; Moreau, Julien; Rabineau, Marina.
The Mediterranean domain is characterized by a specific climate resulting from the close interplay between atmospheric and marine processes and strongly differentiated regional topographies. Corsica Island, a mountainous area located in the western part of the Mediterranean Sea is particularly suitable to quantify regional denudation rates in the framework of a source-to-sink approach. Indeed, fluvial sedimentation in East-Corsica margin is almost exclusively limited to its alluvial plain and offshore domain and its basement is mainly constituted of quartz-rich crystalline rocks allowing cosmogenic nuclide Be-10 measurements. In this paper, Holocene denudation rates of catchments from the eastern part of the island of Corsica are quantified relying on in...
Tipo: Text Palavras-chave: Be-10-derived denudation rates; Schmidt Hammer; Quaternary; Quantitative geomorphology; Weathering.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00380/49082/49655.pdf
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Environmental Hf–Nd isotopic decoupling in World river clays ArchiMer
Bayon, Germain; Skonieczny, Charlotte; Delvigne, Camille; Toucanne, Samuel; Bermell, Sylvain; Ponzevera, Emmanuel; Andre, Luc.
The hafnium and neodymium radiogenic isotope systems behave differently during Earth surface processes, causing a wide dispersion of Hf and Nd isotopic compositions in sediments and other sedimentary rocks. The decoupling between Hf and Nd isotopes in sediments is generally attributed to a combination of preferential sorting of zircon during sediment transport and incongruent weathering processes on continents. In this study, we analysed size-fractions of sediment samples collected near the mouth of 53 rivers worldwide to better understand the factors controlling the distribution of Hf and Nd isotopes in sediments. Our results for rivers draining old cratonic areas and volcanic provinces demonstrate that both granite and basalt weathering can lead to...
Tipo: Text Palavras-chave: Hafnium isotopes; Neodymium; Rivers; Clays; Weathering; Climate.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00310/42094/41479.pdf
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Evolution of the physical and physiological quality of soybean seeds during processing. Repositório Alice
MOREANO, T. B.; MARQUES, O. J.; BRACCINI, A. L.; SCAPIM, C. A.; FRANÇA-NETO, J. B.; KRZYZANOWSKI, F. C..
bitstream/item/191342/1/Moreano-Evolution-open.pdf
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Soja; Glycine Max; Dano Mecânico; Praga de Planta; Umidade; Deterioração; Beneficiamento; Soybeans; Seed quality; Mechanical damage; Plant pests; Weathering.
Ano: 2018 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1104801
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Ge and Si isotope signatures in rivers: A quantitative multi-proxy approach ArchiMer
Baronas, J. Jotautas; Torres, Mark A.; West, A. Joshua; Rouxel, Olivier; Georg, Bastian; Bouchez, Julien; Gaillardet, Jerome; Hammond, Douglas E..
Solutes derived from the dissolution of silicate minerals play a key role in Earth’s climate via the carbon and other biogeochemical cycles. Silicon (Si) is a unique constituent of silicate minerals and a biologically important nutrient, so tracing its behavior in near-surface environments may provide important insights into weathering processes. However, Si released by weathering is variably incorporated into secondary mineral phases and biota, obscuring signals derived from primary weathering processes. Due to chemical similarities, Germanium (Ge) may help better understand the Si cycle and its relationship to chemical weathering. With this aim, we report new measurements of the concentration and isotopic composition of Ge for both the dissolved and...
Tipo: Text Palavras-chave: Germanium; Silicon; Isotopes; Rivers; Weathering; Fractionation.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00460/57196/59370.pdf
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Iron isotope systematics in Arctic rivers ArchiMer
Escoube, Raphaelle; Rouxel, Olivier; Pokrovsky, Oleg S.; Schroth, Andrew; Holmes, Robert Max; Donard, Olivier F. X..
The input of iron to the Arctic Ocean plays a critical role in the productivity of aquatic ecosystems and is potentially impacted by climate change. We examine Fe isotope systematics of dissolved and colloidal Fe from several Arctic and sub-Arctic rivers in northern Eurasia and Alaska. We demonstrate that the Fe isotopic (δ56Fe) composition of large rivers, such as the Ob’ and Lena, has a restricted range of δ56Fe values ca.–0.11 ± 0.13‰, with minimal seasonal variability, in stark contrast to smaller organic-rich rivers with an overall δ56Fe range from–1.7 to + 1.6‰. The preferential enrichment with heavy Fe isotopes observed in low molecular weight colloidal fraction and during the high-flow period is consistent with the role of organic complexation of...
Tipo: Text Palavras-chave: Iron isotope; Colloids; River; Weathering; Arctic; Iron speciation.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00273/38402/36865.pdf
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Método integrado de caracterização mineralógica de solos profundamente intemperizados. Infoteca-e
MARTINS, E. de S..
2000
Tipo: Comunicado Técnico (INFOTECA-E) Palavras-chave: Cerrado; Solo; Mineralogia; Intemperismo; Metodologia; Mineralogy; Methods; Weathering; Soil.
Ano: 2000 URL: http://www.infoteca.cnptia.embrapa.br/handle/doc/558084
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Nickel distribution and isotopic fractionation in a Brazilian lateritic regolith: coupling Ni isotopes and Ni K-edge XANES. ArchiMer
Ratie, G.; Garnier, J.; Calmels, D.; Vantelon, D.; Guimaraes, E.; Monvoisin, G.; Nouet, J.; Ponzevera, Emmanuel; Quantin, C..
Ultramafic (UM) rocks are known to be nickel (Ni) rich and to weather quickly, which makes them a good candidate to look at the Ni isotope systematics during weathering processes at the Earth’s surface. The present study aims at identifying the Ni solid speciation and discussing the weathering processes that produce Ni isotope fractionation in two deep laterite profiles under tropical conditions (Barro Alto, Goiás State, Brazil). While phyllosilicates and to a lower extent goethite are the main Ni-bearing phases in the saprolitic part of the profile, iron (Fe) oxides dominate the Ni budget in the lateritic unit. Nickel isotopic composition (δ60Ni values) has been measured in each unit of the regolith, i.e., rock, saprock, saprolite and laterite (n=52)....
Tipo: Text Palavras-chave: Nickel cycle; Lateritic regolith; Nickel isotopes; XANES; Ultramafic environment; Weathering.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00436/54712/56149.pdf
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Nickel isotope fractionation during tropical weathering of ultramafic rocks ArchiMer
Ratie, G.; Jouvin, D.; Garnier, Julien; Rouxel, Olivier; Miska, S.; Guimaraes, E.; Cruz Vieira, L.; Sivry, Y.; Zelano, I.; Montarges-pelletier, E.; Thil, F.; Quantin, C..
Although Ni isotopes have been shown to be significantly fractionated in terrestrial samples, their use in continental environmental studies has not yet been evaluated. The present study focuses on an ultramafic (UM) massif (Barro Alto, Goias, Brazil) because such areas are naturally rich in Ni. We present developed lateritic weathering profiles. The goal of the study is to evaluate the potential of using Ni isotopes in environmental continental studies by combining its isotopic signature with mineralogy, in order to better understand the geochemical cycling of Ni in UM settings during weathering. As such, Ni isotope values were measured in samples from the Barro Alto UM complex in the main stages of the lateritic weathering profile of UM rocks, including...
Tipo: Text Palavras-chave: Nickel; Isotope; Weathering; Mineralogy; Soil.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00254/36553/35098.pdf
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Revisão de intemperismo de micas. Infoteca-e
MARTINS, J. C.; MARTINS, E. de S.; REATTO, A..
ABSTRACT: The micas are rock forming mineral of the phyllosillicates group. The weathering of these minerals is fundamental in the understanding of potassium, silicon and magnesium liberation processes to the soil. the existent studies shown that the main factors that control the micas weathering are the pH of the solutions, the temperature, the size of the particles and the superficial area. The micas weathering is incongruous, in other words, always new minerals are formed as dissolution products, as vermiculite, kaolinite and goethite. These products can precipitate in the surface of the mica, especially the iron oxides of iron, and they impede the contact with its surface, reducing the dissolution kinetics. The structure of the micas is also a decisive...
Tipo: Documentos (INFOTECA-E) Palavras-chave: Mineralogia; Solo; Dissolução mineral; Intemperismo; Modelo experimental; Mineralogy; Soil; Mineral dissolution; Weathering; Experimental models.
Ano: 2004 URL: http://www.infoteca.cnptia.embrapa.br/handle/doc/568958
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The provenance of sediments in the Gulf of Lions, western Mediterranean Sea ArchiMer
Revillon, Sidonie; Jouet, Gwenael; Bayon, Germain; Rabineau, Marina; Dennielou, Bernard; Hemond, Christophe; Berne, Serge.
In this study, we undertook a reconnaissance study of sediments provenance in the Gulf of Lions focusing over the last 16 ka. We used geochemical and isotopic tracers to determine the source of sediments and give insight into the weathering conditions prevailing. Sediments samples were selected both onshore and offshore from the western, eastern, and central part of the Gulf of Lions. We analyzed bulk sediments, coarse and fine silt, and clay fractions. Elemental and Nd isotope compositions appeared to differ from one grain size fraction to another one. These are interpreted in terms of zircon addition in the coarse silt fraction for the elemental concentrations and variable sources influences for the Nd isotope compositions. Our results indicate that...
Tipo: Text Palavras-chave: Geochemistry; Provenance; Sediment; Weathering.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00043/15376/12734.pdf
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The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology ArchiMer
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
Registros recuperados: 11
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