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| Ratie, G.; Quantin, C.; Maia De Freitas, A.; Echevarria, G.; Ponzevera, Emmanuel; Garnier, J.. |
| Ultramafic derived soils are characterized by low nutrient soils, a low Ca:Mg ratio, and high metal contents such as Ni, Co and Cr. The vegetation growing on these soils is highly adapted and includes both Ni hyperaccumulator and accumulator species. Today, approximately 530 Ni hyperaccumulator species are listed worldwide and the Ni concentration can be extremely high, e.g. up to 25% in latex from Pycnandra acuminata (Sapotaceae), a tree found in New Caledonia. The aim of this study is to identify the potential role of Ni hyperaccumulator plants in the Ni biogeochemical cycle at the soil surface by using Ni isotopes. A set of Ni hyperaccumulator and Ni accumulator plants as well as topsoils were sampled on the Barro Alto and Niquelândia ultramafic... |
| Tipo: Text |
Palavras-chave: Nickel; Isotope; Ni hyperaccumulator species; Ultramafic environment. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00464/57565/59740.pdf |
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| 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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