HAL: hal-00358585, version 1

DOI: 10.1016/j.geoderma.2008.09.010

IRD Horizon id: fdi:010044155

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Geoderma 148 (2008) 91-106

Soil morphological control on saline and freshwater lake hydrogeochemistry in the Pantanal of Nhecolândia, Brazil

Laurent Barbiero (  Corresponding author ) 1, A. T. Rezende Filho 2, S.A.C. Furquim 2, S. Furian 2, Arnaldo Y. Sakamoto 3, Vincent Vallès 4, Robert C. Graham 5, Monique Fort 6, Rosely P.D. Ferreira 2, José Pereira Queiroz Neto 2

For the Capes-Cofecub 412-03 collaboration(s)

(2008-10-21)

Joint pedological, geochemical, hydrological and geophysical investigations were performed to study the coexistence of saline and freshwater lakes in close proximity and similar climatic conditions in the Nhecolândia region, Pantanal wetlands in Brazil. The saline lakes are concentrically surrounded by green sandy loam horizons, which cause differential hydrological regimes. Mg-calcite, K-silicates, and amorphous silica precipitate in the soil cover, whereas Mg-silicates and more soluble Na-carbonates are concentrated in the topsoil along the shore of the saline lake. In saline solutions, some minor elements (As, Se) reach values above the water quality recommendations, whereas others are controlled and incorporated in solid phases (Ba, Sr). Locally, the destruction of the sandy loam horizons generates very acidic soil solution (pH ~ 3.5) through a process not yet understood. The soil distributions indicate that some freshwater lakes are former saline lakes. They are invaded by freshwater after destruction of the sandy loam green horizons, then the freshwater becomes enriched in K+, SO42-, Fe, Al, and a stream of minor and trace elements. The formation of these green sandy loam horizons in the saline environment and their destruction in the non-saline one emphasizes the dynamic nature of this environment.

1:	Laboratoire des Mécanismes et Transfert en Géologie (LMTG)
	CNRS : UMR5563 – Observatoire Midi-Pyrénées – Université Paul Sabatier [UPS] - Toulouse III – Institut de recherche pour le développement [IRD] : UMR154
2:	Laboratório de Pedologia, Departamento de Geografia
	Universidade Federal do Mato Grosso do Sul
3:	Departamento de Ciências Humanas
	Universidade Federal de Mato Grosso do Sul
4:	Laboratoire d'Hydrogéologie d'Avignon (LHA)
	Université d'Avignon : EA2665
5:	Department of Environmental Sciences
	University of California, Riverside
6:	Pole de recherche pour l'organisation et la diffusion de l'information géographique (PRODIG)
	CNRS : UMR8586 – Université Paris I - Panthéon-Sorbonne – Université Paris IV - Paris Sorbonne – Université Paris VII - Paris Diderot – Ecole Pratique des Hautes Etudes – Institut de recherche pour le développement [IRD] : UR215

Subject

:

Sciences of the Universe/Earth Sciences

Keyword(s): Alkalinity – sodicity – saline lake – soil hydrology – Nhecolândia – Pantanal – Brazil

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From: Andy Senegas <>

Submitted on: Tuesday, 3 February 2009 17:38:31

Updated on: Tuesday, 10 February 2009 18:36:12