Chemical weathering of crystalline rocks in the catchment area of acidic Ticino lakes, Switzerland

Rudolf Giovanoli; Jerald L. Schnoor; Laura Sigg; Werner Stumm; Juerg Zobrist

doi:10.1346/CCMN.1988.0360605

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Chemical weathering of crystalline rocks in the catchment area of acidic Ticino lakes, Switzerland

Journal article

Peer reviewed

Chemical weathering of crystalline rocks in the catchment area of acidic Ticino lakes, Switzerland

Rudolf Giovanoli, Jerald L. Schnoor, Laura Sigg, Werner Stumm and Juerg Zobrist

Clays and clay minerals, Vol.36(6), pp.521-529

12/1988

DOI: 10.1346/CCMN.1988.0360605

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Abstract

Atmospheric acidic deposition introduces hydrogen ions to terrestrial and aquatic ecosystems, which become partially neutralized by chemical weathering. In the southern Alps of Switzerland, small catchments containing little or no soil and lacking carbonate minerals represent sensitive hydrological settings in which the relationship between alteration of granitic gneiss by acid deposition and the resulting composition of lake waters can be studied. Transmission and scanning electron microscopy, coupled with X-ray powder diffraction of lake sediments from such areas showed mainly unaltered minerals from parent rocks and no secondary silicate minerals. Element mapping indicated noncrystalline aluminum hydroxide as a product of the chemical weathering of silicates. Noncrystalline iron hydroxide was also observed. Mass balance calculations and the stoichiometry of suitable chemical reactions representing the weathering processes were used to derive a plausible reaction sequence on the interaction of the predominant reactive rock minerals with acid precipitation that accounted for the measured chemical composition of the acid lakes.

Clay Mineralogy

Europe

Geochemistry

Petrology

Switzerland

Weathering

alteration

areal studies

Central Europe

chemical properties

chemical weathering

clay minerals

crystalline rocks

lacustrine environment

oxidation

reduction

Sedimentary petrology

sheet silicates

silicates

Ticino Switzerland

Details

Title: Subtitle: Chemical weathering of crystalline rocks in the catchment area of acidic Ticino lakes, Switzerland
Creators: Rudolf Giovanoli - Univ. Bern, Inst. Inorg. Chem. Bern CHE Switzerland
Jerald L. Schnoor - University of Iowa, Civil and Environmental Engineering
Laura Sigg
Werner Stumm
Juerg Zobrist
Resource Type: Journal article
Publication Details: Clays and clay minerals, Vol.36(6), pp.521-529
Publisher: Clay Minerals Society
DOI: 10.1346/CCMN.1988.0360605
ISSN: 0009-8604
eISSN: 1552-8367
Language: English
Date published: 12/1988
Academic Unit: Civil and Environmental Engineering; Occupational and Environmental Health
Record Identifier: 9983557373102771

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