Formation and stability of imogolite in a tephritic Spodosol, Cascade Range, Washington, USA
- Univ. of California, Davis (USA)
- Univ. of Washington, Seattle (USA)
Chemical equilibrium modeling was used to examine the stability of imogolite in a Spodosol influenced by volcanic ash in the Cascade Mountains of Washington State. Imogolite was found to be a major component of the clay fraction in the Bs and C horizons of these soils. Soil solutions were collected during the fall, winter and spring from the major genetic horizons. Following fractionation of Al into inorganic and organic complexes, saturation indices for various minerals were calculated. Weathering in the E and Bhs horizons was dominated by organic acids and Al transport occurred primarily as Al-organo complexes. Soil solutions in these horizons were highly undersaturated with respect to imogolite solubility. Therefore, imogolite soils would not be expected to form in these horizons and participate in transport of Al to the lower soil horizons. Soil solutions from the Bs and C horizons appeared to be in equilibrium with both the hydroxy aluminous interlayer of 2:1 layer silicates and imogolite. The hydrous aluminous interlayer appeared to control Al activities while imogolite regulates H{sub 4}SiO{sub 4} activities. This pattern suggests that the availability of soluble H{sub 4}SiO{sub 4} may limit the formation and dissolution of imogolite. Imogolite is a metastable mineral in the Bs and C horizons and its formation may occur under the present weathering environment which is dominated by H{sub 2}CO{sub 3}.
- OSTI ID:
- 7164454
- Journal Information:
- Geochimica et Cosmochimica Acta; (USA), Journal Name: Geochimica et Cosmochimica Acta; (USA) Vol. 53:8; ISSN GCACA; ISSN 0016-7037
- Country of Publication:
- United States
- Language:
- English
Similar Records
Aluminum solubility control in different horizons of a podzol
Lithological controls on soil geochemistry and clay mineralogy across Spodosols in the coastal temperate rainforest of southeast Alaska
Related Subjects
580000* -- Geosciences
ACTIVATION ENERGY
ALUMINIUM COMPLEXES
ASHES
CASCADE MOUNTAINS
CHEMISTRY
COMPLEXES
DISSOLUTION
ENERGY
EQUILIBRIUM
FEDERAL REGION X
GEOCHEMISTRY
LEACHING
MINERALIZATION
MINERALOGY
MOUNTAINS
NORTH AMERICA
ORIGIN
RESIDUES
SEPARATION PROCESSES
SOIL CHEMISTRY
SOILS
SOLUBILITY
USA
VOLCANOES
WASHINGTON
WEATHERING