Skip to main content

Pedogenic formation of smectites in a vertisol developed from granitic rock from Kaélé (Cameroon, Central Africa)

Buy Article:

$12.96 plus tax (Refund Policy)

Smectite formation in a vertisol developed from a granitic parent rock in the Kaélé region of Cameroon in a tropical, dry climate was studied by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), chemical analyses, cation exchange capacity (CEC) and low temperature gas adsorption. The soil profile comprises three horizons (from base to top): (1) a saprolite, (2) an intermediate horizon, and (3) an upper dark grey horizon. In the saprolite, the progressive alteration of feldspars gave rise to the exclusive neoformation of beidellite exhibiting a typical honeycomb fabric. This process resulted in Al, Fe, Ca, Mg, Ti and Mn enrichment, a depletion of Si and Na and a significant negative Eu anomaly. In the upper horizons, beidellite evolves and is transformed into montmorillonite and kaolinite, probably through a series of smectitekaolinite mixed layers. This transformation, from the saprolite to the upper horizons, causes the observed decrease in the CEC and the increase in specific surface area and mesoporosity of the clay. The REE patterns of the bulk soil and clay fraction display similar behaviour, indicating that the three horizons, and hence the clay minerals, have a common source in the underlying granite. Mass-balance calculations show that the intense weathering of the granite leads to a mass reduction of ∼80–90%.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
No Metrics

Keywords: CAMEROON; GEOCHEMISTRY; GRANITE; KAELE; SMECTITES; VERTISOLS; WEATHERING; XRD

Document Type: Research Article

Publication date: 2007-12-01

More about this publication?
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
UA-1313315-23
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more