Occurrence of palygorskite in soils of ecija (Spain)

Abstract

Palygorskite has been characterized in soils classified as typic argixerolls, located in an extensive Quaternary zone in the north of Seville (Spain), where the geological and climaticconditions suggest its genesis. The soils contain a Ck horizon which has different texturalcharacteristics to the other horizons in the profiles. The presence of large white calcareousnodules and cristobalite is the principal difference between them. The formation of palygorskite at textural discontinuities is in agreement with the characteristics of these soils. Under the present conditions of the soils (pH, magnesiumand silicon concentration and soluble salts), the alteration of palygorskite to smectite issuggested. The sporadic nucleation of large fibres of palygorskite on silica crystal suggests that this latter mineral could provide the necessary silicon for palygorskite formation. © 1990, CSIRO. All rights reserved.