Quantitative determination of hormites in typical saudi-arabian desert soils

To complement classical studies, standardless quantitative XRD phase analysis of Palygorskyte and Sepiolite, using new "SIROQUANT" computer software, was carried out on numerous samples of five typical desert soils (Takyr, Jimat, Tuwayq, Shifa, Hummock) from South-west Saudi Arabia. Particular emphasis is put on desert topsoil processes and their influence on the occurence of the fibrous clay minerals. This study aims at testing this method to find out if it is accurate enough to be used to determine if the soils fulfill the requirement (2% of palygorskite) of the YERMIC phase classification of the Revised Legend of The Soil Map of The World (FAO - UNESCO - ISRIC, 1988)