بررسی زمین شیمی وکانی شناسی خاک آجرپزی وآجرتولیدی، دشت کوارومرودشت ، استان فارس

Kavar plain (۴۰ Km SE of Shiraz city) and Marvdash plain (۴۵ Km NE of Shiraz city) with abundant alluvial clay, are two important sources of brick clay in Fars province. According to the geochemical surveys,SiO_۲ , CaO, Al_۲O_۳ , Fe_۲O_۳ and Mgo are the most abundant elements in these clays and bricks made from them. Mineralogical analyses by X-ray diffraction (XRD) indicate that the major minerals in these samples are Quartz, Calcite, Dolomite, Montmorillonite,Chlorite, Orthoclase, Albite and Moscovite. Major minerals in baked bricks are Augite and Wollastonite .Comparison of the chemical analysis and standard chemical composition of brick clay indicate that these clays are unsuitable for brick making. Investigation of mineralogical composition ( by XRD) and predicted minerals by ternary systems of  SiO_۲- Al_۲O_۳- CaO, SiO_۲- Al_۲O_۳ –K_۲O, and SiO_۲- Al_۲O_۳- MgO, demonstrate this. Low clay and quartz content, results in low strength and formatting of the brick. High calcite content, results in the formation   Augite and Wollastonite, and inhibit formation of other minerals such as An, Fs and En.  Despite common belief and long time use of these clays, these clays are unsuitable for brick making and substitution by suitable formation clays , is recommended.