An Investigation on Clay Mineral Composition of the Loess Materials in the South Eastern Basin of the Caspian-Sea

Our investigation on the clay mineral compositions of the Loess materials in the NE of Iran, presents the following The main clay mineral components of the Loess materials in the area are illite and chlorite accompanied by lesser amount of kaolinite and expounding minerals such as smektite. However, with increasing moisture in Minoo-Dasht and Gorgan area, the content of kaolinite in the A-horizon increases to 25%, while smektite is still low and reaches to about 1-7% with traces of mixed layer minerals in all horizons. In contrast, in semiarid area under the steppic conditions, particularly in the B-horizons, the quantity of smektite increases to 15%. The traces of palygorskites in the loess materials of the area, indicates that the conditions for formation of the materials are not exceedingly arid and saline.