Effect of parent material on clay mineralogy in some woodland areas of Northern Iran

In order to evaluate the effects of parent material on clay mineralogy in northface of the Elborz mountain area that is covered with deciduous trees, five mountain physiographical units with dolomite, sandstone, marl, limestone and conglomera parent material were selected and in each physiographical unit some soil profiles were studied. Soil samples were taken from different horizons and leyers of the soil profiles. Morphological features of each soil profile were determined and soils were classified according to USDA soil taxonomy. The soil samples were analyzed by conventional methods and clay minerals were identified by X-ray diffraction analysis. This study indicated that montmorillonite, illite, vermiculite, cholorite and mica-smectite were dominant respectively in the soils that formed from dolomite. But in sandstone parent material soils, due to light texture and good drainage, the vemiculite, illite, montmorillonite, kaolinite and hydroxy intelayer vermiculite were dominant, respectively. In marl with high amounts of CaCO3, no leaching and translocation of clay, montmorillonite, illite, chlorite, vermiculite and mica-smectite clay minerals were dominant, respectively. In the soils formed from limestone, the accumulation of lime occurred in subsurface layers and clay minerals of illite, montmorillonite, vermiculite,chlorite, kaolinite and mica-vermiculite were present. Soils that have been formed on conglomerate parent material, were dominant in the order of illite, vermiculite, montmorillonite, chlorite and kaolinite, respectively.