MINERALOGICAL INSIGHTS INTO SOIL FORMATION: A CASE STUDY OF THE MARAND REGION, IRAN

Parent material is considered as the most important soil forming factor in arid and semiarid regions. This study was carried out to determine the effect of parent materials on the origin of soil formation and evolution of studied soils. Four different locations in the North East of Marand region were selected for excavation and description of soil profiles. Then, soil samples were taken and soil physicochemical and mineralogical properties were determined for representative profiles and their related parent rocks. X-ray diffraction (XRD) patterns revealed that the soils were similar in claymineral compositions, consisting of illite, smectite, chlorite, kaolinite, and quartz for the different profiles, but vary in the relative amounts of these minerals. Also, XRD analysis of powder refers mainly to the presence of calcite and feldspar with aforementioned clay minerals. Clay mineralogy showed that smectite, illite, chlorite, kaolinite and mica (except 2Bk horizon sample of profile 4) were present in all the soils studied and seem to be inherited from parent materials by weathering processes. Also, a little amount of smectite in profile 1 (B sample) has pedogenic origin. Briefly, mineralogical characteristics showed that soil formation was mainly lithologic origin than pedogenic.