Hakime Abbaslou - Department of Civil Engineering Sirjan University of Technology Sirjan, Iran

The influence of geologic factors and soil-forming processes on the distribution of elements vary strongly among elements and soil profiles. Mineralogy distribution and geochemistrycomposion of some arid soil and rock samples from southern Iran were investigated in order to address element distribution of soils in the context of their weathering, soil forming process and geology to describe impacts of parent material and soil evolution on the soilcharacteristics. For this reason, major elements (Si, Al, Fe, Mn, Mg, Ca, Na, K, Ti, and Zr) as metal oxides and mineralogy compositionof bulk soil and rocks were analyzed. Most samples and most elements controlled by the geochemical composition of parent material, this may be attributed to the weak soil development and lack of soil contamination in the studied pedons. Silicon, Mn, Ti, and Zr contents are mainly controlled by a lithogenic factor, while Al, Na, K, Ca, Mg, Ni, Zn, P attributed to pedogenic controls rather than lithogenic factor whereas Na attributed partly to anthropogenicfactors. In general, soils developed on metamorphic and igeneous parent rocks rather than evaporates indicated distinct accumulation ofSi, Al, Fe, Mn, K, Ti, and Zr in different particles. Indices based on soil macro elements, such as Chemical Index of Alteration values(CIA), Chemical Index of Weathering (CIW), Product of Weathering Index (PWI), Weathering Index of Parker (WIP) could express the variations in unweathered materials and rate of weathering and can be taken as an index of soil development. In addition to high contents ofalkali and alkali earth elements of the sand and silt rich soils, both the Chemical Index of Alteration values (4.61 to 67.40), Chemical Indexof Weathering values (4.82 to 71.73) and also high Product of Weathering Index (PWI) and Weathering Index of Parker (WIP) contents, suggests a relatively mild weathering source area.

Soil geochemistry; pedogenesis; arid climate