Effect of weathering and mineralogy on the distribution of major and trace elements (Hormozgan province, Southern Iran)

Geochemistry composition and mineralogy distribution of different bulk soil and rock samples from Hormozgan province 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 soil characteristics. For this reason, major elements (Si, Al, Fe, Mn, Mg, Ca, Na, K, Ti, and Zr) as metal oxides and mineralogy composition of bulk soil and rocks were analyzed. Total content of some trace elements (Cr, Ni, Cu, Zn, Cd, Sn, and Pb) were measured in bulk soil samples as well. The studied area is part of arid region in southern Iran with predominant sedimentary rocks and evaporiteevaporate formations. Coefficients between the elements of each subgroup are positive and significant (p < 0.05), indicating that their presence can be accounted for by similar reasons. 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. Calcium correlated positively with loss on ignition (LOI) and negatively with Major elements; it does not indicate the anthropogenic origin of Ca. In general, soils developed on metamorphic and igeneous parent rocks rather than evaporates indicated distinct accumulation of Si, Al, Fe, Mn, K, Ti, and Zr in different particles. Indices based on soil macro elements, such as CIA, CIW, PWI, 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 of alkali and alkali earth elements of the sand and silt rich soils, both the Chemical Index of Alteration values (4.61 to 67.40), Chemical Index of 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.