Geochemical Investigation of Davarzan Surface Soils, West of Sabzevar, NE Iran

The geochemical composition of surface soils and potential bedrocks in davarzan area has been investigated to determine soilorigin and evaluate environmental aspects. davarzan plain is composed of soils and deposits derived by weathering andtransportation of different bedrocks from northern mountains. the bedrocks consist of eocene (andesitic to basaltic lavas andvolcano-sedimentary rocks composed of alternating beds of marl, sandstone and tuffaceous lime stone) and ophiolitic (peridotitesand serpentinites) units. davarzan soils have high concentration of mg (22000-28000 ppm), cr (693-1353ppm), co (31-51ppm) andni (486-1105 ppm) and low al (28000-51000 ppm), k (3000-10000 ppm), na (1700-7900 ppm), ce (10-22 ppm), li (9-16 ppm) andzn (19-30 ppm). these characteristics are very similar to composition of serpentinite and peridotite rocks and completely differentfrom other lithologies. it could be inferred that these rocks are the major parental materials for davarzan soils. the strong correlationbetween major and trace elements of soil samples indicates identical geogenic origin for their production. anthropological processesdo not have significant effect on the soil composition so that all samples (include natural, agricultural and residential) show the samegeochemical particulars. the content of ni, cr and co is higher than maximal permissible concentration for environmental issues andcould be regarded as potential risk in related topics.