Geochemical analysis of multi-element in archaeological soils from Tappe Rivi in Northeast Iran

Multi-element analysis in historical sites is a major issue in archaeological studies; however, this approach is almost unknown among Iranian scholars. Geochemical multi-element analysis of soil is very important to evaluate anthropogenic activities. The aim of this study consists of assessing the potential usefulness of multi-elemental soil analysis, obtained by Analytical Jena atomic absorption spectrophotometer (AAS) and ICP-MS, to recognize ancient anthropogenic features on the territory of Tappe Rivi (North Khorasan, Iran). For that purpose, a total of 80 ancient soil samples were sampled from each soil horizon and cultural layer. The research involved Fe, Al, Cd, Cu, Ni, Co, Cr, Pb, and P which trace element samples were extracted according to the International Standard ISO 11466 and phosphorus samples by Olsen method. Besides, the contamination of the soils was assessed based on enrichment factors (EFs) by using Fe as a reference element. This geochemical/archaeological approach highlights that the content of most elements in the Parthian and Sassanid ages were significantly higher than the contents of the elements in other zones, which shows that by the development of the eras, the content of the elements has also increased. Also, the accumulation of metals in the Rivi site was significantly higher than in the control area. Among the sampled zones, enrichment factor (EF) indicated that the enrichment of Cu and phosphate at the Parthian and Sassanid had the highest content. This result is important because it shows that the amount of metals and human activities are directly related to each other during different ages.