A series of pottery samples from the Iranian site Tol-e Kamin, ranging from pre-historical period to the New Elamite, were analyzed in order to study the geochemical variability of the pottery assemblage. A total amount of 168 measurements were obtained using a portable XRF device and were statistically handled. The results could successfully distinguish the geochemical composition of potteries from the chalcolithic to the New Elamite periods in the Kur River Basin. A major shift in the use of different clay sources could be detected since the Proto Elamite period and afterward, in which the carbonated and marl content clays represented by Ca, Ba and Sr shifted to clay sources with a tendency to non-carbonate silty clay Al, Ti, and Fe from a different geological background. The results stress the importance of further provenance studies to address issues of trade and exchange possibilities in southwestern Iran.