Application of Strontium Isotope Analysis of Bone and Tooth in the Study of Ancient Immigrations

One of the important questions of archaeology is the study of the mobility and immigration of human groups. A common method for addressing these issues is to refer to the artifacts and archaeological findings left behind by the earlier cultures and to compare the forms, motifs, and production methods used among various ancient cultures, and hence, to explore the relationships and cultural exchanges between the societies. But, in the last three decades, the analysis of strontium isotopes in human tooth and bone samples (and even animals) has made it possible to study ancient immigration using a new method. According to the results of scientific researches, 87Sr/86Sr in each region is different due to the geological complications and the genus and stony sediments with 87Sr/86Sr of other regions. By measuring 87Sr/86Sr in bone and skeletal samples and comparing it with the average 87Sr/86Sr geological ratio in the region, the samples of the studied skeletons can be either indigenous or migratory. Since the people of the Piranshahr area in Iran have still traffic to the cities of Erbil and Sulaimaniyah in Iraq, and according to the studies, most villagers from Silveh village migrated to this region during the past century from the Iraqi Kurdistan, the immigration study of skeletons found in Tepe Silveh archaeological site could be interesting. The purpose of this study was to use the analysis of stable isotopes of strontium of the teeth and bone samples of skeletons obtained from the archaeological site of Tepe Silveh, Piranshahr, in order to determine their native or migratory nature. Tepe Silveh or as villager named “Tepe Sheikh Esmail Silveh” (N: 36° 48chr('39') 099chr('39')chr('39') – E: 45° 05chr('39') 937chr('39')chr('39') – altitude: 1567 m) is located exactly 100 m north of the Silveh village. Tepe Silveh is located in the center of intermountain river valley on the northern margin of the village, which has already been demolished and abandoned. As explained above, the reason for the destruction of the village was the sinking in the basin of the Silveh Dam. Seven Excavation trenches in Tepe Silveh have revealed, important materials from Early Chalcolithic Dalma (5000 BC) culture, Late Chalcolithic, Early Bronze Age culture of Hasan Ali or Nineveh V (3500- 2700 BC), Iron Age and Parthian periods. After a gap, Tepe Silveh have re-settled during Millde Islamic Periods (Seljuk era) and continued up to the late Islamic Period. According to the important location of Tepe Silveh and different occupation of the site deformation from Early Chalcolithic Dalma period to Islamic era, it should be suggested as a particularly important case study of migration, because it has been active and dynamic during different periods. Proximity of the site to the Iran, Iraq and Turkey adds to the importance of this study. To achieve this, the 87Sr/86Sr of the samples was measured. By comparing the ratio of strontium isotopes, it was possible to determine whether the samples were indigenous or migratory. The results obtained showed the different proportions in the analysis of strontium isotope, so that all samples could be considered non-native. Of course, this comment is only expressed on the basis of these five skeletons, and more specimens and analysis are needed to comment on the archaeological site of Piranshahr.