Study on the strontium isotope standard in pig teeth excavated from Zaoshugounao site, Shaanxi Province of China

In archaeology, strontium isotope analysis is developing into an efficient scientific technique for tracing the movement of prehistoric humans and animals. Determining the local bioavailable Sr-87/Sr-86 ratio range is the key to distinguishing whether the human or animal is indigenous to the local area. It has been shown that the Sr-87/Sr-86 ratio in the enamel of pigs can be an excellent sample to determine the range of local strontium isotope ratio at the site. However, pigs may not be all local at the site, and there is no special study on whether pigs' different ages and tooth types impact the local strontium isotope characteristics. In this paper, the tooth enamel of 19 pigs from the Zaoshugounao site for strontium isotope ratio (Sr-87/Sr-86) by multicollector-inductively coupled plasma mass spectrometry. There were no significant differences in Sr-87/Sr-86 ratios of local pigs at different months and different molar types, which did not affect the determination of the local strontium isotope standard. Based on the local strontium isotope ratio range (0.711056-0.711476), we found that five pigs were non-local. The Jing and Wei river basins (in Guanzhong basin) and northern Shaanxi are likely sources of non-pigs.