STRONTIUM ISOTOPIC INVESTIGATION OF HORSE PASTORALISM AT ENEOLITHIC BOTAI SETTLEMENTS IN NORTHERN KAZAKHSTAN

The Copper Age (4^th millennium BC) Botai people of the Eurasian Steppe region in northern Kazakhstan are notable for their numerous stable villages and an economy that depended heavily on the horse.  Faunal remains are overwhelmingly dominated by horse bones, and no evidence exists that domestic crops were raised.  Questions remain as to the origin and sedentary or nomadic nature of the early Botai, and the location and age of the earliest horse domestication.  As one part of a major interdisciplinary investigation, we are carrying out geochemical and strontium (Sr) isotopic analyses of modern and archeological samples from five Botai pit-house settlements (Botai, Krasnyi Yar, Petrovka, Roshchinkskoe, and Vasilkovka) to (1) characterize the geochemical signatures of equine food and water sources at these sites, and at regions further south where horses might have lived seasonally; (2) to compare this to the seasonal (summer vs. winter, based on oxygen isotopic analysis) signature preserved in modern horse enamel; and (3) to extend these results to archeological horse enamel.   

Numerous studies indicate the difficulty of preserving the original isotopic signature of archeological horse teeth.  Most agree that enamel is the material most resistant to post-depositional alteration, and for Sr isotopes, a rigorous sequential leaching procedure for tooth material is necessary.  Based on experiments on several modern and archeological teeth, we have developed a method that we believe extracts unaltered strontium.  Preliminary results indicate that river waters and plants surrounding the Botai sites range from 0.709 to 0.712, but that water and plants from even the same site can vary by as much as 0.003.  Near the Krasnyi Yar settlement, the Chaglinka River has an ⁸⁷Sr/⁸⁶Sr ratio of 0.7124; plant material was 0.7103, and a modern horse tooth showed seasonal differences (winter = 0.7104; summer = 0.7107).  Near Roshchinskoe, the Zhanantuz River has an ⁸⁷Sr/⁸⁶Sr ratio of 0.7101; the plant and a modern tooth sample (winter) were also both 0.7101±0.0001.  These results suggest that Sr isotopes will be capable, in some cases, of tracking seasonal and longer-term horse migration in the Botai region.