Oxygen isotope analysis of tooth enamel for reconstructing seasonality of Ovicaprine birth

A new method of oxygen isotope analysis of tooth enamel for determining the birth season of small cattle is proposed. Oxygen from a solid sample of tooth enamel is converted into gaseous CO through interaction of the sample with carbon in helium flow at a temperature of1300°C. This method makes it possible to establish the isotopic composition of oxygen in all components of tooth enamel, including phosphates, which constitute 90 wt.% of tooth enamel resistant to diagenesis. Traditionally, isotope analysis of carbonates in tooth enamel, the content ofwhich is only 4%, has been used for determining the seasonality of birth of small livestock. The proposed method of isotopic analysis does not require multi-stage chemical sample preparation. Mechanical purification and sampling of tooth enamel is sufficient to reveal the minimums and maximums in the dependences “SI8O - distance from the enamel/ root junction.” This method was tested on molars M1 and M2 of two modern Ovicaprine animals from the vicinity of the village of Shak-Shak near the city of Aidarken (Southern Kyrgyzstan). Based on the cyclic variations of SI8O in enamel along the growth line of molars ofmodern Ovicaprine, the birth season of the animals - March-April - was established. For the first time, it has been proposed to use cyclic variations of SI8O along the growth line of the M1 molar for determining the seasonality of birth of small cattle. A new internal standard for oxygen isotope analysis SURCAL - calcite from the Surungur (SI8OVPDB = -8.51 %%) was used in this study.