Horváth Tünde - Ruttkay, Elisabeth: Mödling-Jennyberg. A Hilltop Settlement of the Boleráz and Leithaprodersdorf Cultures (Budapest, 2023)
CHAPTER 9. ANIMAL BONE STABLE ISOTOPE STUDIES FROM THE MÖDLING REGION (Sándor Gulyás - Tünde Horváth) - 9.1. Introduction (Sandor Gulyas)
718 ANIMAL BONE STABLE ISOTOPE STUDIES FROM THE MÖDLING REGION extent of herding strategies such as the emergence of transhumant pastoralism (Balasse et al. 2002; Britton et al. 2011; Gerling et al. 2012a, Gerling et al. 2012b, Gerling et al. 2017a, Gerling et al. 2017b; Price et al. 2002; Sishlina et al. 2018; Valenzula et al. 2016). The approach makes use of the fact that the Sr isotopic compositions of geological units, soils, plants, and the hard tissues of the mammals in the same environment are closely related. The Sr isotopic signatures may be highly characteristic and can vary over relatively short geographic distances (Battaile-Bowen 2012; Bowen 2010; Voerkelius et al. 2010). The local 87Sr/86Sr signature is passed along the food chain and is incorporated into the teeth of animals during enamel mineralization, with negligible fractionation. Due to the mechanism of Sr absorption in the stomach, plants are the dominant source of Sr for herbivores and omnivores (Price et al. 1985, Price et al. 2002). Provided that the 87Sr/86Sr values in the environment are indeed sufficiently different, enamel Sr isotope measurements may allow the identification of potential pasture areas at and nearby former settlements, and of cattle mobility across geological units (Capo et al. 1998; Gerling et al. 2012a, Gerling et al. 2012b, Gerling et al. 2017a, Gerling et al. 2017b; Mauer et al. 2012). An excellent biogeochemical study examining seasonal transhumance in the Swiss Alps has found significant differences in bulk cattle high-crown molar samples, which was interpreted as a sign of seasonal herd migration (Gerling et al. 2012a, Gerling et al. 2012b, Gerling et al. 2017a, Gerling et al. 2017b). There are certain cases when 87Sr/86Sr values in the environment are not sufficiently different due to the large spatial homogeneity of soil or bedrock types. This usually poses problems for the accurate determination of the environmental background value to which the values recorded in the enamel can be compared. In these cases, the introduction of other ecological and mobility tracers can help. One excellent example is the use of 204Pb/206Pb, 206Pb/208Pb, 204Pb/208Pb isotope ratios (Gulson et al. 1997; Kam ENov 2008). In contrast to Sr, lead enters the body through direct ingestion or inhalation, and it often provides more constrained information on mobilities than Sr (Abrahams-Steigmajer 2003; Kamenov 2008). The data add support to the suggestion that 034S can also be used as a mobility indicator (e.g, Hemer et al. 2016), while Rb/Sr ratio can be used as an erosion indicator (Dietre et al. 2019). Pb isotope analysis is commonly used in geologic studies (e.g. Crocetti et al. 1988; Goldhaber et al. 1995; Pótra et al. 2018) and provides a multivariate isotopic dataset that (when combined with other elements like Sr) has the potential to be more sensitive to regional differences than Sr alone. Nonetheless, unlike the biologically available Sr method (Beard-Johnson 2000; Bentley 2006; Price et al. 2002), a method to use Pb isotopes for assessing ancient geographic origins has yet to be formally defined and demonstrated (Grupe et al. 2017; Samuelsen-Potra 2020). The isotopic ratios of Sr and Pb recorded in the enamel are often used in combination with light stable isotope analyses (613C, 615N, 618O, 634S). Carbon, oxygen, nitrogen, and sulphur isotopic variations in archaeological tooth enamel have been used to investigate prehistoric herd management in several studies (Ambrose-Norr 1993; Battaile et al. 2021; Ebert et al. 2021; France 1996; Heaton 1987; Hemer et al. 2017; Kelly 2000; Kohn 2010; Marshall-Zhang 1993; Tieszen 1991; van der Merwe-Medina 1989, van der Merwe-Medina 1991). However, using such an approach requires that the study area offer a significant variability of carbon, sulphur, and oxygen isotopic compositions, i.e., different vegetation formations involving carbon isotopic variations, and different water sources leading to oxygen isotopic variations, different sourcing our sulphur to the area. Large dispersion of Ô13C, 034S and 015N in a single tooth or multiple teeth may be linked to a different feeding strategy, with more seasonal changes in the available plant food (Marshall-Zhang 1993; Tieszen 1991; van der Merwe-Medina 1989, van der Merwe-Medina 1991). These changes may be of natural origin, due to seasonal cycles in the local vegetation, or to anthropic influence such as vertical transhumance or foddering (Olsen et al. 2014).