## 3 Results and Discussion
### Isotopic Analysis in Modern Mammals
#### 3.2.2 \(\delta^{34}\)S Values of Various Mammals  
The \(\delta^{34}\)S values of various herbivores range between 4.0% and 9.7%. Taking into account that the isotope fractionation between the dietary sulfate and the bone collagen averages 1% [21; 34; 35], the difference in \(\delta^{34}\)S values observed between the diet and the mammals' collagen (more than 5%) indicates that these mammals obtained their food from different geographical areas (Table 5). However, the animals (cattle) from the same area (Chalkidiki peninsula) demonstrate a difference in sulfur isotopes greater than 1%, which is probably due to sulfide ore deposits. Herbivores primarily feed on grass, which constitutes the bulk of their diet. Fresh grass absorbs sulfur from the soil and atmosphere during growth. This sulfur can originate from natural sources or anthropogenic sources. Therefore, herbivores from the same area should present the same sulfur isotope, although herbivores from the entire Greek region should provide an sd > 2%, especially because of the complex geology of Greece. Similarly to sulfur isotopic values in plants, the \(\delta^{34}\)S values in mammals demonstrate regional soil differences that can influence sulfur isotopes, which were not recorded in isotopic data. Sulfur isotopic values in Greek herbivorous mammals reflect a homogenous sulfur isotope dataset that could not be related to soil sulfur. In particular, animals (cattle, free-range) from the same area (Chalkidiki), present a difference in sulfur isotopes greater than 1% (sd = 1.8%), which is probably due to different soil elements. Figure 8: \(\delta^{15}\)N versus \(\delta^{13}\)C of the studied plants and mammals from different localities in Greece. The local flora from the Chalkidiki peninsula can take up sulfur from atmospheric reservoirs, freshwater (\(\delta^{34}\)S values range between 21.4 and 10.1% (82)), thermal water (\(\delta^{34}\)S values range between 12.6 and 13.8%) (78) and mainly sulfide minerals. It is well known that the Chalkidiki peninsula hosts enormous massive sulfide ore deposits and, thus, is a metalliferous area (e.g., (83; 84; 85)). The pyrite presents \(\delta^{34}\)S values ranging from \(-1\) to 3%. Therefore, the \(\delta^{34}\)S value of sulfur in Chalkidiki could range from \(-1\) to \(+21.4\)%. Considering the fractionation factors, plants are depleted in \(\delta^{34}\)S by \(-1\) to \(-2\)% relative to their S source, and vegetation in Chalkidiki could show \(\delta^{34}\)S values between \(-3\) and \(+20\)%. In addition, considering that mammals are not fractionated in their diet (35,86), domestic animals raised in Chalkidiki that consume local vegetation could not present \(\delta^{34}\)S values greater than 20%. Mammals from Chalkidiki have a \(\delta^{34}\)S value of less than 20%. So, lower sulfur isotope values probably mean that the animals grazed on vegetation that obtains its sulfur mainly from \(\delta^{34}\)S-depleted minerals. On the other hand, \(\delta^{34}\)S values likely indicate that the animals grazed closer to \(\delta^{34}\)S-enriched geothermal water sources or grazed on coastal vegetation affected by sea spray, as in the present study. Furthermore, a difference between nitrogen and sulfur isotope values was also observed, which may also be explained by different husbandry methods and by climate: animals from the same area [i.e., Chalkidiki, standard deviation (cattle), \(\delta^{34}\)S, 1.8%] present distinct patterns in nitrogen and sulfur isotope ratios. The distribution of mammals from various regions of Greece is reported herein (Figure 9). Regardless of the origin, it has been observed that cattle present lower \(\delta^{34}\)S values compared to those values of lambs. Moreover, mammals (cattle and sheep) from the Chalkidiki peninsula and Crete Island differ in their \(\delta^{15}\)N and \(\delta^{34}\)S values by more than 1% (see Figure 9).