Late Miocene climatic and environmental variations in northern Greece inferred from stable isotope compositions (δ18O, δ13C) of equid teeth apatite

Abstract

During the late Miocene Vallesian–Turolian transition, an important faunal turnover affected continental vertebrate faunas, and particularly primates with the replacement of hominids by cercopithecid monkeys in Europe. In order to better understand this turnover from a climatic perspective, stable oxygen and carbon isotope compositions of fossil equid tooth enamel contemporaneous with either hominids or cercopithecids have been analyzed. Hipparion teeth recovered from seven Greek localities spanning from the late Vallesian to the end of Turolian have δ18Op values of apatite phosphate suggesting an increase in mean air temperatures from 13±3°C at the beginning of the Vallesian to 17±2°C during the late Turolian. δ13C values of local plants have been estimated using the carbon isotope compositions of apatite carbonate. By applying to our data the relationship established between the δ13C value of modern C3 plants and mean annual precipitations, estimated average precipitations slightly decreased from 890 (+109−100) mma−1 to 471 (+58−54) mma−1 during this time span. According to Köppen's classification of climates, northern Greece was submitted to modern-like Mediterranean climates during the late Miocene. The change in climatic conditions, which took place during the late Vallesian–early Turolian transition, remained within the range of Mediterranean climate modes, thus being unlikely at the origin of a dramatic modification in local vegetation. This study strongly suggests that climate might not be the key factor of the Vallesian–Turolian major faunal turnover at least in the Eastern Mediterranean Basin.