Stable isotopic evidence from paleosol carbonates and fossil teeth in Greece for forest or woodlands over the past 11 Ma

Mio-Pliocene fluvial rocks containing buried paleosols are common in Greece and Turkey. We used the carbon and oxygen isotopic composition of pedogenic carbonates associated with these paleosols to estimate the proportion of C₃ (trees, shrubs, and cool growing season grasses) and C₄ (warm growing season grasses) plants once present on the landscape. Evidence from the paleosols in well-known fossil-bearing formations in the lower Axios Valley in Macedonia, and from Samos, Pikermi near Athens, and Rhodes all show that Mio-Pliocene vegetation was dominated by C₃ plants, as the entire region is today. In addition, nearly all paleosols contained carbonate, indicating that mean annual pitation has remained under about 1 m/yr during the last 11 Ma. The carbon isotopic evidence thus precludes the presence of Serengeti-type C₄ grasslands favored by summer precipitation, but permits C₃ forest or grasses fed by winter rains, or forest with mixed seasonal precipitation. However, there is no evidence in the published palynological records from the region for abundant grasses. Given these lines of evidence, we suggest that dry forest and woodland (largely C₃) dominated the vegetation of the region. C₃ grasslands, if present, were probably of very restricted extent. This reconstruction is supported by carbon isotopic evidence from fossil teeth from Samos and from Paşalar in NW Turkey, and by published evidence on masticatory morphology of Turolian-age ruminants from Samos and Pikermi. Our findings imply that the classic fossil-bearing localities on Samos and at Pikermi, and from the lower Axios Valley in Macedonia were not open savannas, as has been previously suggested, but rather, woodlands or forests.