STABLE ISOTOPIC EVIDENCE FROM PALEOSOL CARBONATES AND FOSSIL TEETH INGREECE FOR FOREST OR WOODLANDS OVER THE PAST 11 MA

Mio-Pliocene fluvial rocks containing buried paleosols are common in G reece and Turkey. We used the carbon and oxygen isotopic composition o f 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 A thens, and Rhodes all show that Mio-Pliocene vegetation was dominated by C3 plants, as the entire region is today. In addition, nearly all p aleosols contained carbonate, indicating that mean annual precipitatio n has remained under about lm/yr during the last 11 Ma. The carbon iso topic evidence thus precludes the presence of Serengeti-type C4 grassl ands favored by summer precipitation, but permits C3 forest or grasses fed by winter rains, or forest with mixed seasonal precipitation. How ever, there is no evidence in the published palynological records from the region for abundant grasses. Given these lines of evidence, we su ggest that dry forest and woodland (largely C3) dominated the vegetati on of the region. C3 grasslands, if present, were probably of very res tricted extent. This reconstruction is supported by carbon isotopic ev idence from fossil teeth from Samos and from Pasalar in NW Turkey, and by published evidence on masticatory morphology of Turolian-age rumin ants from Samos and Pikermi. Our findings imply that the classic fossi l-bearing localities on Samos and at Pikermi, and from the lower Axios Valley in Macedonia were not open savannas, as has been previously su ggested, but rather, woodlands or forests.