Early miocene climate of Central Eurasia - Evidence from Aquitanian floras of Kazakhstan

The rich fossil record in Kazakhstan documents that during the Oligocene and Early Miocene this area in Central Eurasia was densely forested with warm-temperate deciduous trees and shrubs of the so-called "Turgayan flora". Twenty-nine fossil floras (leaf and pollen assemblages) have been selected for a quantitative analysis of the Aquitanian (early Early Miocene) climate in Kazakhstan. Mean annual temperatures are estimated to have been around 15 degrees C, while values of mean annual precipitation are about 1000 nim. In combination with several other climate parameters estimated (temperatures of the warmest and coldest months, precipitation of the wettest, driest and warmest months), these data reflect uniform climatic conditions over several thousands of square kilometres. Temperature parameter estimates show slight spatial differentiation, with generally cooler mean annual temperatures and higher seasonality (i.e. warmer summers and colder winters) in the north-eastern part of the study area compared with the southwestern area around Lake Aral. As compared with palaeoclimate estimates for the European and East Asian Aquitanian, the central part of the Eurasian continent reveals higher seasonality and slightly increased continentality. (C) 2006 Elsevier B.V. All rights reserved.