Progressive substitution of a subtropical forest for a temperate one during the middle Miocene climate cooling in Central Europe according to palynological data from cores Tengelic-2 and Hidas-53 (Pannonian Basin, Hungary)

International audience; The palynological analysis in the Karpatian–Sarmatian (late Early-Middle Miocene) interval of the cores Tengelic-2 and Hidas- 53 (Hungary) reveals the existence of a forest organized in altitudinal belts, developed in a subtropical–warm temperate humid climate, reflecting the so-called Miocene climatic optimum. Pollen changes from the late early Miocene to the late middle Miocene have been observed and are related to climatic changes. The vegetation during the Burdigalian and the Langhian was dominated by thermophilous elements such as evergreen trees and Engelhardia, typical of a present day rain and evergreen forest at low altitudes (i.e. SE China). During the Serravallian several thermophilous elements strongly decreased, and some of them disappeared from the central European area. Thus, the rain and evergreen–deciduous mixed forest suffered a great transformation due to the loss and decrease in the abundance of several evergreen plants. This kind of vegetation was progressively substituted by deciduous and mesothermic plants such as deciduous Quercus, and Fagus, Alnus, Acer, Carpinus, Ulmus, Zelkova, etc. At the same time, the presence of altitude coniferous trees increased. This climatic cooling is correlated with global and regional climatic changes.