Palaeoclimatic evolution in the Miocene from the Transylvanian Depression reflected in the fossil record

Abstract

AbstractThe palaeoclimate during the Miocene of the Transylvanian Depression (Romania) is interpreted mainly by the response of calcareous nannoplankton, microfauna (foraminifera), molluscs and mammals (rhinoceros) assemblages.The first significant palaeoclimatic event is recorded during the early Miocene. The climatic warming at the level of the Vima Formation was followed by a more important warming during the Eggenburgian, which is preserved in the fossil record of the Corus Formation. During the Ottnangian, a cooling episode is recorded in the Hida Formation, probably related to Atlantic and Boreal influences. The climate on land was probably subtropical, humid, but much cooler than the Eggenburgian, as the remains of rhinoceros from this formation indicate.The Middle Miocene marine sub-tropical assemblages are present in the Dej Formation (early Badenian), but towards its upper part sub-tropical species become scarce. The endemic elements, with boreal influences, are recognized in Kossovian strata. On land, the Moravian rhinoceros also suggest a sub-tropical climate, with marshy, densely afforested areas. Another rhinoceros found in the upper part of the Moravian, indicates a tendency to the continentalization of the climate. The early Sarmatian began with short period of warming, followed again by a cooling episode (Feleac Formation).The last significant warming is recorded in the Late Miocene, during the Pannonian (Lopadea Formation). The small aceratheres from the Pannonian suggest marshy areas with a relatively warm climate.