Towards a new time scale for the Upper Miocene continental series of the Pannonian basin (Central Paratethys)

Abstract

In this study we assert that most of the "Pontian" stratigraphic succession of western Hungary is much older than Pontian stage (older than 7 Ma). In fact, these strata form a clearly distinct chronostratigraphic unit between the Pontian strata (as they are defined in the type area of the Black Sea basin) and the Pannonian strata (as they are de- fined in the type area of the Vienna basin). To denote such a problematic chronostratigraphic interval we propose the in- troduction of a new stage (or substage) named Transdanubian between the Pannonian sensu stricto (s.s.) and Pontian s.s. stages of the Upper Miocene series of the Central Paratethys System (ca. 9.0-7.4 Ma in the chronology adopted in this study). The Transdanubian stage has been defined in terms of biostratigraphy, lithostratigraphy, magnetostratigraphy and allostratigraphy. The location of a suitable stratotype has also been proposed. As a first approach, we tried to avoid the in- troduction of new terms in the already complex chronostrati- graphic nomenclature of the Pannonian basin. However, we arrived to the conclusion that the introduction of the Trans- danubian as a new stage (or substage) is a necessary break- through, to avoid further confusion and circular reasoning in- volving facies associations versus chronostratigraphic units. Transdanubian strata represent a distinct anticipation of the Pontian facies within the intra-Carpathian area. The fact that these strata have been reported for decades as "Pontian" in the literature has been the source of much terminological confusion and chronostratigraphic miscorrelation.