Voluminous Miocene silicic volcanism sourced mainly from the extensional Pannonian
Basin played a major role in the evolution of the Central Paratethys. Here, we identify
a widely distributed (> 3150 km2) member of the Upper Rhyolite Tuff in Hungary, called
the Dobi Ignimbrite, with a precise sanidine/plagioclase 40Ar/39Ar age of 13.064 ±
0.065 Ma (~ Badenian/Sarmatian boundary in Central Paratethys chronology). It has
distinctive glass geochemistry with wide compositional variations, which conforms
with large-scale silicic explosive eruptions. In line with this, the calculated minimum
volume (~ 200 km3) of the Dobi Ignimbrite is consistent with a high-end VEI 7 eruption,
with possible ultradistal transport distance of over 300 km. Most of the pyroclastic
succession, which erupted in two phases, was emplaced on land, as it contains leaves
and tree trunks in the basal layer that we correlate with the Badenian/Sarmatian ‘volcanic
floras’ of northern Hungary. At the same time, the ignimbrite has a strongly phreatomagmatic
character, and, together with the presence of free-floating foraminifera, this suggest
that the source vent was located in coastal waters of the Central Paratethys. These
findings indicate either a late Badenian marine incursion prior to the eruption, or
the shift of the eruption center toward the sea.
