El Paso Museum of History

Abstract Voluminous Miocene silicic volcanism sourced mainly from the extensional Pannonian Basin played a major role in the evolution of Central Paratethys. Here, we identify a widely distributed (> 3150 km 2 ) member of the Upper Rhyolite Tuff, 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) and distinctive glass geochemistry. Its calculated minimum volume (~ 200 km3) implies a VEI ≥ 7 eruption. The ignimbrite 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 Hungary—, while the strongly phreatomagmatic character and free-floating foraminifer content in the ignimbrite suggest a marine environment at the source vent. These finds show a rapid environmental change from a long Mid-Miocene terrestrial period in the northern Pannonian Basin to a late Badenian marine incursion.