A newly discovered youngermost (13.07 Ma) “Upper Tuff”, a large-volume phreatomagmatic ignimbrite in the Pannonian Basin, drapes the present, faulted/dissected topography

Silicic ignimbrite volcanism played a major role in the Miocene evolution of the Central Paratethys. The most voluminuous ignimbrites identified to date (18.1–14.4 Ma) were emplaced in various paleoenvironments in the North Pannonian Basin, thus they are extremely helpful in regional stratigraphy. Here, we present the discovery of a previously unknown but widespread, youngest member of the “Upper Rhyolite Tuff“, referred to as Dobi Ignimbrite, which shows a distinctive glass geochemistry. High-precision sanidine and plagioclase Ar-Ar dating yielded 13.066±0.019 Ma (earliest Sarmatian stage in Paratethys chronology), significantly shifting the previously claimed termination (i.e. Badenian) of the North Pannonian ignimbrite flare-up. In addition, we demonstrate that, although the Dobi Ignimbrite is underlain by a marine sedimentary succession, it was emplaced on land, as it bears leaves and tree trunk fragments and is rich in charcoal. Despite the highly faulted terrain as well as intense dissection and erosion controlled by the neotectonic evolution of the Pannonian Basin, the observed areal extent (c. 1000 km2) and calculated minimum volume (c. 50 km3) of the ignimbrite may represent a VEI= 6 or 7 eruption, which needs to be further delineated. At the same time, the ignimbrite has a strongly phreatomagmatic character, suggesting an abundant, possibly shallow sea- or residual lake water source that was likely limited to the vent area (e.g. caldera graben). The detected sharp environmental change from submarine to terrestrial, as defined by the timing of ignimbrite emplacement at c. 13 Ma, marks the latest Badenian regressive period, followed by a Sarmatian erosion during the Central Paratethethys evolution.