Large-magnitude (VEI ≥ 7) ‘wet’ explosive silicic eruption preserved a Lower Miocene habitat at the Ipolytarnóc Fossil Site, North Hungary

Abstract

During Earth’s history, geosphere-biosphere interactions were often determined by momentary, catastrophic changes such as large explosive volcanic eruptions. The Miocene ignimbrite flare-up in the Pannonian Basin, which is located along a complex convergent plate boundary between Europe and Africa, provides a superb example of this interaction. In North Hungary, the famous Ipolytarnóc Fossil Site, often referred to as “ancient Pompeii”, records a snapshot of rich Early Miocene life buried under thick ignimbrite cover. Here, we use a multi-technique approach to constrain the successive phases of a catastrophic silicic eruption (VEI ≥ 7) dated at 17.2 Ma. An event-scale reconstruction shows that the initial PDC phase was phreatomagmatic, affecting ≥ 1500 km2 and causing the destruction of an interfingering terrestrial–intertidal environment at Ipolytarnóc. This was followed by pumice fall, and finally the emplacement of up to 40 m-thick ignimbrite that completely buried the site. However, unlike the seemingly similar AD 79 Vesuvius eruption that buried Pompeii by hot pyroclastic density currents, the presence of fallen but uncharred tree trunks, branches, and intact leaves in the basal pyroclastic deposits at Ipolytarnóc as well as rock paleomagnetic properties indicate a low-temperature pyroclastic event, that superbly preserved the coastal habitat, including unique fossil tracks.

The relationship between ignimbrite lithofacies and topography in a foothill setting formed on Miocene pyroclastics – a case study from the Bükkalja, Northern Hungary

“…The boundary between the 3 rd and the 4 th sample area is the widest stream valley in the Bükkalja, the Eger Valley. Here, the Bogács ignimbrite is not observed, and the LPC and UPC (Upper Pyroclastic Complex sensu Szakács, A. et al 1998; see Figure 2) are not clearly separated (Lukács, R. et al 2022;Karátson, D. et al 2022). The 4 th sample area is also distinct with respect to the Bouguer anomaly, because it shows a slight positive anomaly like the 2 nd sample area.…”

“…et al 2005). The Paleogene-Lower Miocene sedimentary deposits is in turn overlain by a several 100 m-thick pyroclastic succession emplaced between ~18.2-14.3 Ma from dozens of large explosive eruptions of dominantly high-K rhyolitic magmas (Figure 2, Szakács, A. et al 1998;Lukács, R. et al 2018Lukács, R. et al , 2022Karátson, D. et al 2022). The current surface occurrence of the pyroclastic succession is confined to a ~10 x 40 km region with NE-SW elongation.…”

“…et al 1995;Szakács, A . et al 1998;Lukács, R. et al 2007Lukács, R. et al , 2015Lukács, R. et al , 2018Lukács, R. et al , 2022Biró, T. et al 2020;Hencz, M. et al 2021a, b;Karátson, D. et al 2022).…”

Insights into the palaeoenvironments, structure and stratigraphy of the lower Miocene of the Eastern Carpathians Bend Zone, Romania

“…The pyroclastic suite at Ipolytarnóc (North Hun gary), ~75 km away from the prox i mal BVF de posit, also has a sim i lar zir con U-Pb and 40 Ar/ 39 Ar age and zir con trace el e ment com posi tion to the Eger ignimbrite as shown by Lukács et al (2021), Šarinová et al (2021) and Karátson et al (2022). Brlek et al (2023) iden ti fied the Eger erup tion-re lated ignimbrite in the Mt.…”

“…Lukács et al (2018) iden ti fied four main early Mio cene ignimbrite-form ing explo sive erup tions in the Bükkalja Vol ca nic Field, north ern Hungary; these are the Csv-2 ignimbrite at 18.2 ±0.3 Ma, the Eger ignimbrite at 17.5 ±0.3 Ma, the Mangó ignimbrite at 17.065 ±0.014 Ma and the Bogács ignimbrite at 16.816 ±0.059 Ma. Recently, Karátson et al (2022) and Brlek et al (2023) re fined the age of the Eger erup tion event to 17.3 Ma and the Csv-2 (named as Wind/Kalnik) erup tion to 18.1 Ma with <100 ky uncer tain ties. The thick Bãtrâni Tuff from the ECBZ rep re sents the prod uct of one such erup tion, which pro vides in di ca tion of a pos si ble large ex plo sive vol ca nic event.…”