A volcanic catastrophe destroyed the environment of ancient Ipolytarnóc 20 million years ago. The grey volcanic rock, rhyolite tuff, which demolished the paleohabitat, appears on the surface on both sides of the geological trail towards the Great Hall. It contains the charred remnants of the ancient vegetation.
The volcanism started with ashfall deposition, blanketing the habitat with fine, yellowish-striped volcanic dust.
Then a firey deluge of ashflow, ignimbrite came, like an avalanche, burning and burying everything on its way.
The base surge's accreted lapilli, tuffballs are easy to identify along the geological path. According to radiometric dating, measurements, the volcanic catastrophe destroyed the paleo- habitat of Ipolytarnoc 19.6 million years ago, although recent studies debate this date.