Bondoró Volcanic Complex (shortly Bondoró) is one of the most complex eruption centre
of Bakony-Balaton Highland Volcanic Field, which made up from basaltic pyroclastics
sequences, a capping confined lava field (~4 km 2) and an additional scoria cone.
Here we document and describe the main evolutional phases of the Bondoró on the basis
of facies analysis, drill core descriptions and geomorphic studies and provide a general
model for this complex monogenetic volcano. Based on the distinguished 13 individual
volcanic facies, we infer that the eruption history of Bondoró contained several stages
including initial phreatomagmatic eruptions, Strombolian-type scoria cones forming
as well as effusive phases. The existing and newly obtained K-Ar radiometric data
have confirmed that the entire formation of the Bondoró volcano finished at about
2.3 Ma ago, and the time of its onset cannot be older than 3.8 Ma. Still K-Ar ages
on neighbouring formations (e.g. Kab-hegy, Agár-teto) do not exclude a long-lasting
eruptive period with multiple eruptions and potential rejuvenation of volcanic activity
in the same place indicating stable melt production beneath this location. The prolonged
volcanic activity and the complex volcanic facies architecture of Bondoró suggest
that this volcano is a polycyclic volcano, composed of at least two monogenetic volcanoes
formed more or less in the same place, each erupted through distinct, but short lived
eruption episodes. The total estimated eruption volume, the volcanic facies characteristics
and geomorphology also suggests that Bondoró is rather a small-volume polycyclic basaltic
volcano than a polygenetic one and can be interpreted as a nested monogenetic volcanic
complex with multiple eruption episodes. It seems that Bondoró is rather a "rule"
than an "exception" in regard of its polycyclic nature not only among the volcanoes
of the Bakony-Balaton Highland Volcanic Field but also in the Neogene basaltic volcanoes
of the Pannonian Basin.