Lithofacies associations of the first-stage volcanic activity of the Miocene Börzsöny Mountains, North Hungary, have been reconstructed in the light of detailed volcanological mapping, volcanic glass geochemistry and evaluation of palaeogeographic data. In the deeply eroded hilly area, near-vent primary and distal/reworked ring-plain volcaniclastics, preserved in a mosaical pattern, have been identified. Facies distribution reveals two probable facies continua: (a) A shallow-marine silicic explosive to resedimented volcaniclastic; and (b) A subaerial debris-flow to fluvial-and shallow-marine debris-flow/turbidite association. Facies characteristics and distribution allow us to (a) substantiate small-sized calderas, the eroded rims or proximal palaeoslopes of which have been preserved by volcaniclastic breccias (mostly debris-flow deposits); (b) reconstruct a well-developed volcaniclastic apron, spread mostly to the north and representing a south-to-north transport direction. Palaeogeographic interpretation of facies successions indicates a shallow-water initial explosive stage and a subsequent, rapidly evolving, emergent ring plain stage fed by different types of volcaniclastic debris flows.
- Debris flow
- Explosive volcanism
- Subaqueous pyroclastic flow
- Volcanic lithofacies associations
- Volcaniclastic apron
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)