Abstract

The NE Tokaj Mountains at Pálháza in NE Hungary are made up of a complex association of Miocene rhyolitic shallow intrusions, cryptodomes and endogenous lava domes emplaced into and onto soft, wet pelitic sediment in a shallow submarine environment. The intrusive–extrusive complex shows a range of interaction textures with the host muddy sediment, ranging from blocky peperites, formed on a 0.1 m-scale, through to irregular contacts closely resembling globular mega-peperites, on a >10 m-scale. The over 200 m-thick igneous succession is interpreted to result from the pulsatory growth of shallow cryptodomes through muddy saturated host sediment. The intrusions eventually breached the sedimentary cover to build up thick in situ hyaloclastite piles in the shallow subaqueous environment. The coherent rhyolitic cryptodome facies is surrounded by intrusive hyaloclastite in the contact zone to the pelitic host sediment. In the upper level of the complex, rhyolitic dome rock is capped and surrounded by hyaloclastite formed due to quench fragmentation upon contact of the lava surface with sea water.