2026-06-30T02:12:22Zhttps://riubu.ubu.es/oai/request

oai:riubu.ubu.es:10259/60962022-11-29T09:16:42Zcom_10259.4_2560com_10259_5086com_10259_2604col_10259.4_2561

Biró, Tamás Hencz, Mátyás Németh, Károly Karátson, Dávid Márton, Emő Szakács, Alexandru Bradák, Balázs Szalai, Zoltán Pécskay, Zoltán Kovács, István János 2021-11-04T11:29:13Z 2021-11-04T11:29:13Z 2020-09 0377-0273 http://hdl.handle.net/10259/6096 10.1016/j.jvolgeores.2020.106973 A Middle Miocene, ~8 m thick pyroclastic succession, reported from the Bükk Foreland Volcanic Area (BFVA) in Northern Hungary (Central Europe) specified here as the Jató Member, was produced by silicic phreatomagmatism (Phreatoplinian sensu lato). Two well-preserved outcrops ~8 km apart and inferred to be within ~10–50 km from source represent the discontinuously exposed, layered, paleosol-bounded, phreatomagmatic JatóMember. They show an identical phenocrystal assemblage of feldspar, biotite and amphibole without weathered zones or signs of erosion, that suggest deposition in one eruption phase lasting hours to months. The succession contains three subunits: 1) subunit A, 1.8 m thick, a series of well-sorted fine to coarse ash or lapilli tuff layers with constant thickness; 2) subunit B, 2.1 m thick, a series of normal-graded layers with an upper fine-grained zone containing abundant ash aggregates with a coarser-grained core and distinctively finer-grained outer rim; 3) subunit C, 4.5 m thick, a massive, poorly to well-sorted coarse ash with gas escape structures and ash aggregates at its base. The upward change of these lithofacies implies an initially sustained dry fallout-dominated deposition of ash and pumice lapilli resulting in subunit A. Subsequently, multiple wet and dilute Pyroclastic Density Currents (PDCs) dispersed subunits B and C. The general abundance of PDC-related ash aggregates in the middle-upper part of the succession (particularly in subunit B), and the transformation of a fall-dominated to a collapsing depositional regime producing wet dilute PDCs, imply the increasing influence of water during the eruption (Phreatoplinian sensu lato). The presence of water is related to an epicontinental sea duringMiddle to LateMiocene in the Carpatho-Pannonian region. The transition from an initial dry magmatic phase generated fallout activity followed by the emplacement of wet PDCs' rich in ash aggregates, when external water infiltrated from a surrounding lake or sea water entered the vent. eng http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess Attribution-NonCommercial-NoDerivatives 4.0 Internacional Silicic hydrovolcanism Accretionary lapilli Dry-to-wet transition Miocene Bükk Foreland Volcanic Area Carpatho-Pannonian region A Miocene Phreatoplinian eruption in the North-Eastern Pannonian Basin, Hungary: The Jató Member info:eu-repo/semantics/article