Modern analogues for Miocene to Pleistocene alkali basaltic phreatomagmatic fields in the Pannonian Basin: “soft-substrate” to “combined” aquifer controlled phreatomagmatism in intraplate volcanic fields Research Article

Abstract

Abstract:The Pannonian Basin (Central Europe) hosts numerous alkali basaltic volcanic fields in an area similar to 200 000 km 2 . These volcanic fields were formed in an approximate time span of 8 million years producing smallvolume volcanoes typically considered to be monogenetic. Polycyclic monogenetic volcanic complexes are also common in each field however. The original morphology of volcanic landforms, especially phreatomagmatic volcanoes, is commonly modified. by erosion, commonly aided by tectonic uplift. The phreatomagmatic volcanoes eroded to the level of their sub-surface architecture expose crater to conduit filling as well as diatreme facies of pyroclastic rock assemblages. Uncertainties due to the strong erosion influenced by tectonic uplifts, fast and broad climatic changes, vegetation cover variations, and rapidly changing fluvio-lacustrine events in the past 8 million years in the Pannonian Basin have created a need to reconstruct and visualise the paleoenvironment into which the monogenetic volcanoes erupted. Here phreatomagmatic volcanic fields of the Miocene to Pleistocene western Hungarian alkali basaltic province have been selected and compared with modern phreatomagmatic fields. It has been concluded that the Auckland Volcanic Field (AVF) in New Zealand could be viewed as a prime modern analogue for the western Hungarian phreatomagmatic fields by sharing similarities in their pyroclastic successions textures such as pyroclast morphology, type, juvenile particle ratio to accidental lithics. Beside the AVF two other, morphologically more modified volcanic fields (Pali Aike, Argentina and Jeju, Korea) show similar features to the western Hungarian examples, highlighting issues such as preservation potential of pyroclastic successions of phreatomagmatic volcanoes.

Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review

“…It seems that much evidence points to the fact that the phreatomagmatic volcanic fields, including their maars, were probably dominated by soft-substrate aquifer controlled, shallow and broad maars with occasional mixed aquifer controlled maars that formed over fracture-controlled aquifers. Another paper in this volume presents some detailed account on the potential analogy for the Pannonian Basin phreatomagmatic volcanoes [79].…”

“…However, many of the relatively small-volume volcanoes in a basaltic volcanic field can exhibit very complex volcanic architectures, and in many cases their eruption history shows signs of multiple and recurring activity over long periods of time [43]. The transition between small-volume but complex basaltic volcanoes and long-lived but relatively small-volume composite volcanoes is rather gradual [22,44]. Among polygenetic volcanoes Francis [32] has distinguished simple cones, composite cones, compound volcanoes and volcano complexes.…”

Hungarian national report on IAVCEI 2007–2010

“…A special volume of the Central European Journal of Geosciences on the physical volcanology of the Carpahian-Balkanian Region (including Carpathian-Pannonian Region was organized by Németh and Pécskay (2010). In this volume Lexa et al (2010) overviewed the main characteristics of the volcanic forms found in the Carpathian-Pannonian Region that is completed a number of case-studies (Németh 2010, Keresztúri et al 2010 highlighting that this area could be a natural laboratory for volcanologists.…”

Shallow-seated controls on the evolution of the Upper Pliocene Kopasz-hegy nested monogenetic volcanic chain in the Western Pannonian Basin (Hungary)

“…A "sensu stricto" monogenetic volcano is defined as: "a volcano that was active for a relatively short period of time, days to years, and that erupted in many small-volume eruptions" (Lorenz 2007;Németh et al 2010). However, a large number of volcanoes traditionally viewed as monogenetic seem to be actually complex volcanic edifices and their eruption histories are defined by multiple eruptive phases or is even polycyclic and/or polymagmatic in nature Kereszturi et al 2010;Needham et al 2011).…”

“…On the other end of the magma fragmentation spectrum is the "wet" explosive interaction of magma with water resulting in phreatomagmatic eruptions that form maars, tuff rings and tuff cones (Lorenz 1973(Lorenz , 1986Wohletz & Sheridan 1983;Lorenz & Kurszlaukis 2007). Maar and tuff ring volcanoes form when the rising magma interacts either with ground or surface water respectively (Lorenz 1986;Németh et al 2010;White & Ross 2011). The evolution of a phreatomagmatic volcano is commonly related to 1) syn-eruptive valley systems where water is readily available below the surface along hydrologically active faults and fractures such as in the West Eifel Volcanic Field in western Germany (Lorenz 1984;Lorenz & Zimanowski 2000), or 2) in low lying, well-drained siliciclastic sedimentary basins such as the Pannonian Basin in Central Europe in which the Bakony-Balaton Highland and Little Hungarian Plain Volcanic Fields (BBHVF and LHPVF respectively) are located (Martin & Németh 2004).…”