Cent. Eur. J. Geosci. • 2(3) • 2010 • 207-270 DOI: 10.2478/v10085-010-0024-5 Central European Journal of Geosciences Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review Review Article Jaroslav Lexa1∗, Ioan Seghedi2, Károly Németh3, Alexandru Szakács24, Vlastimil Koneˇcný5, Zoltán Pécskay6, Alexandrina Fülöp7, Marinel Kovacs7 1 Geological Institute of the Slovak Academy of Sciences, Bratislava, Slovakia, 2 Institute of Geodynamics, Romanian Academy, Bucharest, Romania 3 Volcanic Risk Solutions CS-INR, Massey University, Palmerston North, NewZealand, 4 Sapientia University, Dept. of Environmental Sciences, Cluj-Napoca, Romania 5 State Geological Institute of D. Štúr, Bratislava, Slovakia 6 Institute of Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary 7 North University, Faculty of Mineral Resources, Baia Mare, Romania Received 27 May 2010; accepted 18 July 2010 207 Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review Abstract: Neogene to Quaternary volcanic/magmatic activity in the Carpathian-Pannonian Region (CPR) occurred be- tween 21 and 0.1 Ma with a distinct migration in time from west to east. It shows a diverse compositional variation in response to a complex interplay of subduction with roll-back, back-arc extension, collision, slab break-off, delamination, strike-slip tectonics and microplate rotations, as well as in response to further evo- lution of magmas in the crustal environment by processes of differentiation, crustal contamination, anatexis and magma mixing. Since most of the primary volcanic forms have been affected by erosion, especially in areas of post-volcanic uplift, based on the level of erosion we distinguish: (1) areas eroded to the basement level, where paleovolcanic reconstruction is not possible; (2) deeply eroded volcanic forms with secondary morphology and possible paleovolcanic reconstruction; (3) eroded volcanic forms with remnants of original morphology preserved; and (4) the least eroded volcanic forms with original morphology quite well preserved. The large variety of volcanic forms present in the area can be grouped in a) monogenetic volcanoes and b) polygenetic volcanoes and their subsurface/intrusive counterparts that belong to various rock series found in the CPR such as calc-alkaline magmatic rock-types (felsic, intermediate and mafic varieties) and alkalic types including K-alkalic, shoshonitic, ultrapotassic and Na-alkalic. The following volcanic/subvolcanic forms have been identified: (i) domes, shield volcanoes, effusive cones, pyroclastic cones, stratovolcanoes and calderas with associated intrusive bodies for intermediate and basic calc-alkaline volcanism; (ii) domes, calderas and ignimbrite/ash-flow fields for felsic calc-alkaline volcanism and (iii) dome flows, shield volcanoes, maars, tuff- cone/tuff-rings, scoria-cones with or without related lava flow/field and their erosional or subsurface forms (necks/ plugs, dykes, shallow intrusions, diatreme, lava lake) for various types of K- and Na-alkalic and ultra- potassic magmatism. Finally, we provide a summary of the eruptive history and distribution of volcanic forms in the CPR using several sub-region schemes. Keywords: Carpathians • Pannonian Basin • volcanoes • volcanic forms • Neogene • Quaternary • alkali basalts • andesites • dacites • rhyolite © Versita Warsaw 1. Introduction a laterally short distance small-volume monogenetic vol- canoes to mighty stratovolcanoes and extensive ignimbrite sheets likely associated with large calderas. In this paper we provide a summary of known volcanic features docu- Volcanism in the Carpathian-Pannonian Region (CPR) mented in the past decades in the CPR. Such documenta- was active since the early Miocene through various phases tion has a strong scientific value to identify key elements in variable geotectonic and magmatic settings. As a re- of volcanism in a collisional zone that was active since the sult the CPR today is considered to be a well-defined, early Miocene until present and which, in certain parts, is but relatively small region where changes of geotectonic considered still active. The time aspect of understanding and magmatic situations from subduction related arc vol- CPR volcanic history and its volcanism is significant due canism to back-arc intraplate volcanism took place in a to the fact that the CPR represents a nearly completed confined region. While modern arc and back arc settings sequence of volcanism associated with subducting litho- are tempting areas to pursue volcanic research that com- spheric slabs, back-arc extension, and post-subduction in- monly have a strong natural hazard element, such young traplate volcanism as a reflection of gradual geotectonic volcanic regions prevent access to cores and deep zones of changes over the last 21 million years. Such complete vol- volcanoes due to their young age. The CPR in this respect canic history of a syn- and post-collisional tectonic regime provides an advantage due to its mature and commonly related volcanism is rare, and therefore makes the CPR a erosion-modified volcanic landforms to see the deeper ar- unique region that could be compared with other geotec- chitecture of formed volcanoes as well as their succession. tonically similar volcanic regions. In addition the confined nature of the CPR provides a The review of volcanic forms in the Carpathian-Pannonian unique opportunity to study nearly every possible mani- Region (CPR) presented here is meant to complement festation of known volcanism. Such small size is compara- previous geological, geophysical and petrological inves- ble with a small modern volcanic arc segment such as the tigations. Reviews have been published treating the Caribean or Vanuatu volcanic arc, but the CPR in the same space/time evolution of volcanic activity [1, 2], geotectonic area provides an opportunity to see not only deep into its evolution [3] and petrology and geodynamic setting of vol- eroded volcanic landforms’ deeper structures, but also in canic activity [4–7]. That is the reason that these subjects are covered only in the extent necessary for a proper un- ∗E-mail: [email protected] derstanding of volcanic form presentation. 208 Jaroslav Lexa, Ioan Seghedi, Károly Németh, Alexandru Szakács, Vlastimil Koneˇcný, Zoltán Pécskay, Alexandrina Fülöp, Marinel Kovacs Figure 1. Distribution of volcanic formations in the Carpathian/Pannonian Region (CPR). Numbers indicate sub-regions discussed in the text. Modified after Figure 1, Pécskay et al. [2]. Knowledge of volcanic form patterns provides informa- ranges and similarities. While timing of volcanic activ- tion about the spatial availability of magma, evolution ity is known from a map-based stratigraphy and detailed of magma in various size chambers and ascent of magma geochronology [1, 2], paleovolcanic reconstruction of vol- through geologically contrasting fragments of the crust. canic forms is based on several decades of practice and Distribution, storage, ascent, and eruption of magmas collaboration. We provide characteristics of volcanic forms were complex, resulting in a remarkable variety of com- and a summary of the eruptive history and volcanic form positions generating various volcanic forms. Naturally, distribution in the CPR using seven sub-region schemes volcanic forms reflect also an environment of their evo- as in Figure 1: 1 – Styermark + Burgenland + Little lution that was mostly terrestrial and partly subaqueous Hungarian Plain + Balaton Highlands; 2 – Central Slo- (e.g. shallow marine). Further complication comes with vakia Volcanic Field + Börzsöny-Visegrád-Pilis-Burda + the extent of erosion. Based on the level of erosion we Cserhát-Mátra + Bükk foreland + Southern Slovakia – distinguish: (1) areas eroded to the basement level, where Northern Hungary; 3 – Moravia + Pieniny; 4 – Tokaj- paleovolcanic reconstruction is not possible; (2) deeply Zemplín + Slanské vrchy + Vihorlat-Gutin + Beregovo eroded volcanic forms with purely erosional morphology, + Oaș + Gutâi; 5 – Apuseni; 6 – Ţibleș-Rodna; 7 – where paleovolcanic reconstruction is still possible; (3) Calimani˘ + Gurghiu + Harghita + Perșani. For each eroded volcanic forms with remnants of original morphol- of the sub-regions we consider also succession, composi- ogy preserved and recognizable; and (4) the least eroded tional characteristics, extent of erosion and vent distribu- volcanic forms with original morphology quite well pre- tion patterns. served. Our presentation is based on trustworthy data for all the volcanoes in the time interval they have evolved (i.e., <21 Ma), outlining their distribution, their compositional 209 Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review 2. Geotectonic setting mostly medium to high-K type andesites, compa- rable with andesites of continental margins. Rocks During Neogene time the Carpathian orogenic arc rep- vary from basaltic andesites to rhyolites, often in resented a continental margin or evolved island arc with the bi-modal type of suites. The most frequent vol- variable parts of older continental crust. The arc migrated canic forms are monogenetic volcanic cones, com- northward, northeastward and eastward due to subduction posite stratovolcanoes, effusive fields, dome/flow of oceanic and suboceanic crust of fore-arc flysch basins complexes and subvolcanic intrusive complexes. until it collided with the margin of the European Platform. The collision gradually evolved from the west to the east. • Intermediate calc-alkaline volcanic forms