Szabolcs Harangi

Review of Neogene and Quaternary volcanism of the Carpathian-Pannonian region

A machine tool with additional tool magazine is described wherein a tool magazine for special tools is arranged below the spindle with the tools held parallel to the spindle axis and inserted directly from the magazine into the spindle. The magazine is a drum which rotates around an axis parallel to the spindle axis and slides in the direction of this axis with axially parallel fixing grooves for the tool.

Distal deposition of tephra from the Eyjafjallajökull 2010 summit eruption

The 2010 Eyjafjallajokull lasted 39 days and had 4 different phases, of which the first and third (14-18 April and 5-6 May) were most intense. Most of this period was dominated by winds with a northerly component that carried tephra toward Europe, where it was deposited in a number of locations and was sampled by rain gauges or buckets, surface swabs, sticky-tape samples and air filtering. In the UK, tephra was collected from each of the Phases 1-3 with a combined range of latitudes spanning the length of the country. The modal grain size of tephra in the rain gauge samples was 25 mu m, but the largest grains were 100 mu m in diameter and highly vesicular. The mass loading was equivalent to 8-218 shards cm(-2), which is comparable to tephra layers from much larger past eruptions. Falling tephra was collected on sticky tape in the English Midlands on 19, 20 and 21st April (Phase 2), and was dominated by aggregate clasts (mean diameter 85 mu m, component grains <10 mu m). SEM-EDS spectra for aggregate grains contained an extra peak for sulphur, when compared to control samples from the volcano, indicating that they were cemented by sulphur-rich minerals e. g. gypsum (CaSO4 center dot H2O). Air quality monitoring stations did not record fluctuations in hourly PM10 concentrations outside the normal range of variability during the eruption, but there was a small increase in 24-hour running mean concentration from 21-24 April (Phase 2). Deposition of tephra from Phase 2 in the UK indicates that transport of tephra from Iceland is possible even for small eruption plumes given suitable wind conditions. The presence of relatively coarse grains adds uncertainty to concentration estimates from air quality sensors, which are most sensitive to grain sizes <10 mu m. Elsewhere, tephra was collected from roofs and vehicles in the Faroe Islands (mean grain size 40 mu m, but 100 mu m common), from rainwater in Bergen in Norway (23-91 mu m) and in air filters in Budapest, Hungary (2-6 mu m). A map is presented summarizing these and other recently published examples of distal tephra deposition from the Eyjafjallajokull eruption. It demonstrates that most tephra deposited on mainland Europe was produced in the highly explosive Phase 1 and was carried there in 2-3 days.

Mesozoic Igneous Suites in Hungary: Implications for Genesis and Tectonic Setting in the Northwestern Part of Tethys

Mesozoic igneous rocks occur in various tectonic units of the Intra-Carpathian Area of Eastern Europe. These rocks were situated several hundred km apart from one another during their formation, and subsequent large lateral displacements resulted in their present positions. They formed during a relatively wide temporal range (Middle Triassic to Late Cretaceous) through different petrogenetic processes associated with the Mesozoic evolution of the northwestern part of Tethys. In the Transdanubian subunit of the Alcapa block, Middle Triassic calc-alkaline, intermediate-to-acidic, and potassic rocks occur as pyroclastics, lava flows, and dikes in the Bakony and Buda mountains. The Gemer-Bukk subunit of the Alcapa block comprises two different igneous series: (1) slightly metamorphosed Middle Triassic volcanic rocks of the Eastern Bukk Mountains, which can be divided into an older (Anisian-Early Ladinian) calc-alkaline, intermediate-to-acidic volcanic series and a younger (Late Ladinian) alkaline basaltic ser...

Radiocarbon dating of the last volcanic eruptions of Ciomadul Volcano, southeast carpathians, Eastern-Central Europe

This paper provides new accelerator mass spectrometry (AMS) radiocarbon age data for the last volcanic events in the Carpathian-Pannonian region of eastern-central Europe. The eruption ages were determined on charcoal fragments collected from pumiceous pyroclastic flow deposits at 2 localities of the Ciomadul Volcano. Two charcoal samples from the southeastern margin of the volcano (Bixad locality) set the date of the last volcanic eruption to 27,200 ± 260 yr BP (29,500 ± 260 cal BC). On the other hand, our data show that the Tusnad pyroclastic flow deposit, previously considered as representing the youngest volcanic rock of the region, erupted at ~39,000 yr BP (~41,300 cal BC). Thus, a period of dormancy more than 10,000 yr long might have elapsed between the 2 volcanic events. The different ages of the Tusnad and Bixad pyroclastic flow deposits are confirmed also by the geochemical data. The bulk pumices, groundmass glass, and the composition of the main mineral phases (plagioclase and amphibole) suggest eruption of slightly different magmas. Considering also the assumed long volcanic history (~600 ka) of the Ciomadul, these data suggest that further detailed studies are necessary on this seemingly inactive volcano in order to evaluate the possible renewal of volcanic activity in the future.

Volcanic Heritage of the Carpathian–Pannonian Region in Eastern-Central Europe

The Carpathian-Pannonian Region in eastern-central Europe provides a unique insight into a wide range of volcanic phenomena. Eruptions of various magmas occurred here during the last 20 million years and the last volcanic eruption took place only 30 thousand years ago. Post-volcanic erosion revealed nicely the inner structure of the volcanic edifices and preserved almost all of the typical volcanic formations characterize the basaltic through andesitic-dacitic to rhyolitic volcanism. The volcanic heritage meets with cultural, historic, gastronomic and winery pleasures and hospitality of local people. Geotourism is a developing area here supported by two new Geoparks, both based primarily on volcanic heritage and a unique thematic Volcano Park.

LA-ICP-MS U-Pb zircon geochronology data of the Early to Mid-Miocene syn-extensional massive silicic volcanism in the Pannonian Basin (East-Central Europe)

This article provides LA-ICP-MS in-situ U-Pb zircon dates performed on single crystals from dacitic to rhyolitic ignimbrites of the Bükkalja Volcanic Field (Hungary, East-Central Europe) temporally covering the main period of the Neogene silicic volcanic activity in the Pannonian Basin. The data include drift-corrected, alpha dose-corrected, Th-disequilibrium-corrected, and filtered data for geochronological use. The data presented in this article are interpreted and discussed in the research article entitled “Early to Mid-Miocene syn-extensional massive silicic volcanism in the Pannonian Basin (East-Central Europe): eruption chronology, correlation potential and geodynamic implications” by Lukács et al. (2018) [1].

LA-ICP-MS and SIMS U-Pb and U-Th zircon geochronological data of Late Pleistocene lava domes of the Ciomadul Volcanic Dome Complex (Eastern Carpathians)

This article provides laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and secondary ionization mass spectrometry (SIMS) U-Pb and U-Th zircon dates for crystals separated from Late Pleistocene dacitic lava dome rocks of the Ciomadul Volcanic Dome Complex (Eastern Carpathians, Romania). The analyses were performed on unpolished zircon prism faces (termed rim analyses) and on crystal interiors exposed through mechanical grinding an polishing (interior analyses). 206Pb/238U ages are corrected for Th-disequilibrium based on published and calculated distribution coefficients for U and Th using average whole-rock and individually analyzed zircon compositions. The data presented in this article were used for the Th-disequilibrium correction of (U-Th)/He zircon geochronology data in the research article entitled “The onset of the volcanism in the Ciomadul Volcanic Dome Complex (Eastern Carpathians): eruption chronology and magma type variation” (Molnár et al., 2018) [1].

G. R. Foulger. Plates vs. Plumes: A geological controversy

Volcanoes were always in the centre of the thinking of early natural philosophers, and remain of interest to modern scientists. Great debates in the earth sciences focused on the origin of volcanic and plutonic rocks, such as occurred between the neptunists and plutonists in the eighteenth century and the so-called granite controversy during the first half of the twentieth century. How do volcanoes work? What controls their geographic distribution and what is the triggering mechanism of melt generation? The plate tectonic theory provides rational answers to these questions, but still a significant number of volcanoes remain for which the answers are not straightforward. Most of them are located within oceanic and continental plates. They involve some very productive volcanoes, such as in Hawaii and the Réunion islands, but also the small-volume basaltic volcanoes of many monogenetic volcanic fields. The ultimate reason for the long-lasting but intermittent volcanism in the latter, for example in Arizona and Nevada in the USA, in the Michoacán-Guanajuato region in Mexico, around Auckland in New Zealand and in the Eifel and the Pannonian Basin in Europe, is still unresolved, which makes it difficult to predict any future volcanic events. A convenient explanation for the activity of all of these diverse volcanoes is deep mantle upwelling, i.e. a mantle plume. J. Tuzo Wilson introduced the “hot spot” idea in 1963, just in the advent of the plate tectonic model, followed by the proposition of the plume concept by W. Jason Morgan in 1971. This new theory was an elegant explanation for the origin of the volcanoes, which are located away from plate boundaries. Buoyant hot solid rock has been inferred to rise from the core–mantle boundary, where remnants of ancient subducted slab material had been accumulated, and as such a cylindrical upwelling approaches the shallow depths beneath the lithosphere, partial melting begins and gives rise to mafic magmas, which feed volcanoes. Just as the plate tectonic concept has become a useful paradigm in the earth sciences, providing a strong framework for our thinking, the plume hypothesis has been also widely accepted, because it explains well the origin of intraplate magmatism. In many cases, however, it is regarded not as a possible model or hypothesis, Editorial responsibility: K. Németh