Basic research

FUKSI, TomášTOMAŠOVÝCH, Adam – GALLMETZER, Ivo – HASELMAIR, Alexandra – ZUSCHIN, Martin. 20th century increase in body size of a hypoxia-tolerant bivalve documented by sediment cores from the northern Adriatic Sea (Gulf of Trieste). In Marine Pollution Bulletin, 2018, vol. 135, p. 361-375. (3.241 – IF2017). (2018 – Current Contents). ISSN 0025-326X.

TOMAŠOVÝCH, Adam – GALLMETZER, Ivo – HASELMAIR, Alexandra – KAUFMAN, D. S. – KRALJ, Martina – CASSIN, Daniele – ZONTA, Roberto – ZUSCHIN, Martin. Tracing the effects of eutrophication on molluscan communities in sediment cores: outbreaks of an opportunistic species coincide with reduced bioturbation and high frequency of hypoxia in the Adriatic Sea. In Paleobiology, 2018, vol. 44, no. 4, p. 575-602. (2.400 – IF2017). (2018 – Current Contents). ISSN 0094-8373.

Sediment cores show that population density of the bivalve Corbula gibba in the northern Adriatic Sea increased significantly in the late 20th century, owing to strong eutrophication (that propagated into higher contents of total organic carbon and nitrogen in sediments) and a strong increase in the frequency of hypoxic events.

Estimating the effects and timing of anthropogenic impacts on the composition of macrobenthic communities is challenging because the 19th and the early 20th-century biological surveys are sparse and the corresponding intervals in sedimentary sequences are mixed by bioturbation. To assess the effects of eutrophication and hypoxia on macrobenthic communities in the northern Adriatic Sea, we analyzed sizes and abundances of molluscan assemblages in sediment cores collected at 10-20 m water depths. We showed that, first, pervasively bioturbated muds typical of highstand conditions deposited in the early twentieth century were replaced by muds with relicts of flood layers and high content of total organic carbon deposited in the late twentieth century. Second, dating of Corbula gibba shells shows that the shift from the early to the late twentieth century is characterized by a decrease in stratigraphic disorder and by an increase in temporal resolution of assemblages from ∼25–50 years to ∼10–20 years. This shift reflects a decline in the depth of the fully mixed layer from more than 20 cm to a few centimeters. Third, the increase in shell size and abundance of the opportunistic species C. gibba and the extinction of hypoxia-sensitive species coincided with the decline in bioturbation and higher frequency of seasonal hypoxia in both regions.

KRISTEK, Jozef - MOCZO, Peter - BARD, Pierre Yves - HOLLENDER, Fabrice - STRIPAJOVA, Svetlana. Computation of amplification factor of earthquake ground motion for a local sedimentary structure. In Bulletin of Earthquake Engineering, 2018, vol. 16, no. 6, p. 2451-245. (2.303 - IF2017). (2018 - Current Contents). ISSN 1570-761X.

MOCZO, Peter - KRISTEK, Jozef - BARD, Pierre Yves - STRIPAJOVA, Svetlana - HOLLENDER, Fabrice - CHOVANOVÁ, Zuzana - KRISTEKOVÁ, Miriam - SICILIA, Deborah. Key structural parameters affecting earthquake ground motion in 2D and 3D sedimentary structures. In Bulletin of Earthquake Engineering, 2018, vol. 16, no. 6, p. 1421-2450. (2.303 - IF2017). (2018 - Current Contents). ISSN 1570-761X.

2D/1D aggravation factor for amplification of cumulative absolute velocity for all profiles ordered according to the value of the shape ratio (maximum sediment thickness over width). An additional colour code is provided as an index for the sediment/bedrock velocity contrast.

Alluvial valleys generate strong effects on earthquake ground motion (EGM). These effects are rarely accounted for even in site-specific studies because of (a) the cost of the required geophysical surveys to constrain the site model, (b) lack of data for empirical prediction, and (c) poor knowledge of the key controlling parameters. We performed 3D, 2D and 1D simulations for six typical sedimentary valleys of various width and depth, and for a variety of modifications of these 6 “nominal models” to investigate sensitivity of EGM characteristics to impedance contrast, attenuation, velocity gradient and geometry. We calculated amplification factors, and 2D/1D and 3D/2D aggravation factors for 10 EGM characteristics, using a representative set of recorded accelerograms to account for input motion variability (The methodology is presented in the first article). For all investigated sites, there is always an area in the valley for which 1D estimates are not sufficient. 2D estimates are insufficient at several sites. The identified key structural parameters are the shape ratio and overall geometry of the sediment-bedrock interface, impedance contrast at the sediment-bedrock interface, and attenuation in sediments. We showed that the amplification factors may largely exceed the values that are usually considered in GMPEs between soft soils and rock sites.

PÁNISOVÁ, Jaroslava - BALÁZS, A. - ZALAI, Z. - BIELIK, Miroslav - HORVÁTH, Ferenc - HARANGI, Szabolcs - SCHMIDT, Sabine - GÖTZE, Hans-Jürgen. Intraplate volcanism in the Danube basin of NW Hungary: 3D geophysical modelling of the Late Miocene Pásztori volcano. In International Journal of Earth Sciences, 2018, vol. 107, no. 5, p. 1713-1730. (2.276 - IF2017). (2018 - Current Contents). ISSN 1437-3254.

Four selected cross sections of the Pásztori volcano final model.
3D geophysical model of the Pásztori volcano: south view (a), east view (b)

For the 3-D geophysical modelling of the early Late Miocene Pásztori volcano (∼11–10 Ma) in the volcanic field of the Lower Hungarian Plain, belonging to the Danube basin, gravitational and magnetic data, seismic reflection sections and drilling data in combination with the latest geological knowledge were used. Petrological analysis of rock samples from the cores of six exploration boreholes has found that volcanic rocks are built by alkaline trachytic and trachyandesitic volcanoclastic and effusive rocks. The measured magnetic susceptibilities of these samples showed that they are generally characterized by very low magnetization, indicating their deeper magnetic source. The created 3-D model of the Danube basin correlates very well with the observed high magnetic anomalies ΔZ above the volcano until the complete Bouguer anomaly correlates better with the crystalline basement depth. The model of the volcano consists of three magnetic sources. The nearest source to the surface is built by volcanoclastic and its thickness is 0.3–1.8 km. The second one is composed of trachytic-trachyandesitic and volcanoclastic rocks with a maximum thickness of 2 km and their minimum deposition is at a depth of 2.3 km. The deepest source is represented by a deep magmatic pluton located at a depth of 5–15 km. The results obtained significantly contributed to the expansion of the knowledge on crustal structure and the evolution of the Danube basin, which was accompanied by alkaline intraplate volcanism.

Applied research

CHOVANOVÁ, Zuzana - KRISTEK, Jozef. A local magnitude scale for Slovakia, Central Europe. In Bulletin of the Seismological Society of America, 2018, vol. 108, no. 5A, p. 2756-2763. (2.343 - IF2017). (2018 - Current Contents). ISSN 0037-1106.

Each country or region should have its own formula for estimating a local magnitude of local earthquakes which consistently reflects the seismic attenuation behavior of the region. Until now, the Hutton and Boore (1987) scale derived for Southern California was used for local magnitude estimation in Slovakia because of similar attenuation properties of the regions. We have determined the distance correction term and the attenuation term of the local magnitude scale from collected trace amplitudes of earthquakes recorded by the National Network of Seismic Stations (NNSS) from 2005 to 2016 using linear regression analysis. Additionally the station corrections for the nine seismic stations of NNSS have been estimated for the first time. Using the newly determined scale reduces error by up to 58% compared to the formula previously used. Since both local magnitude formula and ground motion prediction equation (GMPE) are attenuation relationships, their similarity can be used in seismic hazard analysis.

MAJCIN, Dušan - BEZÁK, Vladimír - KLANICA, Radek - VOZÁR, Ján - PEK, Josef - BILČÍK, Dušan - TELECKÝ, Josef. Klippen Belt, Flysch Belt and Inner Western Carpathian Paleogene Basin Relations in the Northern Slovakia by Magnetotelluric Imaging. In Pure and Applied Geophysics, 2018, vol. 175, p. 3555-3568. (1.652 - IF2017). (2018 - Current Contents). ISSN 0033-4553.

Geological interpretation of the magnetotelluric profile SL-1 based on 2D modeling results (in upper cross-section resistivity distribution) and that one taken from 3D model (in lower part of the figure). FB Flysch Belt, KB Klippen Belt, PC Peninic Crust, ICP Inner Carpathian Paleogene, M Mesozoic complexes, TCr Crystalline rocks of Tatricum. Letter in circle - position references to hydrogeological structures.

The structural model of the space relations of the Klippen Belt with the Inner Carpathian Paleogene and also with Outer Flysch Belt units was constructed on the base of the magnetotelluric measurements interpretation in the region near Stará Ľubovňa. The research includes also hydrogeological structures of the studied region and the relations to the Ružbachy horst structures. The results have direct application at appraisal of the geothermal energy source parameters within the studied region. We used the innovative approach for interpretation of the MT measurements from independent 2D and 3D models of the electric conductivity distribution models in upper parts of the Earth crust and another geological and geophysical knowledge.

MAJZLAN, Juraj - ŠTEVKO, Martin - CHOVAN, Martin - LUPTÁKOVÁ, Jarmila - MILOVSKÁ, Stanislava - MILOVSKÝ, Rastislav - JELEŇ, Stanislav - SÝKOROVÁ, Martina - POLLOK, Kilian - GÖTTLICHER, Jörg - KUPKA, Daniel. Mineralogy and geochemistry of the copper-dominated neutral mine drainage at the Cu deposit Ľubietová-Podlipa (Slovakia). In Applied Geochemistry, 2018, vol. 92, p. 59-70. (3.088 - IF2017). (2018 - Current Contents). ISSN 0883-2927.

Langite crystals on the rock fragments (a, b) and copper-rich gel on the stream in the Jacobi adit (c, d).

The neutral mine drainage system at Ľubietová is dominated by copper and sulfate. It is generated by oxidative dissolution of chalcopyrite, as confirmed by sulfur isotopes. Its neutral nature is maintained by buffering via the primary carbonates. The oxidation zone, composed of Cu phosphates and carbonates (libethenite, pseudomalachite, malachite) plays minor role in the mine drainage generation. The water is discharged through the lowermost adits in the ore field; inside the adit, blue gel covers the stream and converts slowly to crystalline copper sulfate - langite. Outside the adits, redox cycling of Cu was observed. Nanocrystals of native copper crystalize on rock-forming minerals. Cu content is reduced by factor of 100 when mine drainage after 1 km reaches the river. Sulfur isotopes document that no copper sulfides are precipitating; but sulfates or carbonates. The natural attenuation could be responsible for the enrichment of sediments with copper (about few metric tons in size).

Research related to international collaboration

HURAI, Vratislav - HURAIOVÁ, Monika - GAJDOŠOVÁ, Michaela - KONEČNÝ, Patrik - SLOBODNÍK, Marek - SIEGFRIED, Pete. Compositional variations of zirconolite from the Evate apatite deposit (Mozambique) as an indicator of magmatic-hydrothermal conditions during post-orogenic collapse of Gondwana. In Mineralogy and Petrology, 2018, vol. 112, no. 3, p. 279-296. (1.664 - IF2017). (2018 - Current Contents). ISSN 0930-0708.

Crystallization of Cambrian zirconolite CaZrTi2O7 (zrl, yellow) onto late-Proterozoic baddeleyite (bdy, orange) in the Evate apatite-carbonatite deposit, Mozambique. Other minerals: zircon ZrSiO4 (zrn), magnetite Fe3O4 (mt), calcite CaCO3 (cal), dolomite CaMg(CO3)2 (dol), anhydrite CaSO4 (anh), fluorapatite Ca5(PO4)3F (ap).

Hitherto unknown REE- and U-Th-rich zirconolite types have been described in the Evate apatite-magnetite-carbonate deposit in eastern Mozambique. Both zirconolite types contain locally increased Nb and Ta concentrations (up to 6 wt. % Nb2O5+Ta2O5). Fe3+ predominates over Fe2+ in all zirconolite types, thus enabling the high REE content (28 wt. % REE2O3 in Nb-poor zirconolites to be stored in locally dominant REEZrTiFe3+O7 component known so far only as a synthetic analogue of natural zirconolite. Other zirconolite types are dominated by the common CaZrTi2O7 end member, but the “synthetic” REEZrTiFe3+O7 and another “synthetic” (U,Th)ZrFe3+2O7 component are also abundant. U-Pb-Th age of early U,Th-zirconolite corresponds to 485±9 Ma. Substitutional trends of the REE-zirconolite overlap magmatic deposits associated with carbonatites and syenites, whereas the U,Th-zirconolite is compositionally similar to that from hydrothermal-metasomatic deposits. The predominance of Fe3+ in zirconolite reflects oxidizing fluids percolated during Ordovician-Cambrian rifting of Gondwana.

KOHÚT, Milan - HOFMANN, Mandy - HAVRILA, Milan - LINNEMANN, Ulf - HAVRILA, Jakub. Tracking an upper limit of the "Carnian Crisis" and/or Carnian stage in the Western Carpathians (Slovakia). In International Journal of Earth Sciences, 2018, vol. 107, no. 1, p. 321-335. (2.276 - IF2017). (2018 - Current Contents). ISSN 1437-3254.

The paper deals with the study of detrital zircons and their dating with the help of LA ICP-MS from the Lunz Formation of the Western Carpathians. The work was realized in the framework of the scientific collaboration with the Senckenberg Naturhistorische Sammlungen, Museum for Mineralogy and Geology, Geochemistry Section, Königsbrücker Landstrasse, Dresden, Germany (Prof. Ulf Linnemann and Dr. Mandy Hofmann). We found with German colleagues, that these clastic sediments were derived from several sources, especially: a) from the recycled Variscan orogen; b) from the remote East European Platform; and c) from the contemporaneous Triassic volcanic sources so called Pietra Verde. The Lunz Formation – marine delta sediments represents a typical product of the “Carnian Crisis”—a major climate change and biotic turnover that occurred during the Carnian stage in the Tethys Ocean within the carbonate shelf and intrashelf basins in the Northern Calcareous Alps and the Western Carpathians. The current age of the Carnian–Norian boundary is listed on the International Chronostratigraphic Chart (International Commission on Stratigraphy 2017 Edition) at ca. 227 Ma. However, our the Pietra Verde vulcanite zircon age determination (221.2 ± 1.6 Ma) separated from the synchronous Lunz Formation of the Western Carpathians, shifts the age of the Carnian–Norian boundary ca. 6 Million years earlier at ca. 221 Ma ago. The importance of the paper is because this is the first time used of a detrital zircon dating for real stratigraphic determination in the entire Alpine-Carpathian realm.

RAVNA, Erling J. Krogh - ZOZULYA, Dmitry - KULLERUD, K. - CORFU, F. - NABELEK, Peter - JANÁK, Marian - SLAGSTAD, Trond - DAVIDSEN, Børre - SELBEKK, Rune S. - SCHERTL, Hans-Peter. Deep-seated Carbonatite Intrusion and Metasomatism in the UHP Tromsø Nappe, Northern Scandinavian Caledonides - a Natural Example of Generation of Carbonatite from Carbonated Eclogite. In Journal of Petrology, 2017, vol. 58, no. 12, p. 2403-2428. (3.280 - IF2016). (2017 - Current Contents). ISSN 0022-3530.

Carbonatites (sensu stricto) are igneous rocks typically associated with continental rifts, being emplaced at relatively shallow crustal levels or as extrusive rocks. Some carbonatites are, however, related to subduction and lithospheric collision zones, but so far no carbonatite has been reported from ultrahigh-pressure metamorphic terrains. In this study (Ravna et al., 2017) we present detailed petrological and geochemical data on carbonatites from the Nappe – an ultrahigh-pressure metamorphic terrain in the Scandinavian Caledonides. We suggest that the primary carbonatite magma resulted from partial melting of a carbonated eclogite at ultrahigh pressure, in a deeply subducted continental slab. Microdiamonds found in gneisses (Janák et al. ,2013) intruded by carbonatite are often associated with carbonates, hence formation of diamond by crystallization from carbonatite melt was likely.