Search Results

You are looking at 1 - 10 of 10 items for

  • Author or Editor: Bernadett Bajnóczi x
  • All content x
Clear All Modify Search

The intraformational paleosol and calcareous muddy cavity fills interbedded in the travertine of the Vár-hegy (Castle Hill) in Budapest were analyzed for carbon and oxygen isotope compositions and compared with the isotope compositions of the host travertine. Microscopic investigations of these layers indicate mechanical reworking of the travertine and mixing with the allothigenic siliciclastic material. Micromorphological features, e.g. needle-fiber calcite, carbonate hypocoatings around pores, ferruginous precipitations and clay infillings in the paleosol and cavity fills indicate that in situ pedogenic processes were active in both layers. The presence of ferrihydrite in the A horizon of the paleosol also supports pedogenic alteration. The stable carbon and oxygen isotope compositions of bulk carbonate of paleosol and cavity fills (d13C= -0.6 to 2.1‰ and d 18O= -16.7 to -12.9‰) are very close to the compositions of the host travertine (d 13C=1.1 to 2.1‰ and d 18O = -17.7 to -13.7‰,) and differ from the probable isotope composition of pedogenic carbonate (d 13C values around -11‰). These results indicate that the studied paleosol and cavity fills have only minor pedogenic component (authigenic carbonate content up to 20%); thus the paleosol represents a weakly developed soil, mostly composed of travertine clasts and allothigenic siliciclastic material.

Restricted access

Abstract

The paper presents an application of carbon isotope analysis in the archaeometric research of graphite-tempered ceramics. Graphite separated from Celtic graphitic ceramics were analysed from Szűr, Szajk and Dunaszentgyörgy archaeological sites from the South Transdanubian region of Hungary. Variation in δ13C values of graphite in the sampling sites is attributed to the characteristics of graphitic metamorphic rock used for tempering. The carbon isotope results will serve as basis for further provenance research on graphite.

Restricted access

Alunites from the low sulfidation-type epithermal systems of the Tokaj and the high sulfidation-type epithermal systems of the Velence Mountains were compared in terms of mineralogical and genetic aspects Na-enriched (1.14 to 2.35% Na2O) tabular alunites from the advanced argillic alteration zones of the Velence Mountains appear in the cavities formed from leached phenocrysts of andesitic rocks. These magmatic-hydrothermal alunites display compositional zoning due to variation in Na and K content and contain Ca-rich phosphate-sulfates with REE elements in their cores (i.e., woodhouseite series). The source of P is probably magmatic apatite that dissolved during intensive leaching of the host rock by acidic magmatic-hydrothermal fluids. Alunites in the steam-heated alteration zones of the Tokaj Mountains appear in the cavities formed from leached pumice fragments of rhyolite tuff units or in fractures in altered rhyolite domes. Rhombohedral and platy alunites have minor Na content (0.02 to 0.61%Na2O) and display compositional zoning due to the variation in Ba content. However, comb alunites contain more Na (1.55 to 1.82% Na2O) and compositional zoning can be attributed to variation of Na and K content. Alunites from the Velence Mountains have much higher d34S values (24.2 to 25.3‰) compared to alunites from the Tokaj Mountains (4.7 to 8.6‰). The d18O values for the sulfate site in the alunite structure are between 10.6 and 13.6‰ in both areas. High d34S values can be attributed to S isotope fractionation during the high temperature magmatic-hydrothermal formation of alunite from the Velence Mountains, which did not occur during formation of low-temperature steam-heated alunites from the Tokaj Mountains.

Restricted access
Acta Ethnographica Hungarica
Authors: Anna Ridovics, Zoltán May, Bernadett Bajnóczi, and Mária Tóth

From the mid-15th century “berettino”, or “turchino”, lighter and darker, deep blue, cobalt-bearing glazes were used on Italian maiolica objects. At first such vessels were made mainly in Faenza, later they spread to Northern Italy and from the 17th century they became popular throughout Europe. According to written sources and archaeological finds, potters working in the Anabaptist-Hutterite settlements used blue glaze right from the start. From the second half of the 17th century there was an increase in the quantity of light and dark blue vessels that were made in many places. In the course of archaeometric research using a handheld X-ray fluorescence spectrometer (XRF), more than 500 Hutterite and Haban objects were analysed; of these circa 140 had a blue glaze. The measurements made on blue glazes and decorations found uranium in addition to cobalt in 107 objects. Some of the 17th century vessels and stove tiles were made in Alvinc (Vinţu de Jos, Romania), Sárospatak, and probably in Szobotist (Sobotište, Slovakia). The vessels with a blue or a white glaze, generally painted roughly with a brush, form a characteristic group provisionally attributed to a “mining town workshop”. Their production began at the end of the 17th century and was passed on by tradition until the 1780s. The workshop probably operated in the vicinity of a mining town in the former Zólyom county, along the upper reaches of the Garam river, in the vicinity of Besztercebánya (Banská Bystrica, Slovakia).

Restricted access
Acta Geologica Hungarica
Authors: Sándor Kele, Lászó Korpás, Attila Demény, Péter Kovács-Pálffy, Bernadett Bajnóczi, and Zsófia Medzihradszky

In the area of the town of Tata (Hungary) there are several Quaternary travertine outcrops, of which the Porhanyó Quarry is the best-exposed one. The travertine of the Porhanyó Quarry can be vertically divided into six units. Algal and other phytoclastic and phytohermal grainstone, boundstone and floatstone are the dominant microfacies. On the walls of the quarry carbonate vents and cones were detected; these forms are indicators of former spring activity at the bottom of a shallow lake. The lake, fed by thermal springs, was formed in a siliciclastic floodplain. The upwelling thermal water brought quartz and other detrital grains from the underlying Pannonian siliciclastic sediments to the surface, concentrating them in the vents. The three main phases of lacustrine evolution were interrupted first by a drying and flooding event, followed by a fluvial-eolian event and finally by eolian sedimentation. The oxygen isotope compositions of the vents differ from the values of vertical sections and slope samples, whereas the carbon isotope compositions show less variation. The different facies migrated during the evolution of the Tata Travertine Complex due to changes in morphology and flow direction. The integrated model of lake evolution suggests an upward cooling climatic trend, beginning with a humid Mediterranean climate in the early phase and closing with a cold, dry continental one in the late phase. The Tata Travertine Complex shows a marked d13C difference from the travertine occurrences of the Buda Mts. that is attributed to local effects. The ascending solutions at Tata may have infiltrated through organic-rich bedrocks and could have carried dissolved C enriched in 12C.

Restricted access
Central European Geology
Authors: Attila Demény, Géza Nagy, Bernadett Bajnóczi, Tibor Németh, József Garai, Vadym Drozd, and Ernst Hegner

Abstract

In this study we report the first hydrogen isotope composition analyses on carbonado diamond along with cathodoluminescence and scanning electron microscopic imaging, electron microprobe analyses, and stable (H and C) and radiogenic (Sr) isotope measurements. The hydrogen of bulk carbonado (consisting diamond and pore-filling minerals) yielded ∼ −4‰, consistent with usual crustal or mantle-derived fluids. The diamond-related hydrogen component is about 70 ± 30 ppm and shows a D-depletion down to −200‰. Determined H isotope values — together with C isotope compositions — overlap the ranges for mantle-derived hydrocarbons. Textural characteristics and Sr isotope ratios of pore-filling florencite indicate that the carbonado was formed in a fluid-rich environment, underwent a significant high-temperature influence and finally suffered thorough alteration. Based on these observations, a terrestrial formation during interaction of mantle rocks/melts or subducted crustal materials and reduced C-H fluids seems to be more plausible than an extraterrestrial origin.

Restricted access

Abstract

Stable carbon and oxygen isotope compositions of living Unio shells and oxygen isotope compositions of water samples were determined in order to demonstrate how the shells' compositions can reflect environmental conditions. With this information in hand, fossil shell fragments from a sedimentary section at Tiszapüspöki covering the period of about 3.5 to 10 ky BP were analyzed for their stable isotope as well as trace element compositions. Beside the determination of sedimentary facies effects on the geochemical compositions, the combined evaluation of isotopic and trace element records allowed us to detect past environmental changes at a millennial scale. The data indicate that the period of 6 to 8 ky BP was characterized by humid summers that — on the basis of comparison with an Alpine speleothem record — was associated with a generally warmer climate and increased winter precipitation in the Alps.

Restricted access

The Hutterites and Habans produced coloured-glazed, mostly blue- and yellow-coloured vessels alongside their white-glazed faience ware. However, the production technology of the coloured-glazed vessels, specifically the nature of the glaze, is a matter of debate among scholars. Both coloured tin glaze and coloured engobe covered with a transparent lead glaze were thought to have been applied on the ceramics.

Around 140 objects of blue-glazed Hutterite and Haban museum objects and archaeological artefacts were analysed using a handheld XRF spectrometer. In addition, small fragments of selected ceramics were studied by electron microprobe analysis (EMPA).

According to the XRF measurements the blue glaze of all except one of the studied Hutterite and Haban ceramics contains tin in variable amounts (from about 0.015 wt% up to 13 wt%). The EMPA technique showed that tin in the form of tin oxide opacifier was deliberately added to the single-layered alkali– lead or lead–alkali glaze. These data confirm that the tin glaze technique was used during production of blue-glazed ceramics, and in this respect they can be regarded as faience. The blue glaze of the Haban vessels produced by a “mining town” workshop contains tin in very low concentrations (Sn <0.2 wt% by XRF), therefore the opacity of the glaze is mainly caused by the abundant silica and arsenate particles.

Restricted access
Central European Geology
Authors: Attila Demény, Gabriella Schöll-Barna, Pál Sümegi, Péter Sipos, István Fórizs, Brigitta Réka Balázs, Bernadett Bajnóczi, and Gordon Cook

Abstract

In this paper we present sedimentological and geochemical data for a section of fluvial deposits from SE Hungary covering the period from about 20 to 5 ky BP. Major and trace element geochemistry of bulk sediments as well as stable C and O isotope compositions of the carbonate content indicate significant changes in depositional facies and/or sediment provenance as well as climate conditions. Variations in bulk sediment Sr, TiO2 and P2O5 concentrations were correlated with major climate change events following the Late Glacial Maximum that support the age model established on the basis of AMS 14C age data. Bulk sediment Sr concentrations and stable C and O isotope compositions of bulk sediment carbonate were determined by changes in denudation of carbonate rocks in the recharge area. The Sr and C-O isotope patterns show correlations with global temperature changes during the Pleistocene-Holocene transition. However, TiO2 and P2O5 contents show correspondence with humidity changes, suggesting variations in chemical weathering. In addition to the sedimentological effects, C and O isotope compositions of Unio crassus shell fragments show strong changes at the Pleistocene-Holocene transition, indicating that the bivalve shells can reflect climate conditions. On the other hand, shorter climate change events were difficult to track in the isotope records due to the competing fractionation processes. The combined evaluation of chemical and isotopic compositions revealed that beside the globally important Younger Dryas and Bølling/Allerød periods, the Ságvár-Lascaux interstadial was of local importance, in accordance with earlier studies.

Restricted access