Norbert Zajzon

CAPITANIAN (MIDDLE PERMIAN) MASS EXTINCTION AND RECOVERY IN WESTERN TETHYS: A FOSSIL, FACIES, AND δ13C STUDY FROM HUNGARY AND HYDRA ISLAND (GREECE)

Abstract The Capitanian (middle Permian) extinction and recovery event is examined in carbonate platform settings from western Tethys (Hungary and Hydra, Greece). The age model for these sections is poorly resolved and we have constructed a &dgr;13C chemostratigraphic correlation scheme, supported by conodont and foraminifer data, which attempts correlation with the well-dated events in China. This reveals the timing of events was similar in all Tethyan regions: extinction losses in the middle of the Capitanian produced late Capitanian assemblages in Hungary and Hydra with a distinctive late Permian character (for example, they lack large fusulinaceans). There is no evidence for an extinction event at the end of the Guadalupian (Capitanian) suggesting that previous claims for an end-Guadalupian mass extinction are based on poorly dated records of a mid-Capitanian event. Base level was stable through much of the middle–late Permian transition with the exception of a major regression within the Capitanian Stage. The subsequent transgression established widespread shallow-water carbonate deposition, such as the Episkopi Formation in Hydra and the Nagyvisnyó Limestone Formation in Hungary.

Detailed clay mineralogy of the Triassic-Jurassic boundary section at Kendlbachgraben (Northern Calcareous Alps, Austria)

Abstract The Triassic-Jurassic boundary (TJB) is marked by one of the five largest Phanerozoic mass extinctions. To constrain existing models for TJB events, we obtained a stratigraphically highly resolved dataset from a marine section at Kendlbachgraben, Austria. The topmost Triassic Kössen Formation contains low to medium-charged smectite and vermiculite as alteration products of mafic-ultramafic minerals. The clay minerals in the boundary mudstone are kaolinite ≥ illite + muscovite >> smectite > chlorite. Predominant kaolinite suggests humid climate and abundant terrigenous input. In the lowermost Jurassic, the clay mineral pattern changes to illite + muscovite >> kaolinite >> smectite, which reflects change to less humid and more moderate climate. The topmost Kössen Formation also contains clay spherules. Their composition, shape and size indicate that they are alteration products of airborne volcanic glass droplets solidified in the air, settled in the sea and altered rapidly with negligible transport in terrestrial or marine environments. Our data are consistent with sudden climatic change at the TJB, as a result of large-scale volcanic activity of the Central Atlantic Magmatic Province which produced distal airfall volcanic ash.

Pyrophanite pseudomorphs after perovskite in Perkupa serpentinites (Hungary): a microtextural study and geological implications

Pyrophanite in serpentinite at Perkupa (Hungary) is described in detail for the first time as a replacement product of perovskite. It occurs as a 20- to 30-μm-wide rim, mantling a remnant core composed of perovskite or its alteration products. The pyrophanite rim consists of an inner zone, representing a pseudomorph after perovskite, and an outer overgrowth zone. Raman mapping and electron backscatter diffraction data show that the pyrophanite rims typically represent single crystals rather than being composed of multiple domains in different crystallographic orientations. Perovskite occurs exclusively in the core of pyrophanite and was identified as the orthorhombic CaTiO3 phase, based on Raman spectra. Heterogeneous, polyphase mineral cores, consisting of calcite, anatase and/or brookite, kassite, and Mn-bearing kassite, in some cases in association with relict perovskite, are typical in the larger pyrophanite-rimmed grains. The crystallographically coherent pyrophanite rims could have formed through a process where the precursor perovskite crystal acted as a structural template for the newly forming phase, that is, by interface-coupled dissolution reprecipitation during serpentinization of the precursor rock. This alteration of perovskite to pyrophanite was not complete, resulting in the presence of perovskite fragments enclosed in pyrophanite. During the metamorphic evolution of the rock, some of the remnant perovskite cores further altered to TiO2 polymorphs (anatase and brookite) and calcite, via transitional alteration products.

Medieval Gilding Technology of Historical Metal Threads Revealed by Electron Optical and Micro-Raman Spectroscopic Study of Focused Ion Beam-Milled Cross Sections

Although gilt silver threads were widely used for decorating historical textiles, their manufacturing techniques have been elusive for centuries. Contemporary written sources give only limited, sometimes ambiguous information, and detailed cross-sectional study of the microscale soft noble metal objects has been hindered by sample preparation. In this work, to give a thorough characterization of historical gilt silver threads, nano- and microscale textural, chemical, and structural data on cross sections, prepared by focused ion beam milling, were collected, using various electron-optical methods (high-resolution scanning electron microscopy (SEM), wavelength-dispersive electron probe microanalysis (EPMA), electron backscattered diffraction (EBSD) combined with energy-dispersive electron probe microanalysis (EDX), transmission electron microscopy (TEM) combined with EDX, and micro-Raman spectroscopy. The thickness of the gold coating varied between 70-400 nm. Data reveal nano- and microscale metallurgy-related, gilding-related and corrosion-related inhomogeneities in the silver base. These inhomogeneities account for the limitations of surface analysis when tracking gilding methods of historical metal threads, and explain why chemical information has to be connected to 3D texture on submicrometre scale. The geometry and chemical composition (lack of mercury, copper) of the gold/silver interface prove that the ancient gilding technology was diffusion bonding. The observed differences in the copper content of the silver base of the different thread types suggest intentional technological choice. Among the examined textiles of different ages (13th-17th centuries) and provenances narrow technological variation has been found.

Potentially Toxic Metal-Bearing Phases in Urban Dust and Suspended Particulate Matter: The Case of Budapest, Hungary

Airborne particulate matter (PM) has been widely associated with health disorders primarily due to its fine particles but also due to its toxic components (Kim et al., 2015). Recent attention has been focused on the characterisation of its very fine‐size fractions (below 10 μm) due to their easy penetration to the innermost regions of the lung (Samet et al. 2000). However, particles with a diameter up to 100 μm can be inhaled or ingested, and those below 32 μm may reach the bronchial tubes (UNEP and WHO, 1992). Airborne particulate matter can be divided into two types: the urban dust sediment and the suspended particles (Remeteiova et al., 2007). Urban dust is created by particles with great sedimentation power, and their delay time in the atmosphere is very short, causing generally near‐ source pollution. Suspended particulates, however, may travel great distances due to their small particle size, resulting in contamination far away from their sources. Both of these materials generally show significant enrichment in several potentially toxic elements in the urban environment. Thus, after sedimentation, these particles can also contaminate soils, groundwater, and even the food chain (Seiler et al., 1988). Studies on the sources, compositions, and distribution of airborne PM components are necessary for their risk assessment of atmospheric quality, ecology, and human health. This is especially true for the urban environment, where population and traffic density are relatively high, and the harmful effect of airborne PM is expected to be significantly increased (Vardoulakis et al., 2003). Environmental risk assessment of metals associated with PM has usually been based on the analysis of their total concentrations. However, it is a poor indicator of metal bioavailability, mobility, and toxicity, because these properties depend on the geochemical association of the trace elements with the different components of the solid matrix (Dabek‐Zlotorzynska et al., 2003). Unfortunately, there is no known universal analytical technique capable of identifying as well as quantifying all metal species present in airborne PM. Furthermore, owing to the chemical complexity, extremely small particle sizes, and typically small total sample sizes, such 28