Dasycladacean alga <Emphasis Type="Italic">Palaeodasycladus</Emphasis> in the northern Tethys (West Carpathians,Poland) and its new palaeogeographic range during the Early Jurassic

The green alga Palaeodasycladus was recognized in Lower Jurassic shallow-marine high-energy calcarenites of the Cho? Nappe (Hronicum Domain) in the Tatra Mts in Poland. This occurrence indicates the most Northern record of Palaeodasycladus as it is known mostly from the southern part of the Western Tethys. The stratigraphic range of Palaeodasycladus (Norian, Sinemurian–Pliensbachian) and the upper Pliensbachian age of the overlying calcarenites (previous data on the basis of brachiopods) suggest that the studied part of the section was deposited during the Sinemurian–early Pliensbachian. The previous and current reports on occurrences of Palaeodasycladus allowed determination of a new northern palaeogeographic range of the shallow-marine Mediterranean biota during the Early Jurassic time.     

Evidence for extreme fractionation of peralkaline silicic magmas, the Boseti volcanic complex, Main Ethiopian Rift

Matrix glass and melt inclusions in phenocrysts from pantellerite lavas of the Boseti volcanic complex, Ethiopia, record extreme fractionation of peralkaline silicic magma, with Al₂O₃ contents as low as 2.3?wt.%, FeO* contents up to 17?wt.% and SiO₂ contents ~65?wt.%. The new data, and published data for natural and experimental glasses, suggest that the effective minimum composition for peralkaline silicic magmas has ~5?wt.% Al₂O₃, 13?wt.% FeO* and 66?±?2?wt.% SiO₂. The dominant fractionating assemblage is alkali feldspar?+?fayalite?+?hedenbergite?+?oxides?±?quartz. Feldspar – melt relationships indicate that the feldspar is close to the minimum on the albite-orthoclase solid solution loop through the entire crystallization history. There is petrographic, mineralogical and geochemical evidence that magma mixing may have been a common process in the Boseti rhyolites.     

Physical and chemical characteristics of after-reclamation dust from used sand moulds

The paper presents the results of investigations of physical and chemical properties of after reclamation dust that is generated in the foundry industry. Universally applied mechanical reclamation processes of spent moulding sands generate large amounts of after-reclamation dusts containing mainly rubbed spent binding agents and quartz dusts. An amount of after-reclamation dusts—in dependence of the reclamation system efficiency and the reclaim dedusting system—can reach 5–10 % in relation to the total reclaimed spent moulding sand. After-reclamation dusts originated from spent moulding sands with different kinds of resins mostly belong to dangerous wastes, since they contain chemo-setting binders with dangerous substances removed in the reclamation process. None of the companies producing mechanical reclamation systems offers presently the complex technology and equipment for utilisation of after reclamation dusts, which would meet technical and economic expectations of foundry plants. The paper presents the results of research carried out at the Faculty of Foundry Engineering AGH UST in Cracow which aims on the determination of possibilities of using the post-reclamation dust generated during mechanical reclamation of used moulding sands with organic resins as a source of energy. Different dusts generated in the mechanical reclamation process of used organic sands, delivered from foundries, were tested to determine their chemical composition, granular characterisation and physicochemical properties. As a result of the investigations, possible ways to utilise the dusts are presented.     

Housing inequalities in Bucharest: shallow changes in hesitant transition

Much has been said, yet little remains known, about the impacts of the changes associated with post-socialist transition on housing inequalities in metropolitan Central and Eastern Europe. To some extent, this depends on the scarcity of ‘hard evidence’ about the socialist epoch against which the subsequent developments may be gauged. Based on a case study of Bucharest, the Romanian capital and one of the region’s major cities, this study investigates various lines of housing inequality using data from a 20 % sample of the national censuses of 1992 and 2002. With only minor changes having taken place since the revolutionary events of late 1989, the year 1992 provides an accurate picture of the housing inequalities inherited from the socialist epoch, whereas the new societal order had largely been established by 2002. We use linear regression and binary logistic regression modeling to identify the factors that predict living space and level of facilities. The results suggest that the first decade of transition did not exert any major influences on the housing inequalities inherited from socialism, with the exception of notable improvements at the very top of the social pyramid. This finding is at odds with the literature that highlights the (suggested) effects of socio-economic polarization on the residential structure of cities after socialism. However, the results from 1992 indicate that housing was segmented along socio-economic lines already under socialism, and perhaps more so than one would have expected in the light of the literature on housing inequalities during this period.     

Coronal Mass Ejections Associated with Slow Long Duration Flares

It is well known that there is a temporal relationship between coronal mass ejections (CMEs) and associated flares. The duration of the acceleration phase is related to the duration of the rise phase of a flare. We investigate CMEs associated with slow long duration events (LDEs), i.e. flares with the long rising phase. We determined the relationships between flares and CMEs and analyzed the CME kinematics in detail. The parameters of the flares (GOES flux, duration of the rising phase) show strong correlations with the CME parameters (velocity, acceleration during main acceleration phase, and duration of the CME acceleration phase). These correlations confirm the strong relation between slow LDEs and CMEs. We also analyzed the relation between the parameters of the CMEs, i.e. a velocity, an acceleration during the main acceleration phase, a duration of the acceleration phase, and a height of a CME at the end of the acceleration phase. The CMEs associated with the slow LDEs are characterized by high velocity during the propagation phase, with the median equal to 1423 km?s^?1. In half of the analyzed cases, the main acceleration was low (a<300 m?s^?2), which suggests that the high velocity is caused by the prolonged acceleration phase (the median for the duration of the acceleration phase is equal 90 minutes). The CMEs were accelerated up to several solar radii (with the median ≈?7 R _⊙), which is much higher than in typical impulsive CMEs. Therefore, slow LDEs may potentially precede extremely strong geomagnetic storms. The analysis of slow LDEs and associated CMEs may give important information for developing more accurate space-weather forecasts, especially for extreme events.     

EPR and magnetism of the nanostructured natural carbonaceous material shungite

The X-band EPR and magnetic susceptibility in the temperature range 4.2–300 K study of the shungite-I, natural nanostructured material from the deposit of Shunga are reported. Obtained results allow us to assign the EPR signal to conduction electrons, estimate their number, N _P, and evaluate the Pauli paramagnetism contribution to shungite susceptibility. A small occupation (~5%) of the localized nonbonding π states in the zigzag edges of the open-ended graphene-like layers and/or on σ (sp ^2+x ) orbitals in the curved parts of the shungite globules has been also revealed. The observed temperature dependence of the EPR linewidth can be explained by the earlier considered interaction of conduction π electrons with local phonon modes associated with the vibration of peripheral carbon atoms of the open zigzag-type edges and with peripheral carbon atoms cross-linking different nanostructures. The relaxation time T ₂ and diffusion time T _D are found to have comparable values (2.84 × 10⁻⁸ and 1.73 × 10⁻⁸ s at 5.2 K, respectively), and similar dependence on temperature. The magnetic measurements have revealed the suppression of orbital diamagnetism due to small amount of large enough fragments of the graphene layers.     

Uplift and late orogenic deformation of the Central European Variscan belt as revealed by sediment provenance and structural record in the Carboniferous foreland basin of western Poland

The Carboniferous foreland basin of western Poland contains a coherent succession of late Viséan through Westphalian turbidites derived from a uniform group of sources located within a continental magmatic arc. Detrital zircon geochronology indicates that two main crustal components were present in the source area of Namurian A sediments. They represent Late Devonian and Early Carboniferous ages, respectively. The detritus from Westphalian D beds is much more diversified and contains admixture of Late Carboniferous zircons suggesting rapid unroofing of Variscan igneous intrusions in the hinterland between Namurian A and Westphalian D times. Tectonic repetitions of tens of metres thick fault-bounded stratigraphic intervals, recorded in several wells, provide evidence for compressional regime that occurred in the SW part of the Carboniferous basin not earlier than during the Westphalian C and produced NW–SE trending folds, concordant with the structural grain of the adjacent, NE part of the Bohemian Massif.     

Experimental metasomatism of monazite and xenotime: mineral stability, REE mobility and fluid composition

In this study a Th-bearing monazite from a Brazil beach sand, a low Th monazite from a Malawi carbonatite, and a xenotime from a pegmatite in northern Pakistan were experimentally metasomatised in a series of common metamorphic and igneous fluids at 600°C/500 MPa and 900°C/1000 MPa. Fluids included H₂O, NaCl, and KCl brines, CaF₂?+?H₂O, 1m and 2m HCl, 1m and 2m H₂SO₄, 1m NaOH, and Na₂Si₂O₅?+?H₂O. The monazite show a variety of responses to the fluids ranging from no reaction (KCl?+?H₂O) to small compositional changes and partial replacement of the monazite grain rim by Th-enriched monazite in the NaOH and (Na₂Si₂O₅?+?H₂O) experiments respectively. The other acid and brine fluids induced varying degrees of partial dissolution in the monazite and xenotime, but no compositional alteration. Partial replacement of monazite grain rims by Th-enriched monazite occurred only in the alkaline fluids as the result of a coupled dissolution-reprecipitation process.