Income distribution dynamics and cross-region convergence in Europe

This paper presents a continuous version of the model of distribution dynamics to analyse the transition dynamics and implied long-run behaviour of the EU-27 NUTS-2 regions over the period 1995–2003. It departs from previous research in two respects: first, by introducing kernel estimation and three-dimensional stacked conditional density plots as well as highest density regions plots for the visualisation of the transition function, based on Hyndman et al. (J Comput Graph Stat 5(4):315–336, 1996), and second, by combining Getis’ spatial filtering view with kernel estimation to explicitly account for the spatial dimension of the growth process. The results of the analysis indicate a very slow catching-up of the poorest regions with the richer ones, a process of shifting away of a small group of very rich regions, and highlight the importance of geography in understanding regional income distribution dynamics.

New age constraints on emplacement of the Cévenol granitoids, South French Massif Central

During the development of the Variscan orogeny, large amounts of granitic melt were produced, giving rise to the intrusion of granitoids at different structural levels. Despite numerous studies, ages available from previous work on the Cévennes granites remain largely imprecise. In order to better constrain the age and emplacement mode of these granites, we have combined U–Pb dating on monazites and zircons and ⁴⁰Ar/³⁹Ar dating on biotites with petrological observations, major element chemical analysis and SEM zircon imaging on five samples from the Aigoual–St Guiral–Liron and Mont Lozère granitic massifs. The results revealed that granitic intrusions and cooling in Southern Cévennes occurred in a short time span at ∼306 Ma after the main episode of regional metamorphism. Petrological and chemical data suggest that they result from a mixing between mantle-derived basic magmas (lamprophyres) and lower crust acid magmas. At a regional scale the production of these melts occurred at the end of crustal thickening induced by nappe stacking, at the same time as the late anatectic events recorded further north in the Velay dome and the granulite facies metamorphism recorded in metasedimentary granulite enclaves brought up by Tertiary volcanoes of the Velay area (Bournac).     

Composition and pre-metamorphic geodynamic setting of the ultrahigh-pressure metabasic rocks from Dabie Shan,E-China

As part of the Yangtze plate, segments of the Dabie Shan terrane of Central China underwent ultra-high pressure metamorphism during Triassic subduction. We studied the geochemistry of the abundant eclogites to evaluate the nature of the protoliths and their geodynamic setting. Although some previous geochemical work exists, the analyses and interpretation herein are based on a new subdivision of the ultra-high pressure sequence into basement and cover units (Changpu and Ganghe Unit), revealing new and important results. In addition, eclogites of the so-called HP Unit south of the UHP units were studied. Whereas the large ion lithophile elements indicate postmagmatic, metasomatic changes of some samples, the high-field strength elements and the rare earth elements display original magmatic trends. The geochemical characteristics of the eclogites of the ultra-high pressure areas display a strong dependence on their “structural” and geographic position. The eclogites of the basement and the Changpu Unit indicate melt intrusion and extrusion in a continental rift system, i.e. during extensional tectonics. In contrast, the Ganghe Unit is characterized by a pronounced chemical homogeneity. The composition of the eclogites indicates generation from a mantle source highly influenced by slab-derived fluids. Those of the HP Unit show similar characteristics. Magmatism of the Ganghe and HP Unit probably occurred in a continental arc setting. A similar age for both units, geographically and/or tectonically separated, is possible. The geodynamic interpretation based on the geochemistry of the four units points to a Neoproterozoic scenario in which the protoliths of the HP and the cover units could have been of similar age and deposited in one evolving geological system. A rift-related larger-scale basin might have formed, e.g. a continental back-arc basin behind a magmatic arc after or simultaneous to sedimentation and magmatism in the magmatic arc. Alternatively, magmatism occurred in independent geodynamic settings, distinct in time and space. The units were juxtaposed during exhumation, after subduction to varying depths.     

Zircon M257 ‐ a Homogeneous Natural Reference Material for the Ion Microprobe U‐Pb Analysis of Zircon

We introduce and propose zircon M257 as a future reference material for the determination of zircon U‐Pb ages by means of secondary ion mass spectrometry. This light brownish, flawless, cut gemstone specimen from Sri Lanka weighed 5.14 g (25.7 carats). Zircon M257 has TIMS‐determined, mean isotopic ratios (2s uncertainties) of 0.09100 ± 0.00003 for ²⁰⁶pb/²³⁸U and 0.7392 ± 0.0003 for ²⁰⁷pb/²³⁵U. Its ²⁰⁶pb/²³⁸U age is 561.3 ± 0.3 Ma (unweighted mean, uncertainty quoted at the 95% confidence level); the U‐Pb system is concordant within uncertainty of decay constants. Zircon M257 contains ～ 840 μg g^?1 U (Th/U ～ 0.27). The material exhibits remarkably low heterogeneity, with a virtual absence of any internal textures even in cathodoluminescence images. The uniform, moderate degree of radiation damage (estimated from the expansion of unit‐cell parameters, broadening of Raman spectral parameters and density) corresponds well, within the “Sri Lankan trends”, with actinide concentrations, U‐Pb age, and the calculated alpha fluence of 1.66 × 10¹⁸ g^?1. This, and a (U+Th)/He age of 419 ± 9 Ma (2s), enables us to exclude any unusual thermal history or heat treatment, which could potentially have affected the retention of radiogenic Pb. The oxygen isotope ratio of this zircon is 13.9%o VSMOW suggesting a metamorphic genesis in a marble or calc‐silicate skarn.     

Particle size distribution and dissolution properties of metals in cyclone fly ash

The particles in the examined cyclone fly ash were all smaller than 0.25 mm. in diameter, and particles smaller than 0.075 mm. in diameter accounted for 88.4 % of the ash weight. This result indicates that cyclone fly ash consists of particles with a small diameter. The metals in the cyclone fly ash were enriched in small particles. The highest concentrations for zinc, copper, lead, cadmium and molybdenum in the cyclone fly ash were found in the smallest particle size fraction (< 0.075 mm.) and for Barium, chromium, nickel, Vanadium and Cobalt in the second to smallest particle size fraction (0.075-0.125 mm.). From an environmental and toxicological standpoint, the smallest particles are of the greatest concern when ash is handed at landfill disposal sites (transport and disposal especially in stormy weather conditions), and some studies have reported risks to workers from prolonged exposure to ash. The results of the comparison of various dissolution methods for metals showed that the digestion procedures with nitric acid alone (USEPA 3051) or with a mixture of nitric acid + hydrogen peroxide (USEPA 3050B) slightly underestimated the metal concentrations in the cyclone fly ash. Although the use of hydrofluoric acid is often necessary for the determination of a number of elements associated with siliceous minerals, its use can result in loss of trace elements during dissolution.     

The qualitative zoning record of minerals. A method for determining the duration of metamorphic events?

Summary The efficacy of ion exchange in petrological systems, for example the Fe-Mg exchange between garnet and biotite, is a function of grainsize, temperature, rates of temperature change and diffusion parameters. The combination of these variables determines the final zoning profile of minerals. Therefore, zoning profiles may be used to derive one of these variables if the others are known. For example, a mineral grain that experienced a short thermal event may still preserve a zoning profile characteristic of the heating path. In contrast, if that grain experienced a long thermal event it may develop a zoning profile typical of the cooling path. Conversely, for the same temperature-time cycle, large grains may not completely equilibrate at the metamorphic peak, and in smaller grains any previous record may have been erased. This is commonly observed in natural rocks where different grains within one thin section preserve often qualitatively different zoning profiles. Thus, a critical grainsize,l _crit, may exist that separates grains with qualitatively different zoning profiles so that grains of sizel > l _crit still retain zoning information about the heating path and grains of sizel <l _crit contain only information about the cooling path. If the critical grainsize can be measured and an independent estimate for the peak metamorphic temperature exists, the duration of the thermal event may, in principle, be estimated.The applicability of this method to natural garnets is hampered by a range of uncertainties. However, a parameterisation of the critical grain size may be used to illustrate the relative importance of grain size, temperature and event duration to the equilibration of minerals. In this paper, the critical grainsize is parameterized for various temperature-time cycles and its dependence on diffusion parameters is discussed. It is shown that, for Barrovian conditions,l _crit between 0.1 and 1 mm separates garnets retaining prograde information from garnets retaining cooling path information. For illustration, we compare the results with the critical grainsize of garnets from two metamorphic terranes, the Prydz Bay region (Antarctica) and the Koralm complex (Eastern Alps). Despite the large range of uncertainties attached to the method, it is shown that the critical grainsize of garnets in both terranes is consistent with a very short duration of the last thermal event that affected the two regions.

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Die qualitative Form von Zonierungsprofilen in Mineralen. Information über die Dauer metamorpher Ereignisse?

Zusammenfassung Zonierungsprofile von Paragenesen im Ionenaustausch, zum Beispiel das Fe-Mg Austauschsgleichgewicht zwischen Granat und Biotit, sind eine Funktion von (i) Korngröße, (ii) Temperatur, (iii) Kühl- und Heizgeschwindigkeit sowie (iv) den Diffusionskonstanen. Es sollte daher möglich sein, Zonierungsprofile dazu zu verwenden, einen dieser Parameter zu bestimmen, wenn die anderen bekannt sind. Zonierungsprofile von Kristallen die ein kurzes thermisches Ereignis erfahren haben, mögen daher prograde Information beinhalten, wogegen derselbe Kristall ein retrogrades Profil aufweisen mag, wenn er einem langlebigen thermischen Ereignis unterlag (prograd und retrograd ist hier als: bei ansteigender Temperatur und bei abfallender Temperatur definiert). In Kristallen die dem gleichen Temperatur-Zeitpfad unterworfen waren, könnten kleine Körner nur die Kühlgeschichte dokumentieren, wogegen große noch Zonierungsinformation vom Heizpfad aufweisen. In natürlichen Gesteinen wird das oft dadurch beobachtet, daß verschiedene Körner auseinem Dünnschliff qualitativ verschiedene Zonierungsprofile aufweisen. Es ist daher möglich eine kritische Korngöße,l _crit, zu definieren, die Korngrößen mit qualitativ verschiedenen Zonierungsprofilen voneinander trennt. Körner mit einem Durchmesserl > l _crit haben, zumindest teilweise, noch prograde Profile, wogegen Körner mitl <l _crit nur retrograde Information dokumentieren. Wenn man diese kritische Korngröße messen kann, sollte sie dazu benutzt werden können, etwas über die Dauer des thermischen Ereignisses auszusagen.Die Anwendbarkeit dieser Methode ist durch eine Reihe von Fehlern limitiert. Nichtsdestotrotz, ist eine Parameterisierung der kritischen Korngröße nützlich um die relative Wichtigkeit von Korngröße, Temperatur und Zeit, für die Entwicklung von Zonierungsprofilen, zu illustrieren. Unser Modell kann dazu benutzt werden, um die Größenordnung von Granaten abzuschätzen, die noch prograde Information dokumentieren können. Die Abhängigkeit der kritischen Korngröße von Diffusionsparametern und der Form des Temperatur-Zeit Pfades wird ebenfalls diskutiert. Es wird gezeigt, daß für Metamorphose in der mittleren Grünschiefer und Amphibolit fazies,l _crit zwischen 0.1 and 1 mm prograd zonierte von retrograd zonierten Granaten trennt. Um das Modell zu illustrieren, werden die Ergebnisse auf die Prydz Bay Region (Antarktis) und den Koralm Komplex (Ostalpen) angewendet. Trotz der großen Fehlergrenzen der Methode glauben wir zeigen zu können, daß die kritische Korngröße beider Terrains andeutet, daß das letzte thermische Ereignis in beiden Gebieten kurzlebig war.

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With 5 Figures