Le Capelinhos (Faïal,Açores) vingt ans après son éruption: le modèle éruptif «surtseyen» et les anneaux de tufs hyaloclastiques

Phreatomagmatic structures are of two kinds: maars and tuff-rings. Data given by records of Capelinhos activity (Faïal, Açores, 1957–1958), by structures at west point of Faïal island, and by palagonitic breccias of Velay and Cantal areas (France) lead to relate hyaloclastic tuff-rings and shallow subaquatic («surtseyan») eruptions. It is possible to precise causes, characteristics, and mechanism of formation of tuff-rings.     

Mortar Upscaling for Multiphase Flow in Porous Media

In mortar space upscaling methods, a reservoir is decomposed into a series of subdomains (blocks) in which independently constructed numerical grids and possibly different physical models and discretization techniques can be employed in each block. Physically meaningful matching conditions are imposed on block interfaces in a numerically stable and accurate way using mortar finite element spaces. Coarse mortar grids and fine subdomain grids provide two-scale approximations. In the resulting effective solution flow is computed in subdomains on the fine scale while fluxes are matched on the coarse scale. In addition the flexibility to vary adaptively the number of interface degrees of freedom leads to more accurate multiscale approximations. This methodology has been implemented in the Center for Subsurface Modeling's multiphysics multiblock simulator IPARS (Integrated Parallel Accurate reservoir Simulator). Computational experiments demonstrate that this approach is scalable in parallel and it can be applied to non-matching grids across the interface, multinumerics and multiphysics models, and mortar adaptivity. Moreover unlike most upscaling approaches the underlying systems can be treated fully implicitly.     

The Tepla(?)/Saxothuringian suture in the Karkonosze–Izera massif, western Sudetes, central European Variscides

The southern and eastern Karkonosze-Izera massif (northern Bohemian Massif) exposes blueschist facies rocks and MORB-type magmatic complexes. During Late Devonian to Early Carboniferous times, these were overthrust within a nappe pile toward the NW onto the pre-Variscan Saxothuringian basement composed of the Izera-Kowary metagranitoids and their envelope. The lowermost nappe (or parautochthonous?) unit of the pile is the low-grade metamorphosed Jewt3d complex, comprising a Devonian to Early Carboniferous sedimentary succession of the Saxothuringian passive margin. This is tectonically overlain by the South Karkonosze complex, which represents Ordovician-Silurian volcano-sedimentary infill of the Saxothuringian basin, affected by Late Devonian HP metamorphism. The uppermost nappe is the Early Palaeozoic epidote-amphibolite grade Leszczyniec MORB-like complex, cropping out on the eastern margin of the Karkonosze-Izera massif. It probably represents a fragment of obducted Saxothuringian basin floor. The nappe pile was stacked beneath the overriding upper plate margin, now concealed below the Intra-Sudetic basin and hypothesized to represent a fragment of the Tepla-Barrandian terrane. The nappe stacking, triggered by buoyancy-controlled upward extrusion of the subducted continental slab, was the main mechanism for the exhumation of HP rocks. The final stages of the NW-ward nappe stacking were accompanied and followed by SE-directed Early Carboniferous extensional collapse. The lower plate of the suture zone was uplifted at that time and intruded by the ~330-Ma-old, nearly undeformed Karkonosze granite pluton. As a result of the collapse, the Tepla-Barrandian(?) upper plate was downthrown on shear zones and brittle faults and buried under several km-thick synorogenic Late Tournaisian(?) through Namurian and post-orogenic Late Carboniferous-Early Permian succession of the Intra-Sudetic basin. The south and east Karkonosze suture most probably is a fragment of the Tepla/Saxothuringian (Münchberg-Tepla) suture belt known from the western Bohemian Massif.     

On the energy gap for Fe-poor oxide and silicate minerals

A relationship between the energy gap (E _G) and the density (ρ) over mean atomic weight (〈A〉) ratio for Fe-poor oxide and silicate minerals is derived from simple properties of their free atom-components. Theoretical considerations are based on the Lorentz electron theory of solids. The eigenfrequency ν ₀ of elementary electron oscillators, in energy units h ν ₀, is identified with the energy gap of a solid. The numerical relation is of the form $$(\langle U_0 \rangle ^2 - E_G^2 )\frac{{\langle A\rangle }}{\rho } = \frac{4}{3}\pi \hbar ^2 \frac{{e^2 }}{m}N = 276.79 eV^2 cm^3 /mol$$ where 〈U ₀〉 is the average first ionization potential (per free atom), ? is crossed Planck's constant, e is the electron charge, m is the electron rest mass, and N is Avogadro's number. For several geophysically interesting oxide and silicate minerals which are in general composed of four different elements (O, Si, Mg and Al), we obtain from laboratory data that the mean value of $$\left\langle {[\langle U_0 \rangle ^2 - (E_G^{lab} )^2 ]\frac{{\langle A\rangle }}{\rho }} \right\rangle \approx 248.2 \pm 20.9eV^2 cm^3 /mol.$$ .     

Normal form,Lie-Poisson structure and reduction for the Henon-Heiles system

The reduced Henon-Heiles system is investigated as a Hamiltonian dynamical system obtained by applying the normalization of the HamiltonianH=1/2(p ₁ ² +p ₂ ² +q ₁ ² +q ₂ ² )+1/3q ₁ ³ –q ₁ q ₂ ² to fourth-degree terms. The related equations of motion are bi-Hamiltonian and possess the Lie-Poisson structure. Each Lie-Poisson structure possesses an associated Casimir function. When reduced to level sets of these functions, the equations of motion take various symplectic forms. The various reductions give different coordinate representations of the solutions. These coordinate representations are used to seek the simplest representation of the solutions.     

Neuere Ergebnisse der Anwendung physikalischchemischer Methoden auf Probleme der Geologie

Ohne Zusammenfassung     

Effects of rainy season on mobilization of contaminants from tsunami deposits left in a coastal zone of Thailand by the 26 December 2004 tsunami

Study on contamination of tsunami sediments deposited on 26 December 2004 conducted shortly after the tsunami in coastal zone of Thailand revealed elevated contents of salts in water-soluble and some heavy metals and arsenic in bioavailable fractions (Szczuciński et al. in Env Geol 49:321–331, 2005). Few months later rainy season started and effected in total rainfall of over 3,300 mm. This paper presents results of survey repeated 1 year after the tsunami. To assess the effects of rainy season on mobilization of previously determined potential contaminants, the same locations were sampled again and analysed with the same methods. The tsunami deposit layer was well preserved but in many locations the sediments were coarser than just after tsunami due to washing out of finer fractions. The water-soluble salts contents were strongly reduced after the rainy season. However, the concentrations of acid leachable heavy metals and metalloids were still elevated in comparison to reference sample from an area not impacted by tsunami. It is possible that the metals and metalloids are successively moved to more bioavailable fraction from forms which were more resistant to mobilization.     

Archaeological objects in loesses recognized by GPR research at the site Karmanowice,Poland

The aim of the research was to examine subsurface soil layers with the use of the Ground Penetrating Radar (GPR) method. Neolithic archaeological post in Karmanowice was examined. On the basis of earlier geophysical researches and archaeological premises, eight measurement profiles had been chosen. Ground Penetrating Radar system with antenna of 500 MHz frequency was applied. The measurements were made with 30 and 60 ns time windows. The results were shown as the GPR sections. The analysis of the obtained results allowed us to outline anomalies connected with the appearance of archaeological objects in subsurface soil layers. The border between the anthropogenically changed upper layer and undisturbed loess was established, and the sections of slope wash layers were designated. Anomalies were confirmed by digging and test drillings. Additionally, 2D resistivity imaging method was used for verification of specific anthropogenic anomalies.