Zur Deckentektonik des Hochbalkans

Zusammenfassung Im Botewgebiet der Stara Planina (Hochbalkan) liegt inmitten paläozoischer, mesozoischer und tertiärer Schichten ein 30 km langer und 12 km breiter Granitkomplex, der als autochthone Einheit, aber auch als Deckscholle gedeutet worden ist. Die Deckennatur des Komplexes wird durch die großtektonischen Verhältnisse eindeutig belegt. Der Bewegungsplan besitzt meridionale Symmetrie, die tektonischen Haupttransporte erfolgten von S nach N. Groß- und Kleingefüge entsprechen einander. Das Liegende der Decke besitzt keine einheitliche Prägung. Diskordante Lagerungsverhältnisse lassen variszische, kimmerische, kretazische, laramische und pyrenäische Bewegungen erkennen.     

A meteorological 80-m tower near Rotterdam

Construction, observation site and instrumentation are described of an 80-m meteorological observation tower, erected in Vlaardingen, The Netherlands, for studies in connection with air pollution problems along the Nieuwe Waterweg. From measurements made regularly in the period April 1967–April 1968 summaries are given of wind profile parameters and gustiness averages. Case histories are presented of an air pollution episode lasting several days, and of an hourly average wind direction difference of 120 ° over 70 m.     

Collapse structures in the Permian of the Saar-Nahe area,Southwest Germany

Volcanic breccias near an intrusive rhyolite dome in the Permian Saar-Nahe trough of southwest Germany have been identified as complex pipe-like subsidence-structures occupying the site and immediate neighbourhood of explosive volcanoes.At the Rödern, at first fine-grained, well-bedded and later coarser-grained and poorly bedded pyroclastic materials were deposited on top of a lava flow that formed the regional surface. Collapse along a ringfault with differential subsidence of 500 to 700 m produced a saucer-shaped structure in which steeply dipping pyroclastic beds still overlie the lava flow on which they were originally deposited. In the actual feeder, large blocks of country-rock subsided individually prior to wholesale subsidence of the entire feeder-content. Intrusion of a high alumina quartz tholeiite into the pyroclastic beds terminated the activity.The Hirschberg structure has essentially the same history, but is more fragmented. Subsidences vary between 150 and 260 m. Intrusion of petrographically and chemically similar basalt took place mainly near the margin of the ringfault.Three smaller structures also contain bedded pyroclastic deposits that subsided approximately 600, 1100, and 1400 m. The surface expressions of these five collapse structures are assumed to have been small collapse-calderas with diameters of several 100 m. to 1.5 km.

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Zusammenfassung Vulkanische Brekzien im Rotliegenden der Umgebung des Donnersberges in der Saar-Nahe-Senke/Pfalz liegen in Einbruchsstrukturen vor, die den ursprünglichen Schlot und seine unmittelbare Umgebung einnehmen.Am Rödern wurden ehemals auf einer Olivin-Basalt-Lava feinkörnige und spÄter grobkörnige Pyroclastica abgelagert. Einbruch an einem Ringbruch und differentielle Absenkung zwischen 500 und 700 m führte zur Anlage der trichterförmigen Struktur der geschichteten Pyroclastica. Trotz der Absenkung liegen sie immer noch mit ungestörtem Kontakt, jedoch nun steil einfallend, dem mitabgesenkten Olivin-Basalt auf.Am ursprünglichen Schlot ist Absenkung einzelner gro\er Nebengesteinsschollen und nachfolgend des gesamten Schlotinhaltes festzustellen. Die vulkanische AktivitÄt wurde durch Intrusion eines high-alumina Quarz-Tholeiites abgeschlossen.Der Hirschberg weist im wesentlichen die gleiche Struktur und Entwicklungsgeschichte auf, ist jedoch in mehrere Schollen untergliedert. Die BetrÄge der differentiellen Absenkung liegen zwischen 150 und 260 m. Infolge der Zerblockung innerhalb des Ringbruches intrudierte Basalt vorwiegend im Bereich der Verwerfungen, also am Ringbruch und zwischen einzelnen Schollen.Drei kleinere Strukturen enthalten ebenfalls geschichtete Pyroclastica und weisen maximale AbsenkungsbetrÄge von 600, 1100 und 1400 m auf.Im Bereich der ursprünglichen ErdoberflÄche müssen infolge der Einbrüche tiefe Krater vorgelegen haben, die als kleine Einbruchscalderen bezeichnet werden können.

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Résumé Aux alentours du «Donnersberg» dans la «Saar-Nahe-Senke» (Palatinat, Sudouest de l'Allemagne) des brèches volcaniques du Permien inférieur sont conservées à l'intérieur de structures d'effondrement. Celles-ci se trouvent au lieu mÊme de la cheminée originale et à ses alentours immédiats.Une de ces structures, le «Rödern», est caractérisée par des dépÔts pyroclastiques — fins à la base et plus grenus vers le sommet — couvrant des laves basaltiques à olivine. L'effondrement à l'intérieur d'une faille annulaire et une subsidence différentielle de 500 à 700 m ont eu comme résultat une structure rappelant un entonnoir. Les dépÔts pyroclastiques stratifiés reposent, quoiqu'avec un pendage fort, toujours en superposition normale et non faillés sur les basaltes à olivine qui eux aussi ont été affectés par la subsidence.A la cheminée mÊme on constate l'affaissement de grands panneaux de roches encaissantes suivi de l'effondrement de tout le remplissage de cheminée. L'activité s'achève par des venues d'une «high-alumina Quarz-Tholeiite».Le «Hirschberg», dont la structure et l'évolution ressemblent à celles du «Rödern», est caractérisé par une fragmentation du bloc effondré. L'affaissement de différents panneaux varie entre 150 et 260 m. Suite à la fragmentation de nouvelles venues basaltiques prennent place, soit le long de la faille annulaire, soit le long des failles entre les differents panneaux.Des dépÔts pyroclastiques stratifiés sont conservés encore dans trois autres structures plus petites. L'affaissement à l'intérieur de ces structures est de 600, 1100 et 1400 m au maximumQuant à la morphologie de la région après l'effondrement, on peut supposer qu'elle était caractérisée par l'existence de cratères profonds (caldères d'effondrement).

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, Donnersberg ( -, ) , . - Rödern - , . - 500–700 , . , .- , . . - Hirschberg, , , . 150–260 . , . . . - ; 600, 1100 1400 . - , , , , .

     

Eine pleistozäne Rutschung bei Kitzbühel/Tirol

ZusammenfassungEine pleistozäne Rutschung bei Kitzbühel/Tirol Bei einem Grabenaushub wurden in Grundmoräne zwei fossile Rutschkörper festgestellt. Ein Beispiel wird anhand von alten Bewegungsstrukturen beschrieben, die durch Oxydationsstreifen abgebildet wurden. Nach dem Geländeschnitt rissen z. T. die alten Schwächestellen infolge geringer Abweichungen der Scherfestigkeit des Materials wieder auf.

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SummaryA Pleistocene Landslide near Kitzbühel/Tyrol During excavation of a ditch two fossil landslides have been ascertained. One example is described the structures of which are copied by oxide bands. After excavating the old joints have opened again.

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RésuméUn glissement pléistocène près de Kitzbühel/Tyrol Pendant l'excavation d'un fossé deux glissements fossiles étaient constatés dans la moraine. Un glissement est décrit dont les structures sont illustrées par bandes d'oxydes. Les observations ont demontré que les fissures vieilles se sont ouvertes après l'excavation.

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Mit 1 Abbildung     

Electrostatic Force in Blowing Snow

Separation of electrostatic charge during the transport of particles by wind adds a force to the gravitational and fluid forces that determine trajectories of particles moving by saltation. Evaluating this electrostatic force requires the electric field strength very near the saltation surface, and charge-to-mass ratios for the moving particles. Field mill readings 4 cm above the surface in a moderate blizzard showed electric field strength as high as +30 kV m^-1. Another experiment gave charge-to-mass ratios of individual saltation particles in low-level drifting that ranged between +72 C kg^-1 and -208 C kg^-1. From these measurements, we estimated electrostatic forces as large as the gravitational force on some saltating particles. Including forces of this magnitude in the equations of motion significantly alters predicted saltation trajectories from those for uncharged particles. Predictions appear reasonable that for some saltating particles, the electrostatic force prevents new surface impacts. These results should help improve models of energy transfer in the planetary boundary layer during blizzards and sandstorms.     

Paleoenvironmental evolution of the Paratethys in the Slovenian Basin during the Late Paleogene

Several sections from the uppermost Eocene and Oligocene of northern Slovenia have been investigated with respect to sedimentary facies, foraminiferal assemblages, stable isotopes, carbonate microfacies, and palynology. The main objective was to reconstruct the paleoenvironmental history of the Paleogene Paratethys in this region of the eastern Alpine realm. The sediments exhibit a transgressive succession beginning with conglomerates, sandstones, and mudstones of fluvial and lacustrine origin followed by carbonates and muddy marls indicating marine conditions. The foraminiferal faunal changes from brackish to shallow marine to deeper marine assemblages and the distribution of the palynofloras corroborate the sedimentological results. Microfacies analysis of the limestones shows a wide variation of shallow water, generally mud-rich facies dominated by coralline algae, foraminifera, and corals. Microfaunas adapted to low-oxygen conditions indicate temporal sluggish bottom-water circulation which can be associated with high fresh-water fluxes. These results are discussed as reflecting both the global sea-level rise during the Early Oligocene and the regional tectonic and climatic evolution.     

High-resolution solar spectroscopy with TESOS – Upgrade from a double to a triple system

We present the characteristics and demonstrate the performance of the Triple Etalon SOlar Spectrometer (TESOS) operated at the German Vacuum Tower Telescope (VTT) on Tenerife. The Fabry–Pérot interferometer TESOS is ideally suited for precise measurements of photospheric and chromospheric motion. Installed in 1997 and equipped with two etalons, TESOS has recently been completed with a third etalon and upgraded with two high-speed, backside-illuminated CCD cameras. The image scale of 0.089 arc sec pixel^–1 is adapted to the resolution of the telescope. The improved system enables frame rates up to 5 frames per second. The spectral resolution of 300000 allows for spectral diagnostics of weak photospheric lines, including individual CH-lines within the G-band at 430.6 nm.     

A Reanalysis and Reinterpretation of Geodetic and Geological Evidence of Glacial-Isostatic Adjustment in the Churchill Region, Hudson Bay

We review the historical, geological, tide-gauge, GPS and gravimetric evidence advanced in favour of, or against, continuing land uplift around Hudson Bay, Canada. We also reanalyse the tide-gauge and GPS data for Churchill using longer time series than those available to previous investigators. The dependence of the mean rate of relative sea-level change obtained from the tide-gauge record on the length and mid-epoch of the observation interval considered is investigated by means of a newly developed linear-trend analysis diagram. For studying the shorter-period variability of the tide-gauge record, the wavelet transform is used. The mean rate of land uplift obtained from GPS is based on a new analysis using IGS solutions of GFZ. To include the post-glacial land uplift, sea-level indicators from the Churchill region representing the relative sea-level history during the past 8000 years are also used. Finally, the values of the four observables are jointly inverted in terms of mantle viscosity. The optimum values are ~3.2 × 10²⁰ Pa s and ~1.6 × 10²² Pa s for the upper- and lower-mantle viscosities, respectively.     

The composition of liquids coexisting with dense hydrous magnesium silicates at 11-13.5 GPa and the endpoints of the solidi in the MgO-SiO2-H2O system

High-pressure liquids in the MgO-SiO₂-H₂O (MSH) system have been investigated at 11 and 13.5 GPa and between 1000 and 1350 °C. A bulk composition more magnesian than the tie-line forsterite-H₂O was employed for the study. Rocking multi-anvil experiments were combined with a diamond trap set-up. After termination of the experiments, the liquid trapped in the diamond layer was analysed by laser ablation ICP-MS using the ‘freezing’ technique. At 11 GPa, liquids coexist with one or two of phase A, clinohumite, chondrodite, and forsterite. A marked discontinuity in the evolution of liquid compositions near 1100 °C is observed at 11 GPa. A step of ∼13 wt% H₂O and 13 wt% MgO is interpreted to result from overstepping the fluid-saturated solidus reaction mass balanced to 1.00(18) phase A + 1.07(4) fluid = 0.63(15) chondrodite + 1.44(2) melt. At 13.5 GPa liquids coexist with one or two of hydrous wadsleyite, clinohumite, superhydrous B, phase B, and forsterite. The discontinuity in liquid composition is no longer present, indicating that the second critical endpoint of the solidus has been overstepped. Thus, hydrous melts in the Mg-rich part of the MSH system (molar bulk Mg/Si > 2) are chemically distinct from aqueous fluids at pressure up to 11 GPa. Convergence of fluid and melt compositions along the solidus resulting in a supercritical liquid occurs between 11 and 13.5 GPa, at which pressure the entire MSH system becomes supercritical.