Die Wurzel der Osning-Überschiebung und der Mechanismus herzynischer Inversionsstörungen in Mitteleuropa

Zusammenfassung Neuere Untersuchungen ergaben, daß die Osning-Überschiebung als flache Störung in der steilen südlichen Randverwerfung der Ibbenbürener Karbonscholle wurzelt. Die Karbonscholle selbst ist von fiedrig angeordneten Randbrüchen begrenzt, die offenbar Teil eines varistischen Osning-Lineamentes sind. Das tektonische Inventar der Karbonscholle und die Osning-Überschiebung im Deckgebirge des südlichen Vorlandes werden als Folge einer Einengung und Heraushebung der Scholle in der Oberkreide gesehen, wobei die fiedrige Anordnung der Randstörungen eine Umsetzung horizontaler Seitenverschiebungen in Vertikalbewegungen bewirkte. Es wird angenommen, daß die Osning-Überschiebung generell in einem steilen Tiefenbruch wurzelt. Die Osning-Zone und andere herzynisch streichende Bruchsysteme mit daran gebundenen Falten und Überschiebungen dürften ihre Ursache in konvergierenden Schollenbewegungen mit horizontalen Seitenverschiebungen haben.

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Recent investigations revealed that the Osning thrust originates as a low angle plane in the southern marginal fault of the Ibbenbüren Carboniferous block. The fault block itself is limited by steep faults, which are considered to be en echelon faults as part of the variscan Osning lineament.The structures of the fault block indicate a compression and uplift of the Ibbenbüren fault block by strike-slip movements at the en echelon Osning lineament. In connection with the uplift compressional and lateral shearing movements produced the south vergent Osning thrust within the overlaying strata. Thus, it is concluded, that the flat Osning thrust in their total extension originates in steep faults. It is further presumed that Osning Zone as well as other NW-SE striking fault systems connected with folds and thrusts in Middle Europe are caused by transpression.

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Résumé Des études récentes amènent à regarder le charriage de l'Osning comme un accident faiblement incliné qui s'enracine dans la faille redressée formant la bordure sud du bloc carbonifère d'Ibbenbüren. Le bloc carbonifère est lui-même limité par des failles marginales en échelons, considérées comme faisant partie du linéament hercynien de l'Osning. L'inventaire tectonique du bloc carbonifère et le charriage de l'Osning dans la couverture de l'avant-pays méridional sont interprétés comme les effets d'un raccourcissement et d'une montée du bloc pendant le Crétacé supérieur, la configuration des failles marginales en échelons étant responsable de la transformation des déplacements horizontaux en mouvements verticaux. On conclut que le charriage de l'Osning, dans son ensemble, s'enracine dans une fracture profonde à fort pendage. La zone de l'Osning ainsi que d'autres zones failleuses WNW-ESE d'Europe Centrale avec les plis et les charriages qui leur sont associés sont considérés comme le résultat de mouvements convergents de blocs liés à des décrochements.

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Geomorphological findings on the build-up of pleistocene glaciation in Southern Tibet and on the problem of inland ice —

Summary The last Ice Age (Würm) glacier cover was reconstructed on the basis of standard geomorphological indicators in S Tibet between the S slope and N slope of the Himalaya by way of the Tibetan Himalaya to the Transhimalaya (28° – 29° 50' N/85° 40' – 91° 10' E). At the same time, though subject to varying density of data, the process of Late and Post-Glacial deglaciation to Neo-Galacial and Recent glacier cover was considered. Evidence of an almost total glaciation of S Tibet was found in indicators like glaciated knobs, trough valleys with pronounced flank polishings and limits of glacial scouring on nunataks, as well as in findings of erratics, lateral moraines, end moraines, and terraces of outwash plains. This total glaciation took the form of an ice-stream network and attained a thickness of at least 1200 m. Ice-free to about 87° – 86° E, the Tsangpo valley with its sander deposits occupied the gap between the glacier areas of the Tibetan and High Himalayas in the S (I 3) and those of the Transhimalaya in the N (I 2). In the light of recently glaciated Late Glacial terminal moraines and ice marginal rapms it has been possible to estimate a glacio-isostatic uplift of c. 400 m during 10 x 10³ years (an average of 40 mm/year) following deglaciation. It is about 3 to 8 times greater than the tectonic uplift of the High Himalaya. The post-glacially intensified uplift of the S Tibetan Plateau by comparison with the High Himalaya is attributed to the much greater glacier burden during the Ice Age.In the area under investigation a High Glacial ELA depression (equilibrium line altitude depr.) of at least 1200 (1180) m was reconstructed for a mean altitude of about 4700 (4716) m asl. Assuming constant hygric conditions and a gradient of 0.7° C/100 m, the temperature drop at the time would have been 8.4° C. Since precipitation during the Ice Age must, if anything, have been less, a drop in summer temperature of about 10° C may be regarded as probable.     

Decollements in slate belts,examples from the European variscides and the Qin Ling Belt of Central China

Decollements are conspicuous features of collision belts as a result of shortening and shearing of rocks of different competencies in response to intracontinental subduction and crustal stacking. When these decollements occur at upper levels, the classical thin skin tectonics of the foredeeps without important internal strain results; at mid crustal levels slaty cleavage and foliation development occurs. In the more internal parts of the chains, in the lower crust, near the crust mantle boundary, the more severe conditions (granulitic metamorphism) result in ductile deformation in the deepest parts of the mountain belts. Examples of middle and lower crust are well documented in Central China and the Variscan Belt of Europe from field evidence and deep seismic profiling.From these examples it appears more and more likely that most of the mid-crustal slate belts showing vertical slaty cleavage at the erosion surface overly flat decollements.At greater depth large decollements must occur as well in the lower continental crust and at crust-mantle boundary. Typical features of the deep seismic vertical profiles such as the strongly layered lower crust may represent the image of such deep decollements.

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Zusammenfassung Abscherungen sind charakteristische Strukturen von Kollisions-Orogenen. Sie sind das Ergebnis von Verkürzung und Scherung verschieden kompetenter Gesteine infolge intrakontinentaler Subduktion und Krustenüberlagerung. Zu unterscheiden sind Überschiebungen oberer Zonen, wie in den Randgebirgsbereichen ohne bedeutende innere Deformation, von internen metamorphen Zonen mit Schieferung und Plättung. In den tiefen Krustenzonen und im Krusten-Mantelbereich gehen sie einher mit hochgradiger Metamorphose, allgemein in der Granulitfazies.Beispiele der mittleren und tiefen Zonen sind gut erschlossen im paleozoischen Orogen Zentralchinas und im Variszikum Europas und belegt sowohl durch die Geologie wie tiefenseismische Profile. Diese Beispiele zeigen mehr und mehr, daß geschieferte Gebirgsstockwerke mit an der Oberfläche steilstehender Schieferung von flachen Abscherungen unterlagert werden.Die typische Erscheinung einer seismisch gut geschichteten Strukturierung der Unterkruste könnte in dieser Hinsicht als Deckenbahnen interpretiert werden.

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Résumé Les décollements sont des structures typiques des chaînes de collision. Ils résultent du raccourcissement et du cisaillement de roches de différentes compétences en réponse à la subduction continentale et à l'empilement crustal. On peut distinguer des décollements superficiels surtout dans les bassins d'avant chaîne où les roches charriées ont subi une déformation interne faible à nulle (plis et chevauchements sans schistosité). Des décollements plus profonds dans le tiers supérieur de la croûte accompagnés de schistosité et de foliation, dans les parties plus internes métamorphiques des chaînes. Enfin des décollements très profonds à la base de la croûte ou entre croûte et manteau, accompagnés ou suivis d'un métamorphisme de haut degré, généralement granulitique.Ces deux derniers types de décollement sont clairement exprimés dans la chaîne Varisque d'Europe et dans la chaîne Paléozoïque Qin Ling de Chine Centrale. Il apparaît ainsi de plus en plus évident que la plupart des zones plissées à schistosité verticale, non liées à des décrochements, passent en profondeur à de grands décollements plats. On les met en évidence sur le terrain ou/et grâce à des profils de sismique réflexion écoute longue. Des aspects caractéristiques de ces profils comme par exemple la croûte inférieure litée pourraient représenter l'image sismique de tels décollements profonds.

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Land classification of part of Thrace (East Rhodope) by visual interpretation of MSS images of first and second generation landsat images

The aim of this investigation was the classification of East Rhodope mountain ridge area and the surrounding hills and plains into mapping units by visual interpretation of 1:500,000 paper print enlargements of MSS false colour composites (bands 1, 2 and 4) of LANDSAT-4 and MSS (band 7) of LANDSAT-1, supported by limited field observation and background information available from earlier surveys and maps. The basic mapping units used in the present study was the land systems (developed by CSIRO in Australia) because they are easily recognizable on LANDSAT images by their destinctive combination of physiography, soils and vegetation.The twenty various land systems occurring in the study area, such as high/low mountains with smooth/sharp summits, nearly flat/undulated plains, slightly/strongly dissected hilles etc., were defined and mapped on small scale of 1:500,000. They are of considerable interest because they provide the framework for production of the same scale geological and geo-morphological maps, erosion studies, soil, vegetation and other thematic mapping for natural resources surveys, because LANDSAT images reveal details of terrain and microrelief that can never be reproduced on a topographic map. Also this land system map may modify or add to earlier small scale thematic maps (geology, soils and vegetation/forestry maps) produced in the past by other techniques.     

Demographic,economic, socio-cultural and political facts nowadays in the French Pacific territories

Demographic, sociocultural, economic, and political trends in the French islands of the South Pacific are examined. Consideration is given to population distribution, internal and interisland migration, economical assets and weaknesses, political relationship with France, and cultural traditions unique to New Caledonia, French Polynesia, and Wallis and Futuna Islands.     

The crystal structure of nabokoite,Cu7TeO4(SO4)5 · KCl: The first example of a Te(IV)O4 pyramid with exactly tetragonal symmetry

Summary The crystal structure of the tetragonal fumarole mineral nabokoite, Cu₇TeO₄(SO₄)₅ · KCl (a=9.833 (1).Å,c=20.591(2) Å, space groupP 4/ncc, Z=4) was determined by single crystal X-ray methods on type material from Kamchatka. The structure contains complicated {[CU₇TeO₄(SO₄)₄]SO₄} sheets that are intercalated by K and Cl ions. Nabokoite presents the first example of a Te(IV)O₄ pyramid with exactly tetragonal symmetry. The K ions have a somewhat unusual, rather flat coordination.

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Die Kristallstruktur des Nabokoits, Cu₇TeO₄(SO₄)₅ · KCl: Das erste Beispiel für eine Te(IV)O₄-Pyramide mit exakt tetragonaler Symmetrie

Zusammenfassung Die Kristallstruktur des tetragonalen Fumarolenminerals Nabokoit, Cu₇TeO₄(SO₄)₅ · KCl (a=9,833(1)Å,c=20,591(2)Å, RaumgruppeP 4/ncc, Z=4) wurde an Typ-Material von Kamtschatka mit Röntgen-Einkristallmethoden bestimmt. Die Struktur enthält komplizierte [Cu₇TeO₄(SO₄)₄]SO₄-Schichten, die durch K- und Cl-Ionen verbunden werden. Nabokoit liefert das erste Beispiel für eine Te(IV)O₄-Pyramide mit exakt tetragonaler Symmetrie. Die K-Ionen haben eine etwas ungewöhnliche, ziemlich flache Koordination.

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With 2 Figures     

On atmospheric vortex streets in the wake of large islands

Summary Results from laboratory experiments on stably stratified flows over three-dimensional obstacles are related to atmospheric vortex streets formed in the lee of large islands. A quasi horizontal flow around the island can be expected if stable stratification favours the formation of a so-called dividing streamline below the islands top. The subsequent shedding of vortices with vertical axis from islands may then be due to viscous boundary layer separation, but also other possible mechanisms of vortex shedding in stably stratified flows are discussed.With 6 Figures     

Reedbed Treatment of Sewage in the UK

Natural wetlands perform significant sewage treatment, but artificial reedbeds are likely to be more reliable and effective. The processes responsible for purification in wetlands and reedbeds are described in this paper, together with an outline of the experimental reedbeds which have been established in the UK up to 1987. Major research needs are outlined.     

Ionenaustausch mit zeolithischen Molekularsieben unter dem besonderen Aspekt der Wasserenthärtung – Eine Einführung

After a short introduction into the field of the zeolites the use of the molecular sieve 4 A as builder in the washing process is treated. Structure and ion-exchange capacity are characterized, the mechanism of the elimination of calcium-ions is described and the environmental behaviour is examined. Finally, other potential applications of zeolitic ion exchangers are presented.