Recreational geography in the German Democratic Republic     

Bruno Benthien 《GeoJournal》1984,9(1):59-63

This paper is a short report on concepts, methods, definitions and fields of geographical research into tourism and recreation in the GDR. Main centres of research are the Dresden College of Transport, the Dresden College of Education and the Geography sections of the Universities of Berlin and Greifswald. After the Dresden Conference on Geography of Tourism in 1965 the Greifswald Geographical Symposium on Recreational Geography in 1978 was the second decisive GDR conference. Than it became quite clear that the emphasis in research has shifted from tourism to territorial problems of recreation, primarily the various forms of outdoor recreation. The theoretical approach is shown as Greifswald model of recreational geography (Fig 1).  相似文献   

Zur inneren Tektonik des Taunus (Rheinisches Schiefergebirge) aus der Sicht der Dachschiefergrube »Rosit«     

Prof. Dr. Bruno Engels 《International Journal of Earth Sciences》1986,75(3):635-645

Zusammenfassung Detaillierte kleintektonische Untersuchungen in Querschlägen auf 5 Tiefbau-Sohlen sowie einiger Bohrkerne und übertage-Aufschlüsse lassen die Konstruktion eines entsprechend genauen Querprofils (Tafel 1) zu. Der Faltenwurf ist ziemlich disharmonisch, offenbar im wesentlichen durch zahlreiche über- und Aufschiebungen bedingt; das gleiche gilt auch für die örtlich konstruierten Faltenspiegel 1. Ordnung. Der Vergenzgrad — abzulesen an der Neigung der Faltenachsen-Flächen bzw. der Schieferung — schwankt erheblich, und zwar zwischen 0 und ± 45 NW. Harnischmylonite und andere Verquarzungen treten vor allem im Zusammenhang mit über- und Aufschiebungen auf; sie scheinen z. T. auch mitgefaltet zu sein und damit eine langfristige bzw. wiederholte Durchbewegung des »Gebirges« anzudeuten.Das Querprofil wird räumlich ergänzt durch einen Horizontalschnitt auf der 4. Sohle mit einer darin eingezeichneten Längsprofil-Serie (Tafel 2).Die offensichtlich recht komplizierte innere Tektonik der Grube »Rosit« wird sodann in Beziehung zu bekannten Strukturen des Taunus zwischen Rhein und Idsteiner Senke gebracht. Offenbar besteht über dem südlichen Mittelrhein ein tektonisches Hoch.

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Detailed local explorations of structural features (tectonic analysis) in cross-galaries of 5 underground levels, of some coredrillings and outcrops allow the construction of a corresponding detailed tectonical cross-section (Table 1). The fold structures are rather disharmonious what seems to be caused at all by numerous low-angle and high-angle reverse resp. thrust faults; this disharmony is indicated too by locally constructed fold envelopes. The degree of vergence — given by the dipping of axial planes or cleavages (vertical = 0) — differs in a considerable way from 0 to ± 45 NW. Laminated and slickensided quartz-layers and other quartz-formations seems to be connected at all with thrusts resp. reverse faults. Partly they appear ± folded what indicates a long or repeated deformation of rocks.The cross-section is completed 3-dimensionally by a horizontal section in the 4. level and by a series of longitudinal resp. striking sections (Table 2).Finally the obviously very complicated local features in the mine are brought in relations to the known structures of the Taunus between Rhine and Idsteiner Senke (depression of Idstein). It seems to exist an uplift in the southern part of the middle-Rhine.

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Résumé L'application des méthodes structurales à petite échelle dans les travers-bancs de 5 étages souterrains, ainsi que sur quelques carottes et affleurements, a permis de construire une coupe transversale assez précise (Table 1). Le plissement est relativement disharmonique, disposition qui semble causée surtout par des failles de chevauchement et des charriages; cette disharmonie apparaÎt également dans les surfaces-enveloppes des plis qui ont été construites en quelques endroits. Le degré de vergence — indiqué par la pente des plans axiaux des plis, qui correspond à la schistosité (0 = vertical) — varie dans une large mesure depuis 0 jusque ±45 vers le Nord-Ouest. Des veines de quartz à stries de glissement, ainsi que d'autres accidents quartzeux, semblent pouvoir Être mis en relation avec les failles susdites; ces veines apparaissent partiellement plissées, ce qui indique des mouvements tectoniques de longue durée, ou des mouvements répétés.En vue d'une meilleure représentation tridimensionnelle, la coupe transversale est complétée par une coupe horizontale du 4me étage souterrain accompagnée d'une série de coupes longitudinales (Table 2).Les structures à petite échelle de la mine Rosit, qui sont en fait assez compliquées, sont mises en relation avec les structures connues dans le Taunus entre le Rhin et la dépression d'Idstein. Il semble exister une surélévation tectonique dans la partie méridionale du Rhin moyen.

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Diffusion effects on oxygen isotope temperatures of slowly cooled igneous and metamorphic rocks     

Bruno J. Giletti 《Earth and Planetary Science Letters》1986,77(2)

Recently obtained data on oxygen diffusion in feldspars, quartz, and hornblende permit the prediction of the apparent¹⁸O¹⁶O temperatures that would be measured in a rock that consisted only of those three minerals, and cooled slowly from high temperature. The computed temperatures would be based on the differences in the¹⁸O¹⁶O ratios between coexisting pairs of minerals. The present calculation takes into account the diffusion rates for oxygen as a function of temperature, the cooling rate of the rock, the mineral grain sizes, and the mode of the rock. For mineral grains 1 mm in radius, and a cooling rate of 10°C/m.y., the minimum difference in apparent temperature between quartz-feldspar and feldspar-hornblende pairs will be 115°C, despite the assumption of a normal, uneventful, slow cooling history to room temperature. Further, the apparent quartz-hornblende temperature will range over 30°C (590–620°C) depending on the mode of the rock. For a cooling rate of 1000°C/m.y., the apparent difference in temperature can be as much as 400°C. Consequently, consistency in temperatures obtained by oxygen isotope analysis should not be expected in most high-grade metamorphic rocks or igneous rocks which are cooled slowly. Departures from the pattern of temperatures obtained in this model would imply a very rapid quench from high temperature, or a complex history for the rock. For some minerals, including hornblende, the relation between temperature and the equilibrium fractionation of oxygen isotopes between coexisting phases has been derived from observed relations in natural specimens. The choice of the specimens used for such calibrations needs to be re-evaluated in light of these findings. This may result in a change in the equilibrium equation constants.An example from the literature, the San Jose tonalite, Baja California, Mexico, was modelled and yieldsδ¹⁸O concentrations in the minerals that correspond closely with the measured values. This suggests that the model used is appropriate, that the rock has had a simple thermal history, and that it cooled at 100–200°C/m.y. over the temperature range 800–500°C. The set of paleotemperatures obtained for a rock will, in general, yield neither the mineral closure temperatures nor the formation or crystallization temperatures. On the other hand, the cooling rate of the rock may be derived from the data. This, in turn, may have important tectonic implications with regard to denudation and uplift rates.  相似文献   

Seasonal control of the Saint-Lawrence maximum turbidity zone by tidal-flat sedimentation     

Marc Lucotte  Bruno d’Anglejan 《Estuaries and Coasts》1986,9(2):84-94

The core of the turbidity maximum zone in the Saint-Lawrence Estuary is located in the North Channel and oscillates in front of the large (3×10⁶ m²) intertidal flats and marshes of Cap Tourmente. It is shown that seasonal fluctuations in the intensity and the position of this core are mainly determined by suspended sediment exchanges between the channel and the marshes. Fine sediments, most of them found 20 km downstream in the channel off Cap Maillard in late winter and early spring, are advected upstream over the flats during the summer months by the tide. The deposition, favored by marsh plant growth, reaches 5×10⁵ metric tons in three months. A period of intense erosion, at a mean rate of 4,500 metric tons per tide, coincides with the destruction of the plant cover by migratory geese. The material removed fills up the Chenal de l’Île d’Orléans upstream and is flushed back into the water column during the next spring freshette. This rotating seasonal sediment circulation, although very localized, exerts a major influence on the distribution and storage time of suspended particles in the upper estuary.  相似文献   

Topology in isotopic multispace and origin of mantle chemical heterogeneities   总被引：1，自引：0，他引：1  

Claude J. Allgre  Bruno Hamelin  Ariel Provost  Bernard Dupr 《Earth and Planetary Science Letters》1987,81(4)

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Primary productivity and phytoplankton size fraction dominance in a temperate North Atlantic estuary     

Stephen F. Bruno  Robert D. Staker  Gurdial M. Sharma  Jefferson T. Turner 《Estuaries and Coasts》1983,6(3):200-211

The composition, productivity, and standing crop of net (>20 μm) and nano-(<20 μm) phytoplankton of Peconic Bay, Long Island, New York was examined from June 1978 through May 1979. Nanoplankton, primarily small solitary flagellates, chlorophytes, and diatoms, dominated from May through September accounting for 88.5% of the productivity and 88.1% of the standing crop (measured as chlorophyll a). An apparent net plankton bloom began in December and continued through March. The dominant organism through most of the winter bloom was the chain-forming diatom Skeletonema costatum (Grev.) Cl. Net plankton at this time represented 66.4% of the standing crop. For both size fractions, productivity/chlorophyll a (g C per g chl a per d, integrated through the euphotic zone) was a function of light energy over the year with the exception of a few sampling dates during the post-winter bloom period. Assimilation numbers (g C per g chl a per h at saturating light intensities) were a function of temperature between 0 and 20°C. Nitrogen deficiency did not appear to be a factor in regulating phytoplankton growth rate through the euphotic zone, as ratios of ¹⁴C assimilation for dark bottles enriched with NH₃ and with no enrichment exhibited no relationship to environmental dissolved inorganic nitrogen concentrations. Zooplankton grazing pressure appeared to have been an important factor in regulating the upper limit of phytoplankton biomass and in influencing size fraction dominance. Dominance of one phytoplankton size fraction over the other on any given date was not based on physiological differences between the two groups since both fractions were composed of the same species. Apparent net phytoplankton blooms (in terms of productivity and chlorophyll a) were artifacts of increased chain lengths of nanoplankton diatoms such as Skeletonema costatum, and to a lesser extent, Thalassiosira nordenskioldii Cl. and Detonula confervacea (Cl.) Gran, rather than to the dominance of large, solitary cells.  相似文献   

The junction of Fensch and Moselle rivers,France; mineralogy and composition of river materials     

Emmanuelle Montarges-Pelletier  Laurent Jeanneau  Pierre Faure  Isabelle Bihannic  Odile Barres  Bruno S. Lartiges 《Environmental Geology》2007,53(1):85-102

The Moselle river flows in the north-east of France, from Vosges Mountains to neighboring countries Luxembourg and Germany. One of its tributaries, the Fensch river, drains a highly industrialized watershed, strongly impacted by mining, smelting and surfacing activities. The objective of this work, part of a general research program on Moselle watershed (Zone Atelier Moselle) was to assess the impact of the polluted Fensch river on the global quality of the Moselle river. For that purpose, water, sediments and suspended particulate matter were sampled in both rivers, upstream and downstream the junction. Four main sampling campaigns were carried out, in winter during a flood event and in spring at low water level. On a first step, mineralogical analyses (XRD and FTIR) and chemical analyses (ICP-MS, ICP-AES), were performed on sediments, suspended particulate matters and filtered waters. Major and trace elements concentrations were obtained on two different granulometric fractions (0–2 mm and 0–50 μm) revealing the enrichment in heavy metals of fine particles. From one collecting campaign to another, seasonal variations could be evidenced on suspended matter composition even though major minerals (calcite, quartz and kaolinite) were always present. Furthermore, spatial variations were evidenced for Fensch and Moselle downstream sediments. Thus, very fine-grained sediments, poorly crystallized, displaying at the same time higher metal concentrations and higher organic matter content than in Fensch river material, were collected downstream, in a low hydrodynamic conditions zone, assumed as a preferential sedimentary zone or even as a placer. Strong correlations could be revealed between iron content and contaminant concentrations, confirming the origin of polluted material.  相似文献   

Garnet reequilibration and growth in the eclogite facies and geodynamical evolution near peak metamorphic conditions     

Hugues Raimbourg  Bruno Goffé  Laurent Jolivet 《Contributions to Mineralogy and Petrology》2007,153(1):1-28

Caledonian eclogite-facies metamorphism partially reworking Grenvillian granulite-facies anorthosite allows us to study the processes of garnet reequilibration at high pressure and to reconstruct the evolution of the unit near metamorphic peak conditions. Our results indicate that eclogite-facies metamorphism happened in two successive phases: first, inherited granulitic garnet was fractured and reequilibrated from their boundaries (crystal or fracture rims); then eclogite-facies minerals were crystallised in the fractures as overgrowths on inherited garnets. The reequilibration of inherited garnets is achieved through Fe²⁺Mg⁻¹ exchange, whereas eclogite-facies garnets crystallised during the subsequent phase are notably richer in Ca than un- and re-equilibrated granulitic garnet. Pseudosection construction shows that this lack in Ca reequilibration cannot be related to variations in thermodynamic conditions (a _H2O, reacting system composition) between the two phases. From the compilation of the available data, the reequilibration of granulitic garnet seems to be controlled by the inefficient intra- and inter-granular transport properties of Ca compared to Fe²⁺ and Mg. While these kinetic factors confine garnet reequilibration to Fe²⁺Mg⁻¹ exchange, the extent of reequilibration along this exchange vector is controlled by partitioning with adjacent omphacite. On the contrary to the diffusional reequilibration of granulitic garnet that lasted for several My according to our modelling of the diffusional relaxation, the strong compositional gradients between eclogite-facies and reequilibrated garnets, which are almost unaffected by diffusional reequilibration, provide evidence that rapid exhumation followed the crystallisation of eclogite-facies minerals. We propose that the movement reversal itself, from burial to exhumation, and associated deformation and fluid flow, triggered this crystallisation event. The resulting evolution near metamorphic peak conditions is therefore strongly asymmetrical: on the one hand, the prograde diffusional relaxation profiles indicate slow movement during the last stages of burial, whereas the unaffected retrograde overgrowth indicates fast exhumation rates.  相似文献   

EFFECTS OF RIVER NETWORK WORKS AND SOIL CONSERVATION MEASURES ON RESERVOIR SILTATION     

Bruno MOLINO Rosa VIPARELLI Annamaria DE VINCENZO 《国际泥沙研究》2007,22(4):273-281

Knowledge of the morphological dynamics of a water course is essential for management of reservoir siltation. With an example of sedimentation in a reservoir in Basilicata, Italy, this paper demonstrates the effect on reservoir siltation of the hydraulic works, which are aimed to reduce sediment transport along the fluvial network and to prevent part of the sediment discharge from reaching the lake. The effect depends on the river type and on the the geological features of river basin slopes. The paper also shows how mass erosion can significantly contribute to development of reservoir siltation. Finally, preliminary results are provided about the time needed for river training works to be effective.  相似文献   

Cancellation exponents and multifractal scaling laws in the solar wind magnetohydrodynamic turbulence   总被引：1，自引：0，他引：1  

V. Carbone  R. Bruno 《Annales Geophysicae》1996,14(8):777-785

Some signed measures in turbulence are found to be sign-singular, that is their sign reverses continuously on arbitrary finer scales with a reduction of the cancellation between positive and negative contributions. The strength of the singularity is characterized by a scaling exponent , the cancellation exponent. In the present study by using some turbulent samples of the velocity field obtained from spacecraft measurements in the interplanetary medium, we show that sign-singularity is present everywhere in low-frequency turbulent samples. The cancellation exponent can be related to the characteristic scaling laws of turbulence. Differences in the values of , calculated in both high- and low-speed streams, allow us to outline some physical differences in the samples with different velocities.  相似文献