Die Kupfervererzung vom Gaskasjavri in Troms (Norwegen)     

Werner Tufar 《Mineralogy and Petrology》1967,12(1):61-99

Zusammenfassung Aus den nordnorwegischen Kaledoniden wird ein neues Kiesvorkommen vom Gaskasjavri in der Provinz Troms beschrieben, das sich durch Gangarten auszeichnet, die unter stärkeren Metamorphosebedingungen gebildet wurden und die Mineralisation skarnähnlich erscheinen lassen. Die hochtemperiert angelegte Vererzung wird von Magnetit und einigen Sulfiden gebildet, wobei Pyrit, Kupferkies und Magnetkies die Hauptmasse bilden, die anderen Erze finden sich nur noch akzessorisch. Die Gangart besteht hauptsächlich aus Epidot, Pyroxen. Granat und Hornblende. Quarz sowie andere Gangartminerale treten nur untergeordnet auf. Neben den primären Verwachsungen werden auch eingehend die deszendenten Bildungen, hauptsächlich die Umbildung von Magnetkies, beschrieben. Abschließend wird auf die Entstehung des Vorkommens und eine eventuelle Deutung als Skarn eingegangen.

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Summary A new sulphide deposit in the Caledonides of Northern Norway is described from Gaskasjavri in Troms. The deposit and surrounding rocks have been formed under high metamorphosis, and are skarn-like. Magnetite, chalcopyrite, pyrite and pyrrhotite are the main products of the high-temperature mineralization, other sulphides occur only in small quantities. The gangue consists mainly of epidote, pyroxene, garnet and amphibole with small amounts of quartz and other gangue-minerals. This primary mineral association is described as well as the secondary formations due to descending water, especially those of pyrrhotite. Finally, the genesis of the deposit, and its possible interpretation as a skarn is discussed.

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Conditional use of mangrove habitats by fishes: Depth as a cue to avoid predators     

William?L.?EllisEmail author  Susan?S.?Bell 《Estuaries and Coasts》2004,27(6):966-976

The flooded intertidal zone in coastal estuarine systems (e.g., mangroves and salt marshes) is thought to provide nekton with both food and refuge from predators. The primary aim of this study was to identify the relative contribution of root structure, shading, and leaf litter, all characteristic features of mangrove forests, in shaping the intertidal distribution of tidally migrating fishes. We manipulated the structure and shade in 9-m² sample plots in a shallow, mangrove-fringed, intertidal embayment in Tampa Bay, Florida. In a separate field experiment, we compared fish association with standing mangrove leaf litter and bare sand substrate. Shade and leaf litter had a water depthdependent effect on the distribution of the fish; no effect was associated with the presence of mangrove roots. In shallow water (<45 cm), fish were captured primarily in plots without shade, but this distribution shifted progressively with increasing water depth, so that when water was greater than 55 cm most fish were captured in shaded plots. Fish were more frequently associated with, and feeding in, plots covered in leaf litter than bare sand plots. This relationship did not persist at depths greater than 15 cm because fish abundance declined gratly. Tethering experiments usingCyprinodon variegatus demonstrated that predation pressure was quadratically correlated with water depth (inflexion point approximately 60 cm). Our results suggest that small fishes will abandon well-lighted foraging grounds in favor of the potential refuge of shaded waters as water depth increases. We suggest that studies of intertidal nekton should be carefully interpreted in the context of water depth.  相似文献   

Conversion of carbonaceous material to graphite within the Greywacke Zone of the Eastern Alps   总被引：1，自引：0，他引：1  

Gerd?RantitschEmail author  Werner?Grogger  Christian?Teichert  Fritz?Ebner  Christian?Hofer  Eva-Maria?Maurer  Bernhard?Schaffer  Michael?Toth 《International Journal of Earth Sciences》2004,93(6):959-973

Morphology and reflectance of carbonaceous material (CM) in Late Carboniferous metasediments of the eastern Greywacke Zone (Eastern Alps) indicate a mixture of vitrinite, grainy textured and lamellar shaped particles. As imaged by high-resolution atomic-force microscopy, vitrinite and the grainy textured particles show mesophase structures which can be described as facetted nanocrystals within the carbon matrix. High-resolution transmission electron microscopy has revealed two types of microtextures representing different degrees of graphitization. The first type is characterized by elongated ring-shaped microtextures, whereas the second type is characterized by graphite lamellae and polygonal flakes with long-range ordered aromatic layers. In spite of the heterogeneity of the CMs, the geographical distribution of quantitative metamorphic parameter (Raman spectra parameter, X-ray diffraction pattern, microscopic reflectance) suggests a graphitization process which is promoted by advective heat transport during post-collisional processes. In a tentative pressure-time path, Late Cretaceous thrusting results in a turbostratic ordering of the aromatic layer. Ordering to long-range ordered aromatic layers was achieved during the Late Cretaceous-Paleogene exhumation of mid-crustal rocks beneath the eastern Greywacke Zone.  相似文献   

Introductory perspective on the COREF Project     

Yasufumi  Iryu  Hiroki  Matsuda  Hideaki  Machiyama  Werner E.  Piller  Terrence M.  Quinn  Maria  Mutti 《Island Arc》2006,15(4):393-406

Abstract Coral reefs are tropic to subtropic, coastal ecosystems comprising very diverse organisms. Late Quaternary reef deposits are fossil archives of environmental, tectonic and eustatic variations that can be used to reconstruct the paleoclimatic and paleoceanographic history of the tropic surface oceans. Reefs located at the latitudinal limits of coral‐reef ecosystems (i.e. those at coral‐reef fronts) are particularly sensitive to environmental changes – especially those associated with glacial–interglacial changes in climate and sealevel. We propose a land and ocean scientific drilling campaign in the Ryukyu Islands (the Ryukyus) in the northwestern Pacific Ocean to investigate the dynamic response of the corals and coral‐reef ecosystems in this region to Late Quaternary climate and sealevel change. Such a drilling campaign, which we call the COREF (coral‐reef front) Project, will allow the following three major questions to be evaluated: (i) What are the nature, magnitude and driving mechanisms of coral‐reef front migration in the Ryukyus? (ii) What is the ecosystem response of coral reefs in the Ryukyus to Quaternary climate changes? (iii) What is the role of coral reefs in the global carbon cycle? Subsidiary objectives include (i) the timing of coral‐reef initiation in the Ryukyus and its causes; (ii) the position of the Kuroshio current during glacial periods and its effects on coral‐reef formation; and (iii) early carbonate diagenetic responses as a function of compounded variations in climate, eustacy and depositional mineralogies (subtropic aragonitic to warm‐temperate calcitic). The geographic, climatic and oceanographic settings of the Ryukyu Islands provide an ideal natural laboratory to address each of these research questions.  相似文献   

Spitzer: the first 30 months     

Michael Werner 《Astronomy& Geophysics》2006,47(6):6.11-6.16

In his George Darwin Lecture, Michael Werner celebrates the achievements of the Spitzer Space Telescope, an observatory that owes much of its success to the fact that it is cool by design.  相似文献   

Behind the scenes: How transnational firms are constructing a new international division of labor in media work     

Susan Christopherson 《Geoforum》2006,37(5):739-751

Predictions that work in fields such as computer programming, architecture, and graphic design will be globally sourced have raised the specter of job losses among skilled workers in high wage economies. One of the most interesting cases tied to this controversy is that of so-called “runaway” motion picture and television production from the traditional center of entertainment media production in Los Angeles to non-US satellite production centers. Although runaway production is an old complaint in the entertainment media industries, the production location decisions of media entertainment firms since the mid-1990s look considerably different than those in the 1980s when a similar alarm was raised. Among the critical differences are: (1) the location of an expanded range of production activities in regions outside the “headquarters” location of Los Angeles; (2) the ability of transnational firms to access multiple, self-organized and networked pools of skilled labor in production locations outside Los Angeles; and (3) the expanded role of the sub-national state in reducing the overall production costs of transnational firms, including those attendant to their use of skilled labor pools. The current controversy provides an opportunity to consider how transnational firms use international out-sourcing to address their need for high-skilled and specialized labor in the production process. It also contributes to the on-going theoretical debate over how transnational firms are combining the advantages to be derived from territorial agglomeration with those of substitutability of labor skills in multiple locations.  相似文献   

Aspartic acid racemization dating of Holocene brachiopods and bivalves from the southern Brazilian shelf, South Atlantic     

Susan L. Barbour Wood  Richard A. Krause Jr.  John Wehmiller 《Quaternary Research》2006,66(2):323-331

The extent of racemization of aspartic acid (Asp) has been used to estimate the ages of 9 shells of the epifaunal calcitic brachiopod Bouchardia rosea and 9 shells of the infaunal aragonitic bivalve Semele casali. Both taxa were collected concurrently from the same sites at depths of 10 m and 30 m off the coast of Brazil. Asp D/L values show an excellent correlation with radiocarbon age at both sites and for both taxa (r²_{Site 9 B. rosea} = 0.97, r²_{Site 1 B. rosea} = 0.997, r²_{Site 9 S. casali} = 0.9998, r²_{Site 1 S. casali} = 0.93). The Asp ratios plotted against reservoir-corrected AMS radiocarbon ages over the time span of multiple millennia can thus be used to develop reliable and precise geochronologies not only for aragonitic mollusks (widely used for dating previously), but also for calcitic brachiopods. At each collection site, Bouchardia specimens display consistently higher D/L values than specimens of Semele. Thermal differences between sites are also notable and in agreement with theoretical expectations, as extents of racemization for both taxa are greater at the warmer, shallower site than at the cooler, deeper one. In late Holocene marine settings, concurrent time series of aragonitic and calcitic shells can be assembled using Asp racemization dating, and parallel multi-centennial to multi-millennial records can be developed simultaneously for multiple biomineral systems.  相似文献   

Global environmental change: conceptualising the growing challenge for cities in poor countries   总被引：1，自引：0，他引：1  

Susan Parnell  David Simon  Coleen Vogel† 《Area》2007,39(3):357-369

Ongoing urbanisation makes cities a key focus for global environmental change (GEC) research, creating an imperative for a new, city-scale, research agenda. The vulnerability of urban populations to the multiple stresses of GEC lies at the core of overlapping domains of knowledge that could be better integrated in advancing research. The urban development, global change and disasters literatures are fragmented and reveal fundamental cleavages over the role that government could play in mitigating vulnerability to multiple threats and challenges. Important empirical gaps exist, especially on cities of the South. While there are significant knowledge gaps and numerous tensions within and between schools of thought, this overview suggests useful entry points for framing an invigorated research agenda on urban GEC.  相似文献   

Dynamics of coupled human-landscape systems   总被引：2，自引：0，他引：2  

B.T. Werner  D.E. McNamara 《Geomorphology》2007,91(3-4):393

A preliminary dynamical analysis of landscapes and humans as hierarchical complex systems suggests that strong coupling between the two that spreads to become regionally or globally pervasive should be focused at multi-year to decadal time scales. At these scales, landscape dynamics is dominated by water, sediment and biological routing mediated by fluvial, oceanic, atmospheric processes and human dynamics is dominated by simplifying, profit-maximizing market forces and political action based on projection of economic effect. Also at these scales, landscapes impact humans through patterns of natural disasters and trends such as sea level rise; humans impact landscapes by the effect of economic activity and changes meant to mitigate natural disasters and longer term trends. Based on this analysis, human-landscape coupled systems can be modeled using heterogeneous agents employing prediction models to determine actions to represent the nonlinear behavior of economic and political systems and rule-based routing algorithms to represent landscape processes. A cellular model for the development of New Orleans illustrates this approach, with routing algorithms for river and hurricane-storm surge determining flood extent, five markets (home, labor, hotel, tourism and port services) connecting seven types of economic agents (home buyers/laborers, home developers, hotel owners/ employers, hotel developers, tourists, port services developer and port services owners/employers), building of levees or a river spillway by political agents and damage to homes, hotels or port services within cells determined by the passage or depth of flood waters. The model reproduces historical aspects of New Orleans economic development and levee construction and the filtering of frequent small-scale floods at the expense of large disasters.  相似文献   

Application of stacking and inversion techniques to three-dimensional wide-angle reflection and refraction seismic data of the Eastern Alps   总被引：1，自引：0，他引：1  

Michael Behm  Ewald Brückl  Werner Chwatal  Hans Thybo 《Geophysical Journal International》2007,170(1):275-298

We present new methods for the interpretation of 3-D seismic wide-angle reflection and refraction data with application to data acquired during the experiments CELEBRATION, 2000 and ALP 2002 in the area of the Eastern Alps and their transition to the surrounding tectonic provinces (Bohemian Massif, Carpathians, Pannonian domain, Dinarides). Data was acquired on a net of arbitrarily oriented seismic lines by simultaneous recording on all lines of seismic waves from the shots, which allows 2-D and 3-D interpretations. Much (80%) of the data set consists of crossline traces. Low signal to noise (S/N) ratio in the area of the young orogens decreases the quality of travel time picks. In these seismically heterogeneous areas it is difficult to assign clearly defined arrivals to the seismic phases, in particular on crossline record sections.
In order to enhance the S/N ratio, signal detection and stacking techniques have been applied to enhance the Pg -, Pn - and PmP phases. Further, inversion methods have been developed for the interpretation of WAR/R-data, based on automated 1-D inversion ( Pg ) and the application of the delay time concept ( Pn ). The results include a 3-D velocity model of the crust based on Pg waves, time and depth maps of the Moho and a Pn -velocity map. The models based on stacked data are robust and provide a larger coverage, than models based on travel time picks from single-fold (unstacked) traces, but have relatively low resolution, especially near the surface. They were used as the basis for constructing models with improved resolution by the inversion of picks from single-fold data. The results correlate well with geological structures and show new prominent features in the Eastern Alps area and their surrounds. The velocity distribution in the crust has strong lateral variations and the Moho in the investigation area appears to be fragmented into three parts.  相似文献