Metallogeny of gold in the Fennoscandian Shield     

G. Gaál  K. Sundblad 《Mineralium Deposita》1990,25(1):S104-S114

Gold occurs in a number of different ore types in the Fennoscandian Shield ranging in age from Late Archean to Late Proterozoic. Until recently, the metal was exploited primarily as a byproduct in volcanogenic massive sulphide deposits but during the 1980s more gold mines have been opened than during any other episode in the mining history of northern Europe. The occurrence of gold in the Fennoscandian Shield is reviewed in the context of the major tectonostratigraphic units:

1.	In the Karelian Province, gold is hosted by greenstone belts of the Archean basement complex e.g. at Ilomantsi, eastern Finland. Greenstone belts of the Nordkalott Province, which are interpreted as part of an Early Proterozoic cover sequence, contain gold deposits associated with copper (Bidjovagge, Saattopora and Pahtohavare). Gold is also associated with cobalt in the metasomatically altered Early Proterozoic cover in north-eastern Finland (Meurastuksenaho and Juomasuo).
2.	In the Svecofennian Domain, the major gold deposits were generated during the emplacement of 1.92–1.87 Ga old accretional magmatism. These deposits occur in the northeastern part of the Svecofennian Domain, close to the Archean-Proterozoic boundary. They comprise two major types: (a) the porphyry-type and shear-zone gold hosted by tonalite at Tallberg, Laivakangas, Kopsa and Osikonmäki; (b) as a component of volcanogenic massive sulphide deposits (e.g. Holmtjärn, Boliden and Pyhäsalmi). Other types are: (c) gold-bearing quartz-alumina alteration zones formed during the 1.92–1.87 Ga magmatic period (Enåsen); (d) gold in massive sulphide and iron ore deposits in Bergslagen.
3.	Gold associated with 1.84–1.54 Ga granites has been reported from several sites in the Shield, including quartz veins and contact-metasomatic deposits. In addition, shear-zone-related gold deposits post-dating these granites have been identified in southeastern Sweden (Ädelfors).
4.	In the Sveconorwegian Domain, the gold deposits at Bleka, Eidsvoll, Glava and Hamas are associated with shear zones which developed penecontemporaneously with the intrusion of late (1.0–0.9 Ga) granites.

These metallogenic features, deposit modelling and economic properties of the known occurrences suggest that the potential for new gold discoveries is highest in Late Archean to Early Proterozoic greenstone belts and in Early Svecofennian tonalite plutons. The gold potential of the Sveconorwegian Domain is also worth further consideration.  相似文献   

Oscillatory motions in an active prominence     

B. Vršnak  V. Ruždjak  R. Brajša  F. Zloch 《Solar physics》1990,127(1):119-128

Different types of oscillatory motions were detected in the late phases of eruption of a prominence. We found oscillations of the prominence axis and diameter with periods of 4.3 and 9.1 min, corresponding to the eigenmodes m = 4 and m = 8 with a damping factor 4.6 × 10^–3 s^–1. A period about 4.5 min was found for oscillations of the pitch angle of the helically twisted filaments. The m = 2 and m = 3 eigenmodes could be also identified and they led to the final relaxation of the prominence axis. The observations are compared with a model in which we consider forces acting in a curved, cylindrical magnetic tube anchored at both ends in the photosphere and carrying an electric current. The stability of the prominence is discussed.  相似文献   

Kinetics of the leaching of mechanically activated berthierite,boulangerite and franckeite     

M. Achimovičová  P. Baláž 《Physics and Chemistry of Minerals》2008,35(2):95-101

In this study, changes in surface area, morphology and leachability of antimony from mechanically activated berthierite—FeSb₂S₄, boulangerite—Pb₅Sb₄S₁₁ and franckeite—FePb₅Sn₃Sb₂S₁₄ by a high-energy planetary mill were investigated. It appears that a selective extraction of antimony from these complex sulphosalts in alkaline solution of sodium sulphide is positively affected by mechanical activation. The influence of milling on mineral particle size and shape was studied by scanning electron microscopy. The temperature dependencies of berthierite alkaline leaching were investigated in an interval of 323–363 K. Resulting experimental activation energies E _a were 0.11 and 6.78 kJ mol⁻¹ for mechanically activated berthierite due to a break of Arrhenius plot. The values E _a are characteristic for a process controlled by diffusion as the rate-controlling step of leaching reaction.  相似文献   

Sédimentologie et paléontologie des paléoenvironnements côtiers rupéliens de la Molasse marine rhénane dans le Jura suisse     

Laurent Picot  Damien Becker  Lionel Cavin  Claudius Pirkenseer  Frédéric Lapaire  Gaëtan Rauber  Peter A. Hochuli  Silvia Spezzaferri  Jean-Pierre Berger 《Swiss Journal of Geoscience》2008,101(2):483-513

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Monotonic and cyclic modeling of interface between geotextile and gravelly soil     

Ga Zhang  Liping Wang  Jian‐Min Zhang 《国际地质力学数值与分析法杂志》2010,34(13):1346-1361

This paper describes a modified elasto‐plasticity damage model to capture monotonic and cyclic behavior of the interface between a geotextile and gravelly soil. New damage variable and shear strength criterion are introduced on the basis of test observations. The formulations of the modified model are obtained by extending those of the original interface model. The model parameters with physical meaning are easily determined from a group of cyclic shear tests and a confining compression test. The model predictions are compared with the results of a series of direct shear tests and large‐scale pullout tests. The comparison results demonstrate that the model accurately describes the monotonic and cyclic stress–strain relationship of the interface between a geotextile and gravelly soil while capturing new characteristics: (1) the strength that is nonlinearly dependent on the normal stress; (2) significant shear strain‐softening; (3) the comprehensive volumetric strain response with dependency on the shear direction; and (4) the evolution of behavior associated with the changes in the physical state that includes the geotextile damage. This model is used in a finite element analysis of pullout tests, indicating that the tensile modulus of a geotextile has a significant effect on the response of the geotextile–gravel system. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Étalonnage des photomètres du ciel nocturne en service pendant l'agi et la CGI     

František Link  Luděk Neužil 《Studia Geophysica et Geodaetica》1962,6(2):193-201

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Surface sediments pollution due to shipwreck s/s “Stuttgart”: a multidisciplinary approach     

Justyna Rogowska  Błażej Kudłak  Stefan Tsakovski  Agnieszka Gałuszka  Gabriela Bajger-Nowak  Vasil Simeonov  Piotr Konieczka  Lidia Wolska  Jacek Namieśnik 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(7):1797-1807

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Soil–foundation–structure interaction and vulnerability assessment of the Neoclassical School in Rhodes,Greece     

Anna Karatzetzou  Dimitris Pitilakis  Meta Kržan  Vlatko Bosiljkov 《Bulletin of Earthquake Engineering》2015,13(1):411-428

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Acquiring reference parameters of masonry for the structural performance analysis of historical buildings   总被引：1，自引：1，他引：0  

Meta Kržan  Samo Gostič  Serena Cattari  Vlatko Bosiljkov 《Bulletin of Earthquake Engineering》2015,13(1):203-236

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Electrochemical Degradation of Triketone Herbicides and Identification of Their Main Degradation Products          下载免费PDF全文

Milica Jović  Dragan Manojlović  Dalibor Stanković  Uroš Gašić  Dejan Jeremić  Ilija Brčeski  Goran Roglić 《洁净——土壤、空气、水》2015,43(7):1093-1099

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