Superposition of Variscan ductile shear deformation on pre-Variscan mantled gneiss structure (Catherine dome,Erzgebirge, Bohemian massif)     

Bedřich Mlčoch  Karel Schulmann 《International Journal of Earth Sciences》1992,81(2):501-513

Three tectonometamorphic events have been recognized in the crystalline rocks of the Catherine mantled gneiss Dome (CD) in the central Erzgebirge. The first tectonometamorphic event is characterized by the acquisition of a S1–S2 metamorphic foliation, development of F2 isoclinal partly syn-schistose folding and intrusion of early synkinematic granites. P-T conditions correspond to higher amphibolite facies metamorphism and culminate in anatexis. A diapiric intrusion of Cambro-Ordovician muscovite-biotite porphyritic granite has verticalized the S2 foliation and is responsible for the genesis of the classical mantled gneiss dome. Oblate strain and orthorhombic diffuse c-axis patterns are typical of the marginal parts of the dome.The whole rock sequence was subsequently affected by westward oriented heterogeneous Variscan ductile shearing under the conditions reaching amphibolite fades. A strongly non-coaxial deformation has partly overprinted the earlier fabrics in anatectic orthogneiss and produced augen-orthogneiss from porphyritic granite in the central part of the CD dome. Prolate to plane strain fabrics, oblique quartz c-axis patterns and a widespread occurrence of S-C fabrics are the most characteristic features of this phase.

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Zusammenfassung Im Kristallin des Katherinenberg mantled gneiss dome im mittleren Erzgebirge wurde eine dreiphasige tektono-metamorphe Entwicklungsgeschichte nachgewiesen.Das alte Stadium stellt bereits eine polyphase Entwicklung dar. Es wird durch die Anlage eines penetrativen metamorphen Lagenbaus (syn D₁ — syn D₂), durch F₂ früh Isoklinalfalten, sowie durch die Intrusion frühkinematischer z. T. anatektischer Granite charakterisiert. PT-Daten belegen amphibolitfazielle Bedingungen, die lokal zu Anatexis führen.Diapirartige Intrusionen kambro-ordovische, porphyrische Zweiglimmergranite bewirkten eine sehr unterschiedliche z. T. subvertikale Raumlage der regionalmetamorphen Einheiten. Diese Intrusionen des zweiten Stadiums sind verantwortlich für die Entstehung des eigentlichen mantled gneiss dome. Oblat Gefüge und diffuse Kreuzgürtel-Verteilungen der Quarz c-Achsen sind typisch für die Randbereiche dieses Gneisdomes.Während des jüngsten Stadiums prägen bzw. überprägen westvergente duktile Scherprozesse bei Bedingungen der niedriggradigen Amphibolitfazies die Gefüge. Schiefgürtel-Verteilungen der Quarz c-Achsen und S-C Gefüge charakterisieren diese jüngste, variszische Phase.

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Résumé Trois événements tectono-métamorphiques ont été reconnus dans les roches cristallines du dôme de gneiss coiffé de Catherine (Erzgebirge oriental). Le premier de ces événements est caractérisé par l'acquisition d'une foliation S_1–2, le développement de plis isoclinaux F₂ partiellement synschisteux et l'intrusion de granites syntectoniques précoces. Les conditions (P, T) correspondent au facies supérieur des amphibolites et atteignent l'anatexie. L'intrusion diapirique d'un granite à deux micas cambro-ordovicien a verticalisé la foliation S_1–2 et est responsable de la genèse du dôme de gneiss coiffé. Une déformation par aplatissement et des fabriques orthorhombiques diffuses des axes c du quartz caractérisent les zones marginales du dôme.L'ensemble des terrains a été ensuite affecté par un cisaillement ductile varisque hétérogène à vergence ouest, dans les conditions du facies inférieur des amphibolites. Une déformation fortement noncoaxiale a transposé partiellement les structures précoces des orthogneiss anatectiques et a transformé les granites porphyriques de la partie centrale du dôme de Catherine en orthogneiss oeillés. Cette phase est caractérisée par des fabriques obliques pour les axes c du quartz et par de fréquentes structures s-c.

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Matrix approach to the solution of electromagnetic induction in a spherically layered earth     

Karel Pěč  Zdeněk Martinec  Jana Pěčová  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1985,29(2):139-162

Summary Matrix formulae for the intensities of the M- and E-fields have been derived. They have been applied to express the apparent resistivity, the transfer function, as well as the frequency equation determining the frequencies of free motion of the M- and E-waves. A fast algorithm for computing the transfer function and the apparent resistivity has been suggested.

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Frequency band of mirroring and bands of increased transmissivity of ULF waves through the ionosphere     

Karel Prikner  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1982,26(1):96-101

Summary Using methods of numerical modelling of the propagation of ULF waves through the ionosphere, the characteristics of the vertical flux of electromagnetic energy are analysed in the ULF range — at the outer boundary of the modelled ionosphere (altitude 1000 km) the reflexibility and penetrability of the energy, at the Earth's surface the transmissivity of the energy. The existence of two frequency bands is proved within the ULF range with different forms of ionospheric wave filtration: a) The band of extremely low frequencies, f<0.1–0.2 Hz (pc3–5 and Pc2 pulsation ranges) with a mirroring effect of the ionosphere-Earth system, but with small absorption; b) the band f>0.2 Hz (the Pc1 range) with increased absorption, but with resonance windows and wave emissions with a very well defined frequency structure.  相似文献   

Characteristics of the ionospheric correction in ULF wave diagnostics of the magnetosphere     

Karel Prikner  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1982,26(2):201-207

Summary Amplitude and energy correction character istics of the vertical propagation of ULF wave from the magnetosphere through the ionosphere to the Earth's surface, necessary for micropulsation wave diagnostics of the magnetosphere by means of ground-based observations, are introduced on the basis of matrices ofR–T coefficients [1–3]. The coefficients of vertical reflexibility, penetrability, transmissibility (or limpidity) and the absorption of the electromagnetic energy flux are defined, as well as analogous coefficients in the dimensions of the magnetic amplitude of the ULF wave, propagating through the given layer of the ionosphere. An examplary model of the ionosphere is used to demonstrate the frequency variations of these characteristics in the ULF wave range.  相似文献   

Anomalous induction in the Carpathians     

Jerzy Jankowski  Antoni Szymański  Karel Pěč  Václav Červ  Václav Petr  Jana Pěčová  Oldřich Praus  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1977,21(1):35-57

nuam mam uu auauaum n aumua ¶rt; a 9 n mau ¶rt; nu No V, na anam. ma uam a aa u¶rt;uu aau ¶rt; uu u mau anamau. m m u¶rt;uu u aauuaa amma aamumua aa ma. ¶rt;a a m¶rt; mau ¶rt; aumua u mm a¶rt;u n a m u mau. uamua aau ¶rt;m u mu ma, m m ¶rt;u u umu m n. maum aamumuu n nma mmuuu aauu aumau ¶rt; m ¶rt;- ¶rt;¶rt;muu mm ¶rt; nu u m¶rt; am.

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A substantial part of this paper was presented at the IAGA symposium Relations between External and Internal Magnetic Variations, XVI. IUGG General Assembly, August–September 1975, Grenoble.  相似文献   

Long period variations of the geomagnetic field and their spatial distribution in Europe     

Jana Pěčová  Oldřich Praus  Karel Pěč  Reviewer A Janáčková 《Studia Geophysica et Geodaetica》1977,21(2):148-158

a 27 nu amu ama m¶rt;au nma aaua ¶rt; nu nma anum¶rt; 27-¶rt; auauu u ÿeau nu¶rt;au 13–14 u 9 ¶rt;. mam an¶rt;u nma anum¶rt; Z u H mau a n nuuuu auauuu uuP ₁ (cos ) u P ₁ /, mmm. mau mau a um auumu mau auau ¶rt; mmu mu Z/H ¶rt; a¶rt; amuu. au ¶rt; mmuuu u umu a¶rt;au muu ¶rt; ¶rt;am uau mu ¶rt;¶rt;mmu mu u. a aaua au mu Z/H ¶rt;m u uam n u m aa amu.  相似文献   

Dispersion and amplitudes of love waves for some models of the earth's crust and mantle     

Karel Pěč  Oldřich Novotný  Reviewer J. Vaněk 《Studia Geophysica et Geodaetica》1976,20(1):10-38

Summary The properties of the partial derivatives of dispersion curves, amplitudes and theoretical seismograms, in particular the occurrence of short-period phases, are studied on four crustmantle models. The individual models differ in the number of low-velocity channels. The fundamental and first higher mode of Love waves are studied in detail.  相似文献   

Beglaubigung der Dimension astronomisch-geodätischer Netze der ČSSR und Udssr aus Messungen mit dem Geodimeter NASM-2A     

Karel Kučera  Rezensent B. Delong 《Studia Geophysica et Geodaetica》1973,17(4):290-294

Summary A method is described, based on the calculus of observations, of testing the transferring of a length dimension by means of invar wires from the national standard via the geodetic comparative base to field geodetic bases, assuming that some of them have been measured electrooptically. The method is demonstrated on Czechoslovak and Soviet bases. In both cases the transfer of the length was proved to be successful. It was also found that, as regards the accuracy, it is immaterial whether the given base is measured electro-optically as a whole or in parts.  相似文献   

The elastic constants of crystalline limestone computed from the velocities of body waves     

Karel Klíma  Reviewer V. Červený 《Studia Geophysica et Geodaetica》1973,17(3):255-260

m¶rt; uu nu nm u m n¶rt; , nua [4], una ¶rt; aa uma u um aumnuu. ma amuaa amu ¶rt; nm nu nm, m annuum uamuu u ¶rt;uauu ma n¶rt; . m u mu nm um ¶rt;a, nau au. ma ¶rt;a¶rt;amu nm u m n¶rt; n¶rt;um m m au.  相似文献   

Numerical solution to the problem of ionoshperic filtration of ULF waves in thePc1 range. the total wave field inside the ionospheric transition layer     

Karel Prikner  Vladimír Vagner 《Studia Geophysica et Geodaetica》1991,35(2):90-99

Summary This article is a continuation of the methodological series of the author's papers[2–4] related to the problem of numerical modelling of ionospheric filtration of signals in the Pc1 range of micropulation frequencies. A matrix method of treating the total wave field within the ionospheric transition layer is presented in connection with the total wave fields determined at both boundaries of the ionospheric transition layer. The computation is based on the method of thin layers (homogeneous) in a finely stratified, inhomogeneous and anisotropic (magneto-active) ionosphere. The results can be used in constructing automated computation algorithms which add considerably to the applications of the method in question[2–4].  相似文献