Electric conductivity of Fe-Ti minerals     

Marcela Laštovičková  Vladimír Kropáček  Reviewer F. Janák 《Studia Geophysica et Geodaetica》1979,23(2):199-203

a mua n¶rt;um u mnama auum uma mnam 200–900°C ¶rt; ummuu u ama Fe-Ti ua (amum,amum, uum u mu). n numa ¶rt;a n¶rt;m mun au mn¶rt;mu u au uu amuauu. a ma u mm naam n¶rt;u m-auu m¶rt;.  相似文献   

An analysis of the palaeomagnetic field     

Miroslav Krs  Reviewer J. Kropáček 《Studia Geophysica et Geodaetica》1978,22(4):368-389

Summary The paper is devoted to a critical evaluation of the hypothesis of the prevalent character of the palaeomagnetic field in the course of the whole Phanerozoic. The study ties in with the synthetic processing of all so far published palaeomagnetic data for Eurasia and Africa respecting some of the models ensuing from the concept of plate tectonics. Initial material for testing the dipolar hypothesis was obtained by statistical processing of the palaeomagnetic pole positions and by analyzing the values of the so-called palaeorotation, the palaeoinclination difference and of palaeodivergence. It was shown that, by defining tectonically stable blocks (plates, palaeoplates) within the scope of the Eurasian continent and within the scope of the African continent as a whole, data were obtained bringing evidence of the predominating dipolar character of the mean geomagnetic field for the period from the Quaternary to the Cambrian, with the exception of the Silurian which has not been studied sufficiently. The deviations of the palaeomagnetic directions from the direction of the dipolar field within the scope of the stable blocks have the character of a Gaussian distribution and the standard deviations only amount to a few degrees.  相似文献   

Error propagation in absolute geodetic networks a continuous approach     

Kai Borre  Reviewer L. Kubáček 《Studia Geophysica et Geodaetica》1978,22(3):213-223

Summary Studies of error propagation in geodetic networks of an absolute type have already been carried through by several authors using various mathematical techniques. The geodetic elasticity theory relies on a continuation of the actual, discrete network. The traditional observation and normal equation matrices are substituted by partial differential equations with corresponding boundary conditions. The continuous approach only reflects the global error behaviour opposed to the discrete case, and produces only asymptotic results. An advantage of the method is that we may directly profit from existing mathematical knowledge. The fundamental solution of the partial differential equations acts as a formal covariance function and yields the best linear unbiased estimates for estimable functions of the adjustment parameters. Levelling networks and networks with distance and azimuth measurements are studied in this framework.Invited paper presented at the International Symposium on Optimisation of Design and Computation of Control Networks, Sopron, July 4–8, 1977.  相似文献   

Self-reversal of spontaneous magnetization of natural cassiterite     

Vladimír Kropáček 《Studia Geophysica et Geodaetica》1968,12(1):108-110

Резюме Рассматривается случай экспериментального обнаружения самообращения спонтанной намагниченности на образце естественного касситерита. Самообращение спонтанной намагниченности вызывается, по-видимомы, влиянием различий температурной зависимости намагниченности в отдельных зонах, где обнаруживается повышенная концентрация ионов железа в кристаллической решетке касситерита. Аномальный ход изменений температурной зависимости намагниченности насышения сравнивали как с обычным ходом изменений температурной зависимости намагниченности насышения двух дальнейших образцов касситерита, так и со свойствами естественной остаточной намагниченности. В габлицах приводятся химический состав отдельных образцов и соответствуюшие магнитные характеристики (значения намагниченности насыщения, температуры Кюри и температуры компенсации, а также значения естественной остаточной намагниченности и названия месторождений образцов).

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Address: Bočni II, Praha 4-Spořilov.  相似文献   

The magnetic anisotropy of basalts and its variations under oxidation of titanomagnetites     

Josef Bochníček  Vladimír Kropáček  Reviewer M. Krs 《Studia Geophysica et Geodaetica》1977,21(3-4):336-342

Summary Using four samples of basaltic rocks from the Bohemian Massif, Nos 201, 202, 206 and 218, the curves of rotational moments in a magnetic field of 4 × 10⁵ A/m were studied as a function of the degree of oxidation of titanomagnetites. The amplitudes of the individual harmonics were determined by harmonic analysis for samples oxidized to various degrees. It was found that the proportion of the harmonic A ₁ withsin increases with the degree of oxidation. Simultaneously, the anisotropy of the magnetic susceptibility changes in a field of 60 A/m and the structure changes from linearly parallel to plane parallel.  相似文献   

Water Quality Control in Impoundments     

J. Chalupa  L. Fiala  J. Popovský  V. Slde ek  P. Va&#x;ata 《洁净——土壤、空气、水》1985,13(1):1-16

This report on a seminar of the Water Research Institute in Prague deals with the methodological aspects of the measurement and evaluation of data for the water quality in impoundments in the CSSR mainly with respect to: the assessment of external causes, especially of anthropogenic influences in the catchment area, on the water quality (eutrophication, humic substances, trace elements), of the multi-purpose utilization of impoundments, the classification and development of the water quality in impoundments, the intensified utilization of impoundments as well as the influences of sediments and the effect of piscicultural measures on the water quality. The paper is subdivided into the following chapters: system of measurement network and analysis, stratification number of samples, number of the criteria to be investigated, extreme periods of discharge, multi-purpose utilization of impoundments, eutrophication, fish stocks.  相似文献   

Tagungsbericht. 3rd International Course and Symposium on the Biology of Pollution in Mexico City – August 5–8, 1985     

F. Rivera  V. Slde ek 《洁净——土壤、空气、水》1986,14(4):443-445

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The Puncoviscana trough — a large basin of Late Precambrian to Early Cambrian age on the pacific edge of the Brazilian shield     

Pavel JeŽek Dipl.-Geol.  Dr. Arne P. Willner  Prof. Dr. Florencio G. AceÑolaza  Prof. Dr. Hubert Miller 《International Journal of Earth Sciences》1985,74(3):573-584

During the Late Precambrian to Early Cambrian a large basin with a homogeneous psammitic-pelitic sediment fill existed in the area of the NW-Argentine Andes. It is now exposed in different tectonic levels. This basin of meridional elongation was situated on a stable continental margin at the western edge of the Brazilian shield. It was underlain by segmented older continental crust. According to the modal and chemical composition of the greywackes and subgreywackes a predominant metasedimentary source may be supposed. Four clastic facies types indicate a transport by gravity currents within a submarine fan system, while massive red pelites represent cut-off periods, and rare carbonates deposition on rises. The gravity currents derived from easterly directions. The sedimentation age is proved by a rich ichnofauna and some medusoid impressions.

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Zusammenfassung Im Jungpräkambrium bis Unterkambrium existierte im Bereich der NW-argentinischen Anden ein ausgedehnter Trog mit homogener psammitisch-pelitischer Füllung, die heute in verschiedenen Gebirgsstockwerken aufgeschlossen ist. Dieses Becken lag an einem stabilen Kontinentalrand im Westen des Brasilianischen Schildes und war von segmentierter älterer, kontinentaler Kruste unterlagert. Nach der modalen und chemischen Zusammensetzung der Grauwacken und Subgrauwacken sind überwiegend metasedimentäre Herkunftsgesteine anzunehmen. Vier klastische Faziestypen lassen auf Transport durch Trübeströme in submarine Fächer schließen, während mächtige Rotpelite Ruhezeiten und die seltenen Karbonate Ablagerungen auf Schwellen anzeigen. Die Schüttungen stammen aus östlichen Richtungen. Das Sedimentationsalter ist durch eine reichhaltige Ichnofauna und einige Medusenabdrücke dokumentiert.

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Résumén Durante el Precámbrico superior hasta el Cámbrico inferior en los Andes del NW Argentino se extendía una larga cuenca rellena de sedimentos psamo-pelíticos homogéneos, que hoy afloran en distintos pisos tectónicos. Esta cuenca de elongación meridional estaba situada en un margen continental estable al lado occidental del escudo brasileño, sobre corteza continental segmentada más antigua. Según su composición modal y química, las grauvacas y subgrauvacas derivaron predominantemente de rocas metasedimentarias. Cuatro tipos de facies clásticas indican su transporte en corrientes de gravedad, provenientes del este, y sedimentación en conos submarinos. Pelitas rojas macizas representan períodos de sedimentación pelágica, mientras que los escasos carbonatos se depositaron en dorsales. Una icnofauna amplia y algunas impresiones de medusoides documentan la edad de sedimentación.

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Changes of the magnetic susceptibility and its anisotropy of basalts by oxidation of titanomagnetites     

Vladimír Kropáček  Reviewer F. Janák 《Studia Geophysica et Geodaetica》1976,20(2):178-185

Summary The changes of the anisotropy of the magnetic susceptibility of alkaline Tertiary basalts under titanomagnetite oxidation are investigated. The oxidation of the titanomagnetites was achieved by the following thermal processing of rock samples: 60 mins at a temperature of 400°C, 300 mins at T=400°C and 60 mins at T=500°C. It is shown that considerable changes of the values of the magnetic susceptibility, as well as of the degree of the preferred orientation of the titanomagnetites and of the ellipsoid of anisotropy in the sample occur as a result of the oxidation of titanomagnetites, contained in the samples, due to the said thermal processing. Moreover, the micro-structure of the grains, created by the oxidation of the titanomagnetites, causes the mostly linearly parallel configuration to change to a planar-parallel configuration.  相似文献   

Mercury in water,organisms and sediments from a section of the Turkish Mediterranean coast     

G Tunçel  G Ramelow  T.I Balkaş 《Marine pollution bulletin》1980,11(1):18-22

Samples of water, marine organisms and sediment collected along the Turkish Mediterranean coast in the vicinity of Mersin were analysed for total mercury. The levels of mercury found in the samples from this area are generally low in comparison with the levels found in other regions of the Mediterranean.  相似文献