Beitrag Zur Ökonomie Der Ausnützung Von Luftaufnahmen

Résumé L'auteur décrit une combinaison de l'aérotriangulation en bloc — le bloc étant obtenu par raccordement de bandes — et de l'orthophotoplan. Ce procédé topographique largement automatisé est convenable pour un terrain montagneux et mal accessible (Fig. 1; Tab. 1, 2). L'auteur prouve par une analyse théorique de même que par des travaux expérimentaux et de routine qu'il est possible de contrôler le gauchissement des blocs à base de leurs écarts, constatés sur le recouvrement des bandes de clichés et que le nombre des points de repère est réduit au minimum (Fig. 2, 3; Tab. 1).

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Herrn Prof. Dr. Frantiek Fiala zum 90-sten Geburtstag gewidmet     

Zur Analyse der Genauigkeit von mehrmals mit einer Gravimetergruppe gemessenen gravimetrischen Verbindungen

Summary In order to evaluate the accuracy of measurements repeated by a set of gravimeters the semi-systematic errors ₂ and ₃ were introduced besides the random error ₁ in[1]. It is shown that Eqs.(10) and(11), given in[1], should not be used to determine these errors, but Eqs.(8) and(9).     

Velocity anisotropy and symmetry of dunite fabric

Summary From the space distribution of P- and S-wave velocities, determined at a hydrostatic pressure of 1 GPa, complete sets of elastic constants were calculated for the Twin Sisters dunite. It was found that orthorhombic symmetry is a reasonable approximation for the dunite sample; with one exception the deviations of the individual constants, determined from different waves, do not exceed a few percent. As a seismological application a simple model of a 120 km thick lithosphere, formed by the dunite, was considered for calculating the differences in the time arrivals of SV and SH waves. The greatest time differences, about 3s, were obtained in the vertical plane containing the direction of the greatest P-wave velocity, however, for the real lithosphere we estimate effects which only cause differences of the order of 1s.     

Investigation of gravimetric records at non-tidal frequencies

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Presented at the meeting of Working Group 3.3. of the KAPG (Prague, November 1975).     

ОБЪЕКТИВНЫЙ ПРОГНОЗ АНОМАЛЬНЫХ УСЛОВИЙ ПОГОДЫ НА ТЕРИТОРИИ ЧСР С ИСПОЛЬЗОВАНИЕМ ЧИСЛЕННЫХ ПРОГНОЗОВ ПОЛЕЙ ДАВЛЕНИЯ И ТЕМПЕРАТУРЫ

Summary There is presented a method of classification of synoptic situations, which are characterized by heights of surfaces1000, 850 and500 mbar, temperatures at the surface850 mbar (eventually by moisture at the surface850 mbar) in 90 points of the square grid. Typical synoptic situations are defined with the respect to above-normal and sub-normal temperatures, above-normal number of fog and thunderstorms (summer and winter) on the territory of Czechoslovakia. The method of exploatation of typical synoptic situations for automated middle range forecast is described.     

Determination of the gravitational effect of extensive spherical laminae (platforms) using generalized Talwani's method

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Geochronology of a polymetamorphic and anatectic gneiss region: The moldanubicum of the area Lam-Deggendorf,eastern Bavaria,Germany

Rb-Sr isotopic analyses of whole-rocks and biotite and U-Th-Pb analyses of zircon and monazite reveal regional metamorphic events for the Ordovician (Caledonian metamorphism) and the Carboniferous (Variscan=Hercynian orogeny), both accompanied by anatexis. The extent of the Caledonian and Variscan anatexis, however, cannot be evaluated, so far, because the field petrographic criteria are not sufficient to distinguish clearly between early and late Paleozoic anatexites. Evidence for a Precambrian metamorphism has not been found. Rb-Sr whole-rock isochrons obtained on leucosomes and melanosomes of partially molten paragneisses are interpreted as a minimum age of the second, early Variscan anatexis. The alternative explanation of the isochrons as a result of local Sr isotopic redistribution without a melt involved is considered less likely. Concordant and nearly concordant zircon ages (318–335 m.y.) of a coarse-grained granite and of diatexites are regarded as evidence for an intensive early Variscan granitization and palingenesis. Concordant zircon ages of diorite dykes, crosscutting the anatexites, establish a lower time limit of 309–312 m.y. for the Variscan anatexis. Rb-Sr ages of biotite (310-290 m.y.) indicate the end of the Variscan metamorphism. Estimates of the time of sedimentation or diagenesis based on Rb-Sr whole-rock analyses for some metasediment series in the north of the area yield maximum ages of 550 m.y., provided that Rb and Sr migration did not exceed substantially the extent of the outcrops (30–500 m) between the time of diagenesis and the Ordovician metamorphism. Otherwise, an upper limit of 2000–2300 m.y., which is the primary age of detrital zircon populations, can be established. Zircon populations of paragneisses and their anatectic derivatives were separated into size and shape fractions. From morphologic studies and U-Pb isotopic analyses, they were found to be composites of young concordant (318–325 m.y.) and old, highly discordant zircon components, with more than fifty per cent of young crystals in some anatexites. The apparent ages of the composites are 320–750 m.y. The U concentrations of the newly formed crystals can be higher, equal, or lower than those of the inherited zircon component. Some peculiarities in the concordia plot of the zircon data of paragneisses and migmatites (curved pattern; inversion of the generally observed systematics with respect to U concentration, grain size, degree of discordance) are interpreted as the result of polyepisodic disturbances of the inherited crystals in connection with new zircon growth. In the concordia diagram, the data points of the individual zircon grains containing inherited components appear to plot in band or wedgelike areas, and not on lines as the patterns of size fractions of the same zircon populations could pretend. Consequently, ages obtained by extrapolation of the regression curves to the concordia are not necessarily meaningful and require verification by other methods.