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31.
Helmut Wolf 《Journal of Geodesy》1963,37(2):149-163
Ohne Zusammenfassung
Communication présentée à l'Assemblée générale de l'Association Internationale de Géodésie (Helsinki 1960). 相似文献
32.
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34.
Helmut Bock 《Rock Mechanics and Rock Engineering》1971,3(4):225-238
SummaryComputer Simulation of Second Order Faults Faults of the second order can be simulated in the computer with an accuracy hitherto unknown, by using Malina's (1969, 1970) program version of the Finite Element Method. The computations show that stress rearrangements occur with shear movements along the principal fault and with propagation of the fault. These stress rearrangements contribute to the development of new secondary faults. The computed second order faults can be classified according to Chinnery (1966) as shear plane typesA, B, E, andF. Moreover, the computation shows two dominant shear planes which cannot be classified according to Chinnery.
With 11 Figures 相似文献
ZusammenfassungSimulation von Störungen zweiter Ordnung im Computer Störungen zweiter Ordnung lassen sich mit einer bisher noch nicht gekannten Genauigkeit mit Hilfe einer von Malina (1969, 1970) entwickelten Programmversion der Finite-Element-Methode im Computer simulieren. Die Rechnungen zeigen, daß mit einer Scherbewegung entlang der Hauptstörung und dem Weiterreißen der Störung Spannungsumlagerungen einhergehen, die mitbewirken, daß neue sekundäre Störungen entstehen. Die ermittelten Störungen zweiter Ordnung lassen sich nach der Klassifikation von Chinnery (1966) als die ScherflächentypenA, B, E undF einordnen. Darüberhinaus liefert die Rechnung zwei sehr häufig auftretende Scherflächen, die sich nach Chinnery nicht klassifizieren lassen.
RésuméSimulation de failles de deuxième ordre par l'ordinateur Les failles de deuxième ordre peuvent être simulées avec une précision encore jamais atteinte grâce à l'utilisation d'une version d'une programme développé par Malina (1969, 1970) à partir de la méthode des éléments finis. Le calcul montre que, conjointement au cisaillement le long de la faille principale et à la propagation de cette faille, de nouvelles redistributions des contraintes apparaissent. Ces nouvelles redistributions contribuent essentiellement au développement de nouvelles surfaces de failles secondaires. Les failles de deuxième ordre peuvent être classées d'après Chinnery (1966) suivant les catégories de surfaces de cisaillementA, B, E, etF. De plus, le calcul indique fréquemment deux autres types de surfaces de cisaillement n'entrant pas dans la classification de Chinnery.
With 11 Figures 相似文献
35.
Helmut Pichler 《Geoforum》1973,4(2):7-10
The author gives a short introduction into theories of cyclogenesis which are based on instability. The polarfront and baroclinic instability theories are discussed along with the difference between linear and non-linear instability. The author stresses that one may consider cyclogenesis from the point of view of the production of cyclonic vorticity. The terms responsible for the production of vorticity become increasingly important as soon as the horizontal and vertical wind shear as expressed by the Rossby and Richardson numbers reach a critical combination. This critical combination can be reached more easily if heat of condensation is set free than with purely dry-adiabatic processes. Therefore, cyclogenesis is more easily possible in saturated air than in non-saturated air. 相似文献
36.
The Periadriatic Lineament and its possible extension, the Balatonline, on the one hand and the Balcan-Dinaric Lineament and its continuation (?) the Zagreb-line, on the other hand, separate an outer-region, characterized by clastic, terrestrical Upper Carboniferous and Permian strata, from a marine Inner-region. This Inner-region includes the Southern Alps, the Dinarides, and the ?Igoler“-trough. The aforementioned lineaments were not evident during the Lower Paleozoic, whereas in the Upper Paleozoic (after the Variscan orogenese) a clear separation of the two areas can be seen. As a consequence of the overlapping of the marine sequence into the regions north of the Periadriatic lineaments during the Triassic, the contrast between outer- and inner-regions are agained wiped out. For a full understanding of these facts, significant details are still missing. Above all it is important to find a solution for several still unanswered questions: how far the outer region is still a part of the paleomagnetic “Stabile Europe”; how far the metamorphic development within the region of the Balcan Peninsula, the Pannonic Basin and the Karpates can be compared with the ideas (supported by isotopic-geological dates) of the metamorphic development on both sides of the Insubric line and also how far the Dinaric Ophiolite zones are remains of a Paleothetys. Only when these questions are answered will it be possible to insert the Variscan area into the discussion of plate-tectonics within the Neo-European region. 相似文献
37.
It is attempted to determineT, P values for the lowgrade metamorphic facies. From geologic-petrographic observations and from experiments mineralreactions are outlined which characterize the zeolitic-, the glaucophane- and the greenschistfacies, respectively. Only such reactions are considered which are univariant if Pf=Ps; thus aP-T grid can be arrived at. Experimental data on the equilibria of the relevant reactions is taken from the literature and from own experiments. Experimental results are always checked against known field-observations. Contrary to current opinium, we arrive at rather higher temperatures for the beginning of the lowgrade metamorphic facies: Diagenesis. From sedimentation up to slightly below 300° C. Zeolitic facies. From slightly below 300° C up to about 400° C. Greenschistfacies. From about 400° C up to about 550° C. Glaucophaneschistfacies. Under pressures of at least 6–7 kb this facies begins somewhat above 300° C, probably at about 330° C, grading into high-pressure greenschistfacies. 相似文献
38.
Helmut Pichler 《Pure and Applied Geophysics》1964,59(1):185-190
Zusammenfassung In der vorliegenden Arbeit wurde der orographische Einfluss der Alpen auf eine westliche Höhenströmung untersucht. Dabei hat sich herausgestellt, dass bei westlicher Anströmung des Alpenmassivs die Luftpartikelchen nach rechts abgelenkt werden. Durch einen Radiosondenvergleich zwischen Payerne und Zagreb in 500 mb konnte diese von der Theorie her aufgestellte Forderung bekräftigt werden.
Diese Arbeit stellt den Beitrag FRP Alpenwetter Nr. 2/64 eines vom Österreichischen Forschungsrat subventionierten Forschungsvorhabens dar. 相似文献
Summary The author investigates the orographic influence of the chain of the Alps on a westerly upper air stream. The theory shows that air particles are deflected to the right, if they come with a westerly stream of air. A comparison between the 500 mb winds of Payerne (Switzerland) and Zagreb (Yugoslavia) could confirm this theory.
Diese Arbeit stellt den Beitrag FRP Alpenwetter Nr. 2/64 eines vom Österreichischen Forschungsrat subventionierten Forschungsvorhabens dar. 相似文献
39.
Helmut Erlenkeuser 《Earth and Planetary Science Letters》1980,47(3):319-326
Vertical mixing models applied to the radiocarbon age stratigraphy of sediments have to make allowance for the presumably non-vanishing zero-age of the sedimentary particulates freshly arriving at the sediment surface. The appropriate modifications of the simple box model recently presented by Berger and Johnson are outlined. For seven deep-sea cores, zero-age values are found varying between 0.1 and 1.4 kyr. A high zero-age is likely to be indicative for redistribution processes occurring at the sea floor. The box model has been extended to make allowance for a change of sedimentation rate in the depositional interval under study. 相似文献
40.
Leaching and differential recrystallization of metamict zircon under experimental hydrothermal conditions 总被引:14,自引:0,他引:14
Thorsten Geisler Marcus Ulonska Helmut Schleicher Robert T. Pidgeon Wilhelm van Bronswijk 《Contributions to Mineralogy and Petrology》2001,141(1):53-65
We report results of hydrothermal experiments on four alluvial zircons from Sri Lanka, which cover a wide range of radiation damage, at 450 °C and 1.3 kbar for 744 h with 2 M CaCl2 solution as reactive fluid. After the hydrothermal treatment, the most metamict samples show micrometer-thick reaction rims, which surround apparently unreacted zircon, as revealed by cathodoluminescence (CL) and Nomarski differential interference contrast (NDIC) images. These rims have sharp, curved, and transgressive boundaries with unreacted zircon and are, in some cases, spread out along cracks. The thickness of reaction rims increases with increasing cumulated !-dosage of the starting materials. The reaction rims are strongly enriched in Ca (up to 7000 ppm) and a water species and depleted in radiogenic Pb, Zr, and Si, as revealed by electron microprobe analyses. A significant Th loss from the reaction rims was detected in the case of the most metamict sample, whereas U remained in the structure. FT-infrared spectrometry and X-ray diffraction measurements revealed that the bulk run products were recrystallized. Using micro-Raman spectrometry, we were able to demonstrate that differential recrystallization took place. The reaction rims are strongly recrystallized, whereas the unreacted grain interiors underwent only minor recrystallization. Recrystallization of the rims is accompanied by an enhancement of the integral CL intensity. It is suggested that recrystallization in the reaction rims was catalyzed by water infiltration and ion exchange and prevented significant congruent zircon dissolution under the given experimental conditions. Previous zircon studies have shown that (1) a transgressive morphology, (2) a reduced Th-U ratio, and (3) an enhanced CL emission are also characteristics of rims in zircons from high-grade metamorphic rocks. Based on these similarities between natural and experimentally produced rims, it is suggested that leaching-catalyzed recrystallization is an important alteration process in zircon under wet geological conditions and can account for many complex core-rim structures found in natural zircons. Furthermore, the strong enrichment of Ca in the reaction rims supports previous assumptions that high Ca concentrations in natural zircons are of secondary origin. It is suggested that lower U-Pb concordia intercept ages obtained from single-phase zircons with high Ca contents date a leaching event. 相似文献