Results of a semi-implicit two-step method for the simulation of markedly nonlinear flow in coastal seas   总被引：1，自引：0，他引：1  

Kurt C. Duwe  Regina R. Hewer  Jan O. Backhaus 《Continental Shelf Research》1982,2(4):255-274

Results of a numerical method for the simulation of nonlinear flow in coastal seas are presented. The method is based on a neutral semi-implicit scheme which is modified into a stability-enhancing two-step algorithm. By means of this method the simulation of highly nonlinear flow patterns is possible in a stable and economic way. Three examples of models of different North Sea coastal regions are discussed under certain aspects to demonstrate the reliability of the method.  相似文献   

Hydraulic properties of the crystalline basement   总被引：1，自引：1，他引：1  

Ingrid Stober  Kurt Bucher 《Hydrogeology Journal》2007,15(2):213-224

Hydraulic tests in boreholes, up to 4.5 km deep, drilled into continental crystalline basement revealed hydraulic conductivity (K) values that range over nine log-units from 10⁻¹³−10⁻⁴ m s⁻¹. However, K values for fractured basement to about 1 km depth are typically restricted to the range from 10⁻⁸ to 10⁻⁶ m s⁻¹. New data from an extended injection test at the KTB research site (part of the Continental Deep Drilling Program in Germany) at 4 km depth provide K=5 10⁻⁸ m s⁻¹. The summarized K-data show a very strong dependence on lithology and on the local deformation history of a particular area. In highly fractured regions, granite tends to be more pervious than gneiss. The fracture porosity is generally saturated with Na–Cl or Ca–Na–Cl type waters with salinities ranging from <1 to >100 g L⁻¹. The basement permeability is well within the conditions for advective fluid and heat transport. Consequently, fluid pressure is hydrostatic and a Darcy flow mechanism is possible to a great depth. Topography-related hydraulic gradients in moderately conductive basement may result in characteristic advective flow rates of up to 100 L a⁻¹ m⁻² and lead to significant advective heat and solute transfer in the upper brittle crust. An erratum to this article can be found at  相似文献   

Compaction localization in the Earth and the laboratory: state of the research and research directions   总被引：1，自引：1，他引：1  

David Holcomb  John W. Rudnicki  Kathleen A. Issen  Kurt Sternlof 《Acta Geotechnica》2007,2(1):1-15

Localized compaction in porous rocks is a recently recognized phenomenon that has been shown to reduce permeability dramatically. Consequently, the phenomenon is relevant to a variety of technologies involving fluid injection or withdrawal. This article summarizes current understanding of localized compaction and impediments to further progress. The article is based on discussions at a small workshop on localized compaction sponsored by the Office of Science, U. S. Department of Energy.  相似文献   

Corrigendum to “Global ice volumes at the Last Glacial Maximum and early Lateglacial” [Earth Planet. Sci. Lett. 181 (2000) 513–527]     

Kurt Lambeck  Yusuke Yokoyama  Paul Johnston  Anthony Purcell 《Earth and Planetary Science Letters》2001,190(3-4):275

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Microbial–silica interactions in Icelandic hot spring sinter: possible analogues for some Precambrian siliceous stromatolites     

Kurt O. Konhauser  Vernon R. Phoenix  Simon H. Bottrell  David G. Adams  & Ian M. Head 《Sedimentology》2001,48(2):415-433

Silicified deposits, such as sinters, occur in several modern geothermal environments, but the mechanisms of silicification (and crucially the role of microorganisms in their construction) are still largely unresolved. Detailed examination of siliceous sinter, in particular sections of microstromatolites growing at the Krisuvik hot spring, Iceland, reveals that biomineralization contributes a major component to the overall structure, with approximately half the sinter thickness attributed to silicified microorganisms. Almost all microorganisms observed under the scanning electron microscope (SEM) are mineralized, with epicellular silica ranging in thickness from < 5 μm coatings on individual cells, to regions where entire colonies are cemented together in an amorphous silica matrix tens of micrometres thick. Within the overall profile, there appears to be two very distinct types of laminae that alternate repeatedly throughout the microstromatolite: ‘microbial’ layers are predominantly consisting of filamentous, intact, vertically aligned, biomineralized cyanobacteria, identified as Calothrix and Fischerella sp.; and weakly laminated silica layers which appear to be devoid of any microbial component. The microbial layers commonly have a sharply defined base, overlying the weakly laminated silica, and a gradational upper surface merging into the weakly laminated silica. These cyclic laminations are probably explained by variations in microbial activity. Active growth during spring/summer allows the microorganisms to keep pace with silicification, with the cell surfaces facilitating silicification, while during their natural slow growth phase in the dark autumn/winter months silicification exceeds the bacteria’s ability to compensate (i.e. grow upwards). At this stage, the microbial colony is probably not essential to microstromatolite formation, with silicification presumably occurring abiogenically. When conditions once again become favourable for growth, recolonization of the solid silica surface by free‐living bacteria occurs: cell motility is not responsible for the laminations. We have also observed that microbial populations within the microstromatolite, some several mm in depth, appear viable, i.e. they still have their pigmentation, the trichomes are not collapsed, cell walls are unbroken, cytoplasm is still present and they proved culturable. This suggests that the bulk of silicification occurred rapidly, probably while the cells were still alive. Surprisingly, however, measurements of light transmittance through sections of the microstromatolite revealed that photosynthetically active light (PAL) only transmitted through the uppermost 2 mm. Therefore the ‘deeper’ microbial populations must have either: (i) altered their metabolic pathways; (ii) become metabolically inactive; or (iii) the deeper populations may be dominated by different microbial assemblages from that of the surface. From these collective observations, it now seems unequivocal that microstromatolite formation is intimately linked to microbial activity and that the sinter fabric results from a combination of biomineralization, cell growth and recolonization. Furthermore, the similarities in morphology and microbial component to some Precambrian stromatolites, preserved in primary chert, suggests that we may be witnessing contemporaneous biomineralization processes and growth patterns analogous to those of the early Earth.  相似文献   

Tectonics and sedimentation in the Fohnsdorf-Seckau Basin (Miocene, Austria): from a pull-apart basin to a half-graben     

Philipp Strauss  Michael Wagreich  Kurt Decker  Reinhard F. Sachsenhofer 《International Journal of Earth Sciences》2001,90(3):549-559

The Miocene intramontane Fohnsdorf-Seckau Basin is situated at the junction of the sinistral Mur-Mürz-fault system and the dextral Pöls-Lavanttal fault system. The basin comprises a 2,400-m-thick coal-bearing fluviodeltaic-lacustrine succession (Lower to Middle Miocene, Upper Karpatian?/Lower Badenian) which is overlain by a 1,000-m-thick alluvio-deltaic conglomeratic succession (Apfelberg Formation, ?Middle/Upper Badenian) in the south. A three-stage model for the basin evolution has been reconstructed from structural analysis and basin fill geometries. During a first pull-apart phase, subsidence occurred along ENE-trending, sinistral strike-slip faults of the Mur-Mürz fault system and NE-SW to N-S-trending normal faults, forming a composite pull-apart basin between overstepping en-echelon strike-slip faults. The Seckau and Fohnsdorf sub-basins are considered as two adjacent pull-aparts which merged into one basin. During the second phase, N-S to NNW-SSE extension and normal faulting along the southern basin margin fault formed a half-graben, filled by wedge-shaped alluvial strata (Apfelberg Formation). During the third phase, after the end of basin sedimentation, the dextral Pöls-Lavanttal fault system reshaped the western basin margin into a positive flower structure.  相似文献   

Röntgenographische Gefügeanalyse mit dem Texturgoniometer am Beispiel von Quarziten aus kaledonischen Überschiebungszonen     

Dr. Kurt v. Gehlen  Dr. Gerhard Voll 《International Journal of Earth Sciences》1962,51(2):440-450

Zusammenfassung Quantitative Gefügediagramme können röntgenographisch mit einem Zählrohr-Textur-Goniometer gemessen werden. Diese Methode kommt besonders in Frage bei sehr feinkörnigen Gesteinen oder aber dann, wenn etwa bei einachsigen Mineralen auch die Regelung anderer Gitterrichtungen außer der c-Achsen-Richtung interessiert. Das beim Quarz anzuwendende Verfahren wird behandelt und gezeigt, wie man hier im Einzelfall Prismenregelungen nachweisen kann. Als praktische Beispiele werden Quarzitgefüge mit Prismenregelung aus kaledonischen Überschiebungszonen Schottlands und Norwegens abgebildet und ihre Entstehung diskutiert. Die Messungen scheinen darauf hinzuweisen, daß beim Quarz bevorzugt Translation mit (11¯20) als Gleitfläche und c als Gleitgerade maßgebend war.  相似文献   

Die Kernfragen der Sonnenstrahlung in gedrängter Darstellung     

Kurt Wegener 《Pure and Applied Geophysics》1959,43(1):278-284

Summary The development of the law of radiation, and his consequences, shortly exposed.

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Résumé La loi de la radiation, developpement et consequences.

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Die röntgenographische und optische Gefügeanalyse von Erzen,insbesondere mit dem Zählrohr-Texturgoniometer     

Dr. Kurt v. Gehlen 《Contributions to Mineralogy and Petrology》1960,7(5):340-388

Quantitative determinations of preferred orientation of opaque minerals have been made only in a few cases by measuring cleavage faces (galena,D. Schachner-Korn). In this paper several methods are investigated critically which are likely to allow the determination of pole figures of ore minerals in a reasonable time. In the first part the special difficulties are discussed which occur in measurements of preferred orientation with X-ray pole figure goniometers (reflection method byL. G. Schulz) when the specimen consists of more than one mineral, when the mineral investigated is coarse-grained, and when the specimen is small. A critical discussion of instrumental errors is included. This method can now also be applied to the determination of preferred orientation in rocks, ceramic materials, etc. In the second part optical methods are given which include the construction of pole figures from measurements of bireflection and polarization figures of uniaxial minerals in reflected light. Examples of pole figures of pyrrhotite, hematite, pyrite, sphalerite, and chromite are given.

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Der Naturwissenschaftlichen Fakultät der Friedrich-Alexander-Universität Erlangen als Habilitationsschrift vorgelegt.  相似文献   

Computation of 5-day temperature normals in western Europe and the Mediterranean area     

Kurt Bender  Ulrich Chorus  Raymond Nybro  Robert Sanderson  Ingrid Weiss 《Pure and Applied Geophysics》1957,38(1):265-285

Summary UsingCraddock's method of representing the annual temperature variation by a two-term harmonic form fitted to monthly means, the harmonic coefficients of 63 stations in western Europe and around the Mediterranean Sea, as well as the 5-day normals for 24 Mediterranean stations, were computed and tabulated. In addition, some of the harmonic coefficients were charted and isoplethed, showing very distinctly the influence of continentality and topography. These charts, together withCraddock's charts for northern and northwestern Europe, provide fairly complete coverage of Europe and the Mediterranean area.This paper was prepared in the offices of the Technical Support Division of the 2d Weather Wing, United States Air Force, as a matter of routine business. The information contained herein was presented at the 5th Meeting of the Italian Society of Geophysics and Meteorology by Dr.Ingrid Weiss (Genoa: 23–25 April 1957). Since the paper is of general interest to all meteorologists of the Mediterranean area, it is published here with the permission of the originating agency as «Mémoire No. 3 du Centre International de Recherches sur la Météorologie de la Méditerranée (CIRMM)».  相似文献