Evidence for sea-floor spreading in the Cayman Trough     

T.L. Holcombe  P.R. Vogt  J.E. Matthews  R.R. Murchison 《Earth and Planetary Science Letters》1973,20(3):357-371

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Die Glaukophangesteine,ihre stofflichen Äquivalente und Uniwandlungsprodukte in Nordcalabrien (Süditalien)     

Dr. Christoph Hoffmann 《Contributions to Mineralogy and Petrology》1970,27(4):283-320

In the southern Apennin (= northern part of the region dealt with) and the Coasta Chain (= southern part) there are metabasalts wich are classified in the northern part as:

1. Glaucophane rocks of the albite-lawsonite-glaucophane-subfacies with the assemblage glaucophane + pumpellyite + lawsonite ±albite ±aragonite ±muscovite (7 rock analyses, 8 mineral analyses). These rocks are conceived as relics of an older burial metamorphism.
2. Rocks with pumpellyite and chlorite or also chlorite alone, that are interpreted as reaction rims between the metastable glaucophane rocks and the country rock (phyllites, quartzites). The assemblages pumpellyite + chlorite and chlorite alone are to be found (2 rock analyses and 2 mineral analyses).
3. Rocks with lawsonite and/or epidote belong to the same mineral facies as the country rock: a facies similar to the greenschist facies (called “lawsonite-albite-chlorite-subfacies”) which is characterized by the assemblages lawsonite + albite + chlorite ±calcite and also epidote ±lawsonite + albite + chlorite ± muscovite. These types are attributed to a younger dynamo-metamorphism (2 rock analyses).

In the southern part, the metabasalts can be found only as rocks with epidote and/or lawsonite, a metamorphism with more than one event cannot be proved petrologically (3 rock analyses). Equations of the observed mineral reactions are given. The transitions of one facies into another are represented in the pseudo-quaternary system Al₂O₃-CaO-Na₂O · Al₂O₃-2 Fe₂O₃ + FeO + MnO + MgO-(H₂O). The pressure-temperature conditions are estimated on the basis of published experimental data (300° C and 6–7 kb for the glaucophane rocks; 400° C and about 6 kb for the rocks with lawsonite and/or epidote) and are compared with geologic facts.  相似文献   

Deutung von Eigenfrequenzen in Zweikreiselkompaßsystemen     

Dr. Peter Christoph 《Ocean Dynamics》1969,22(2):49-56

Zusammenfassung Der Versuch, die experimentell durch Messung an handelsüblichen Zweikreiselkompaßsystemen festgestellten Eigenfrequenzen mit theoretisch berechneten Werten in Übereinstimmung zu bringen, indem die System-Trägheitsmomente Berücksichtigung finden, bringt keinen Erfolg. Erst die zusätzliche Beachtung der Elastizität der Kreiselachsen bringt eine befriedigende Übereinstimmung zwischen Messung und Theorie.

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Interpretation of the natural frequencies in double-gyro compass systems

Summary An attempt to harmonize the natural frequencies measured at commercial double-gyro compass systems with theoretically computed values by taking account of the moments of inertia of the systems proved unsuccessful. A satisfactory agreement between measurement and theory is reached only after additionally taking into account the elasticity of the gyro axes.

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Interprétation des fréquences propres dans le système des compas à deux gyroscopes

Résumé Quand on essaye par des mesures expérimentales, de mettre en accord les fréquences propres constatées avec leurs valeurs calculées théoriquement dans les systèmes de compas à deux gyroscopes d'usage courant, en tenant compte des moments d'inertie des systèmes, on n'obtient aucun résultat. C'est seulement en prenant de plus en considération l'élasticité des axes des gyroscopes qu'on obtient un accord satisfaisant entre la mesure et la théorie.

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Kyanite-eclogite to amphibolite fades evolution of hydrous mafic and pelitic rocks,Adula nappe,Central Alps     

Christoph A. Heinrich 《Contributions to Mineralogy and Petrology》1982,81(1):30-38

In the southern Adula nappe (Central Alps), two stages of regional metamorphism have affected mafic and pelitic rocks. Earlier eclogite facies with a regional zonation from glaucophane eclogites to kyanite-hornblende eclogites was followed by a Tertiary overprint which varied from greenschist to high-grade amphibolite facies. Despite a common metamorphic history, contrasting equilibration conditions are often recorded by high-pressure mafic eclogite and adjacent predominantly lower-pressure pelite assemblages. This pressure contrast may be explained by different overprinting rates of the two bulk compositions during unloading. The rates are controlled by a mechanism in which dehydrating metapelites provide the H₂O required for simultaneous overprinting of enclosed mafic eclogites by hydration.Quantitative mass balance modelling based on corona textures is used to show that overprinting of metapelites during unloading involved dehydration reactions. The relatively rapid rate of dehydration reactions led to nearly complete reequilibration of metapelites to amphibolite facies assemblages.After the formation during high-pressure metamorphism of mafic eclogites, later lower-pressure reequilibration by hydration to amphibolites was slow, and therefore incomplete, because it depended on large scale transport of H₂O from adjacent, dehydrating metapelites.The facies contrast observed between rocks of different bulk composition is thus a consequence of the general tendency of metamorphic rocks to retain the most dehydrated assemblage as the final recorded state.  相似文献   

Representation of orbital element variations and force function with respect to various reference systems     

Christoph Reigber 《Journal of Geodesy》1981,55(2):111-131

Some questions connected with the analysis of orbital element perturbations and the force field formulation for precise orbit determination are discussed. This includes a simple derivation of the kinematic effect for expressing the Lagrange planetary equations with respect to various reference frames and the representation of the Earth gravitational potential and apparent forces in these systems. Some numerical results are given.  相似文献   

Basement control on oblique thrust sheet evolution: seismic imaging of the active deformation front of the Central Andes in Bolivia     

Ralph Hinsch  Charlotte M. Krawczyk  Christoph Gaedicke  Raul Giraudo  Daniel Demuro 《Tectonophysics》2002,355(1-4)

In the area of the Bolivian Orocline, we examine the deformation pattern associated with the active development of a new thrust sheet. A dense grid of reprocessed 2-D seismic lines from hydrocarbon exploration industry is interpreted and a 3-D simplified structural and kinematic model is deduced. In the Boomerang Hills, onlapping Paleozoic and foredeep sediments are detached from the underlying S-dipping basement. They are thrust northeastwards by less than 2 km. Two zones can be differentiated along the Andean deformation front: (1) a W–E to NW–SE striking frontal segment of predominantly orthogonal shortening, comprising a thrust and anticline system; (2) a WSW–ENE striking lateral zone of oblique shortening within a complex system of thin-skinned strike–slip faults and minor folds. The deformation front always follows a pronounced edge in the topography of the top basement surface close to the boundary of the Paleozoic basin. The observed deformation pattern indicates intensified strain partitioning caused by the interaction of contraction direction and basement topography, which provides a near oblique ramp for the onlapping wedge of sediments. The SW–NE thrusting direction is divided into orthogonal and tangential components. These are accommodated by convergent and strike–slip structures, respectively, which sole into a common detachment horizon. The structural evolution of the new thrust sheet in the Bolivian Orocline is primarily controlled by the paleorelief of the Brazilian Shield because: (1) the shape of the basement affects the taper of the thrust wedge and localizes the deformation front and (2) small asperities in/close to the top of the basement promote fault localization. The coincidence of a relatively high basement position and a structural high of the Eastern Cordillera leads to the conclusion that the shape of the Brazilian Shield also controls the structural evolution of the pronounced eastern border of the Bolivian Orocline.  相似文献   

Shallow water wave modelling with nonlinear dissipation     

Christoph Schneggenburger  Heinz Günther  Wolfgang Rosenthal 《Ocean Dynamics》1997,49(2-3):431-444

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Tracer experiment with sulfur hexafluoride to quantify the vertical transport in a meromictic pit lake     

Christoph von Rohden  Johann Ilmberger 《Aquatic Sciences - Research Across Boundaries》2001,63(4):417-431

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KGI-XGIS SUPPORTING DECISION MAKING WITH KNOWLEDGE-BASED TECHNIQUES     

Steffen Vogt 《地球空间信息科学学报》2001,4(2):40-46

1　ＩｎｔｒｏｄｕｃｔｉｏｎＫｉｎｇＧｅｏｒｇｅＩｓｌａｎｄ (ＳｏｕｔｈＳｈｅｔｌａｎｄＩｓｌａｎｄｓ,Ａｎｔａｒｃｔｉｃａ)ｉｓｏｎｅｏｆｔｈｅｍｏｓｔｄｅｎｓｅｌｙｐｏｐｕｌａｔｅｄａｒ ｅａｓｉｎＡｎｔａｒｃｔｉｃａ .Ｐｅｒｍａｎｅｎｔｓｔａｔｉｏｎｓｏｆｎｉｎｅｄｉｆｆｅｒ ｅｎｔｎａｔｉｏｎｓａｎｄａｎａｉｒｓｔｒｉｐｓｕｉｔａｂｌｅｆｏｒｈｕｇｅａｉｒ ｃｒａｆｔｓａｒｅｌｏｃａｔｅｄｏｎｉｔｓｉｃｅｆｒｅｅａｒｅａｓ.Ｔｈｅｓｅａｒｅａｓｃｏｍｐｒｉｓｅｌｅｓｓｔｈａｎ 5%ｏｆｔｈｅｉｓｌ…  相似文献   

The HartX-synthesis: An experimental approach to water and carbon exchange of a Scots pine plantation     

Ch. Bernhofer  L. W. Gay  A. Granier  U. Joss  A. Kessler  B. Köstner  R. Siegwolf  J. D. Tenhunen  R. Vogt 《Theoretical and Applied Climatology》1996,53(1-3):173-183

Summary In May 1992 during the interdisciplinary measurement campaign HartX (Hartheim eXperiment), several independent estimates of stand water vapor flux were compared at a 12-m high Scots pine (Pinus silvestris) plantation on a flat fluvial terrace of the Rhine close to Freiburg, Germany. Weather during the HartX period was characterized by ten consecutive clear days with exceptionally high input of available energy for this time of year and with a slowly shifting diurnal pattern in atmospheric variables like vapor pressure deficit. Methods utilized to quantify components of stand water flux included porometry measurements on understory graminoid leaves and on pine needles and three different techniques for determining individual tree xylem sap flow. Micrometeorological methods included eddy covariance and eddy covariance energy balance techniques with six independent systems on two towers separated by 40 m. Additionally, Bowen ratio energy balance estimates of water flux were conducted and measurements of the gradients in water vapor, CO₂, and trace gases within and above the stand were carried out with an additional, portable 30 m high telescoping mast.Biologically-based estimates of overstory transpiration were obtained by up-scaling tree sap flow rates to stand level via cumulative sapwood area. Tree transpiration contributed between 2.2 and 2.6 mm/day to ET for a tree leaf area index (LAI) of 2.8. The pine stand had an understory dominated by sedge and grass species with overall average LAI of 1.5. Mechanistic canopy gas exchange models that quantify both water vapor and CO₂ exchange were applied to both understory and tree needle ecosystem compartments. Thus, the transpiration by graminoid species was estimated at approximately 20% of total stand ET. The modelled estimates for understory contribution to stand water flux compared well with micrometeorologically-based determinations. Maximum carbon gain was estimated from the canopy models at approximately 425 mmol/(m²day) for the tree needles and at 100 mmol/(m²day) for the understory. Carbon gain was suggested by the modelling analysis to remain relatively constant during the HartX period, while water use efficiency in carbon fixation increased with decreasing vapor pressure deficit. Biologically- and micrometeorologically-based estimates of stand water flux showed good general agreement with variation of up to 20% that reflects both errors due to the inherent assumptions associated with different methods as well as natural spatial variability in fluxes. The various methods support a reliable estimate of average ET from this homogeneous canopy during HartX of about 2.6 mm/day (a maximum of about 3.1 mm/day) with an insignificant decreasing trend in correlation with decreasing vapor pressure deficit and possibly soil moisture.Findings during HartX were embedded in local scale heterogeneity with greater roughness over the forest and much higher ET over the surrounding agricultural fields which results in weak but clearly existant circulation patterns. A variety of measurements were continued after the HartX campaign. They allow us to extend our findings for six months with changing environmental conditions, including shortage of soil moisture. Hydrological estimates of soil water extractions and micrometeorological estimates of ET by the one-propeller eddy covariance (OPEC) system were in very good agreement, supporting the use of this robust eddy covariance energy balance technique for long-term monitoring.With 5 Figures  相似文献