Grenzen quantitativer Untersuchungen bei tektonischen Experimenten

Quantitative experimental and theoretical investigations, except basic research, should focus only to such parameters which can be measured in the field. This is shown by three examples.

1. A model of a discontinuum composed of particles, between which friction occurs during shear is presented. Even at simple shear external and internal stresses are in equilibrium; no rigid body rotation occurs. The theory is examinated experimentally.
2. In deformation experiments with clay and sand a development of anisotropy is observed, which can cause shear fractures. The orientation of the normal stress directions can be discovered from the shear sets, their angular distribution, and the rotation of the individual blocks.
3. Most folds can be traced back to the following three types, a) Similar folds, b) concentric folds, and c) box folds. b) and c) occur only near the surface and near shear planes, as shown by experiments and field observations. In all other cases the more energy-consuming similar folds are formed. Kink bands are presumably transitional between folds and shear fractures.

     

Über die Verteilung und Neubildung der nichtkarbonatischen Mineralkomponenten der Oberkreide aus der Umgebung von Hannover

Comparative investigations were made on the non-carbonate components of calcareous sediments of the upper chalk formation of the Hanover region.The mineral composition of the residues insoluble in 0.5 n HC1 has first been determined optically and by X-ray photographs and described. The quantitative analysis of the components contained was effected by microscopic counting using the phase contrast method up to the grain size of 2 u, and for the clay fractions proper by X-ray phase analyses.In addition to the minor components (feldspars, biotite, pyrite, marcasite, glauconite, heavy minerals and mikro-fossils) the residues contain quartz, muscovite, illite, montmorillonite and kaolinite.The calcareous sediments of the upper senon formation are specially characterized by the occurrence of authigenic heulandite crystals which could be analysed and described here for the first time. Moreover secondary crystallization of quartz, turmaline and albite could be observed in all the samples analysed.     

Zur petrologischen und tektonischen Analyse des Fichtelgebirges

Zusammenfassung Es wird über auffällige petrographische und tektonische Erscheinungen an den Gneisen des Fichtelgebirges berichtet. Die Gneise haben hier alle eine epizonale Dislokationsmetamorphose erfahren, wie sie in den Mylonitgneisen von Goldkronach heute vorliegt. Die epizonale Fazies wurde in den Wunsiedeler Kerngneisen in der Kontakthaube des variscischen Granites katazonal (bis mesozonal) umgeprägt. Eine großartige, an alpine Beispiele erinnernde Tektonik wird durch Gesteinsverknetungen sichtbar. Eine jüngere, 35 km lange Blattverschiebung wird an der gleichsinnigen Verlagerung von Münchberger Gneis (Bernecker Gneiskeil), Paläozoikum, der Achsen der Magmatite und von drei Marmorzügen nachgewiesen.     

Shock effects in MgAl2O4-spinel

Shock recovery experiments on synthetic MgAl₂O₄-spinel samples in the pressure range 25.5 to 50.5 GPa have been performed in order to examine the effects of shock waves on this material. The shocked samples were subsequently studied in the transmission electron microscope. All samples showed shock-induced dislocations with the Burgers vector 1/2 〈110〉 and twin lamellae of the twin-law {111}. In addition, samples, which had experienced the higher pressures, showed lamellar areas of a crystalline phase that we have not yet been able fully to characterize. It is probably not ε-MgAl₂O₄.     

Lower Rotliegend fluvio-lacustrine sequences in the Saar-Nahe Basin

The Rotliegend beds of the middle of the Kusel Group to the middle of the Lebach Group in the Saar-Nahe Basin are characterized by sedimentary sequences which developed in streams, deltas, and lakes. The stream sequences consisting of cross-stratified sandstone units are attributed to braided fluvial environment. The lake-delta sequences usually show gradual transition from lacustrine mudstones to delta-front cross-stratified sandstones and to floodbasin, crevasse and overbank sandstones and mudstones. Loaded high-intensity flows occasionally result in deformation- and erosion-structures. Low-energy lacustrine sedimentation is evident from paper-shales and massive mudstones. The mudstones alternate with cross-laminated sandstones where influenced by terrigenous influx.     

Solar-Blind Diamond Detectors for Lyra, the Solar VUV Radiometer on Board Proba II

Fabrication, packaging and experimental results on the calibration of metal-semiconductor-metal (MSM) photodetectors made on diamond are reported. LYRA (Lyman- RAdiometer onboard PROBA-2) will use diamond detectors for the first time in space for a solar physics instrument. A set of measurement campaigns was designed to obtain the XUV-to-VIS responsivity of the devices and other characterizations. The measurements of responsivity in EUV and VUV spectral ranges (40–240 nm) have been carried out by the Physkalisch-Technische Bundesanstalt (PTB) in Germany at the electron storage ring BESSY II. The longer wavelength range from 210 to 1127 nm was measured with monochromatic light by using a Xe-lamp at IMO-IMOMEC. The diamond detectors exhibit a photoresponse which lie in the 35–65 mA/W range at 200 nm (corresponding to an external quantum efficiency of 20–40%) and indicate a visible rejection ratio (200–500 nm) higher than four orders of magnitude.     

Modelling Two-Phase Incompressible Flow in Porous Media Using Mixed Hybrid and Discontinuous Finite Elements

In this paper, we present a numerical model for simulating two-phase (oil–water and air–water) incompressible and immiscible flow in porous media. The mathematical model which is based on a fractional flow formulation is formed of two nonlinear partial differential equations: a mean pressure equation and a water saturation equation. These two equations can be solved in a sequential manner. Two numerical methods are used to discretize the equations of the two-phase flow model: mixed hybrid finite elements are used to treat the pressure equation, h-based Richards' equation and the diffusion term in the saturation equation, the advection term in the saturation equation is treated with the discontinuous finite elements. We propose a better way to calculate the nonlinear coefficients contained in our equations on each element of the discretized domain. In heterogeneous porous media, the saturation becomes discontinuous at the interface between two porous media. We show in this paper how to use the capillary pressure–saturation relationship in order to handle the saturation jump in the mixed hybrid finite element method. The two-phase flow simulator is verified against analytical solutions for some flow problems treated by other authors.     

The Cenozoic Lower Rhine Basin – rifting, sedimentation, and cyclic stratigraphy

In the Cenozoic, the Lower Rhine Basin formed as a rift at the southeastern terminus of the Dutch German Central Graben, while the Rhenish Massif was uplifted. The study focusses on the marginal marine and fluvial fill of the Lower Rhine Basin. A basin model is developed. Support for this study was given by extensive industry outcrop and well data, by new stratigraphical and sedimentological observations. The ingression and subsequent regression of the Cenozoic North Sea is analysed using the concept of base level cyclicity. As the geohistory of the basin was complex, a subsidence curve is constructed. Furthermore, an attempt is made to trace the simultaneous uplift of the Rhenish Massif.