A natural analogue of high pH cement pore waters from the Maqarin area of northern Jordan. I: introduction to the site

The highly alkaline springs of the Maqarin area of northern Jordan are currently under examination as part of an international project testing the models used to analyse the safety of repositories for low and intermediate level radioactive waste (L/ILW). The Maqarin area contains a rock-groundwater system which is an ideal natural analogue of a concrete-filled L/ILW repository emplaced in a sedimentary host rock. The high pH (12.5) groundwaters at this site are the product of interaction with naturally occurring cement minerals and not of the alteration of ultramafic minerals. Stable isotope data for the hyperalkaline groundwaters lie below both the local meteoric water line and the eastern Mediterranean water line. At least part of the shift appears to be the result of groundwater interaction with the cement minerals. This paper introduces the site of the natural analogue study and, in presenting novel data on the chemistry and stable isotopic signature of the groundwater, provides background information which is used in a companion paper (Alexander et al., 1992) on testing the predictive capabilities of geochemical thermodynamic codes (and their associated databases) which will be utilised as part of the safety assessment of a L/ILW repository.     

Der Lauf der Ruhr als Modell einer heterogenen Stromlinie

Ohne Zusammenfassung     

Ernst Weinschenk (1865–1921) a pioneer of microscopy and petrography in Munich (Southern Germany)

Ernst Weinschenk was an excellent teacher at the High School of Technology from 1897 till his death 1921, and at the university in Munich from 1900. His studies of the mineralogy of meteorites and the contact-metamorphic mineralization in the eastern and western Alps and southern Tyrol made him widely known early-on. He successfully determined many new minerals with the aid of the polarizing microscope and the use of mineral and thin rock sections. He attributed the genesis of the sulfidic ore deposit Silberberg at Bodenmais (northern Bavarian Forest) and the graphite deposits near Passau (Lower Bavaria) to the exhalative output of sulphur and carbon during the granite orogenesis (Weinschenk 1914).     

Contrasting sediment flux in Val Lumnezia (Graubünden, Eastern Swiss Alps), and implications for landscape development

This paper presents qualitative estimates of sediment discharge from opposite valley flanks in the S–N-oriented Val Lumnezia, eastern Swiss Alps, and relates inferred differences in sediment flux to the litho-tectonic architecture of bedrock. The valley flank on the western side hosts the deep-seated Lumnezia landslide where an area of ca. 30 km² has experienced slip rates of several centimetres per year, potentially resulting in high sediment discharge to the trunk stream (i.e. the Glogn River). High slip rates have resulted in topographic changes that are detectable on aerial photographs and measurable with geodetic tools. In contrast, a network of tributary channels dissects the valley flank on the eastern side. There, an area of approximately 18 km² corresponding to < 30% of the surface has experienced a change in the landscape mainly by rock avalanche and rock fall, and the magnitudes of changes are below the calibration limit of digital photogrammetry. We thus infer lower magnitudes of sediment discharge on the eastern tributaries than on the western valley side, where landsliding has been the predominant erosional process. These differences are interpreted to be controlled by the dip-slope situation of bedrock on the western side that favours down-slope slip of material. Morphometric investigations reveal that the western valley side is characterized by a low topographic roughness because this valley flank has not been dissected by a channel network. It appears that high sediment discharge of the Lumnezia landslide has inhibited the establishment of a stable channel network and has largely controlled the overall evolution of the landscape. This contrasts to the general notion that channelized processes exert the first-order control on landscape evolution and formation of relief and needs to be considered in future studies about landscape architecture, drainage network and sediment discharge.     

Computational validation of static and dynamic plate load testing

In this paper, the static load plate test and the dynamic load plate test by means of the light falling weight device are assessed utilizing numerical simulations. Simplified computational models of the tested subsoil and of the testing devices are developed, which capture the main effects of both the static and the dynamic load plate test. In extensive parametric studies, the impact of various subsoil conditions on the test results and several sources of error are evaluated and discussed. Computational test results of the static load plate test and of the dynamic load plate test are set in contrast to an effort to demonstrate the differences and the common features of the outcomes.     

Kinematics of crustal stacking and dispersion in the south-eastern Bohemian Massif

The south-eastern Bohemian Massif consolidated during the Late Variscan orogeny by the oblique collision of two continental crustal blocks after closure of an oceanic realm. One microcontinent comprises portions which are now distributed among Moravian and Moldanubian units and which are characterized by Late Proterozoic tectonothermal events, especially by granitoid intrusions. The other microcontinent includes the Gföhl gneiss and granulites (Gföhl nappe) of probable Early Palaeozoic protolith ages. Both continental blocks are separated by an ophiolite-like assemblage, which is preserved in portions of the Raabs unit.Oblique crustal stacking is accompanied by north-eastward propagation of nappes in a dextral transpressive regime. Exhumation of previously thickened crust is achieved by equally oriented bulk extension but partitioned in distinct displacement paths. Coeval stacking and extension at different crustal levels is suggested.Correspondence to: H. Fritz