Deep saltwater in Chalk of North-West Europe: origin, interface characteristics and development over geological time

High-concentration saltwaters occur in many places in the regional Chalk aquifers of North-West Europe; to investigate deep occurrences, profiles of interstitial porewater chemistry have been studied from three 250–450m deep cores drilled in the eastern parts of Zealand, Denmark. At the studied location, saline water in the Chalk resides at depths from 40 to 80m and salinity increases with depth. Concentrations of chloride up to ca. 30,000ppm have been observed at depths of 400m. Measured vertical hydraulic heads in open boreholes suggest that advective groundwater flow is now restricted in deeper parts of the Chalk formation and diffusive transport is thus the predominant transport mechanism. Laboratory-measured porosity and effective diffusion coefficients were used as input to a numerical 1D diffusion model of the interface between freshwater in an upper, fractured aquifer and modified connate formation water below. The model satisfactorily simulated the observed chloride and δ¹⁸O profiles. The diffusive refreshening of the Chalk formation has been going on for about 0.9 million years. The connate water in the Chalk of parts of the sedimentary basin seems to have been modified by transport of saltwater from underlying Mesozoic and Paleozoic sediments during compaction, which presumably ceased around 4 million years ago.     

Isotopic composition of a large photosymbiotic foraminifer: Evidence for hypersaline environments across the Great Australian Bight during the late Pleistocene

Analysis of carbon and oxygen isotopic compositions of large benthic foraminifera tests (Marginopora vertebralis) that lived in the Great Australian Bight during the late Pleistocene, reveal that the tests are enriched by 1 to 3‰ in both ¹⁸O and ¹³C relative to modern specimens from the same region. The intolerance of M. vertebralis for cool waters negates lower ocean water temperature as an explanation for such high δ¹⁸O values. The oxygen isotopic compositions are thus interpreted to reflect tests secreted in hypersaline waters of up to 56 ppt salinity, concentrated from seawater by evaporation. M. vertebralis thrives today in waters of similar salinity at Shark Bay, Western Australia. The Pleistocene sedimentary assemblage supports an interpretation that environments broadly similar to those in outer modern-day Shark Bay were wide spread across the Great Australian Bight during portions of marine isotope stages 2, 3 and 4. The high δ¹³C values of the Pleistocene M. vertebralis are interpreted to reflect enhanced photosynthetic activity that depletes dissolved carbonate in ¹²C in such shallow, saline settings. These hypersaline environments formed during periods of lower sea-level when shallow-waters (< 20 m depth) extended from the shoreline over ~ 100 km across what is currently a relatively deep shelf. This study indicates that shelf bathymetry was a critical determinant of past environments of deposition across the Great Australian Bight.     

Note on the analysis of light curves of eclipsing binaries with dissimilar components

The term l _per giving a correction needed to reduce the light curves of eclipsing binaries with dissimilar components to those of rectifiable models with similar components is discussed in view of a practical definition of the luminosities of the components. A new form of the term is proposed. Furthermore, a way is shown for applying this term also when the light curve has already been rectified in the usual manner.Mitteilung des Astronomischen Instituts der Universität Tübingen Nr. 108.     

Wide—Band Multi—spectral Space for Color Representation

This paper develops a wide-band multi-spectral space for color representation with Aitken PCA al-gorithm. This novel mathematical space using the broad-band spectra matching metod aims at improving the accuracy of color representation as well as reducing costs for processing and storing multi-spectral images.The results show that the space can present our experimental original spectral spaces(i,e.Munsell color matt and DIN-6164 color chips)with high efficiency,and that the spanning space with three eigenvectors can present the original space at more than 98% CSCR,and when 5eigenvectors are used it can cover almost the whole original spaces.     

Surface water quality and sediment geochemistry in the Gualaxo do Norte basin,eastern Quadrilátero Ferrífero,Minas Gerais,Brazil

This paper describes the geochemistry of water and sediment samples downstream from two iron mines in the Gualaxo do Norte River basin, north of Mariana city, Minas Gerais state, Brazil. Electric conductivity, total dissolved solids, pH, E_h, Na, K, Ca, Mg and trace elements (Fe, Mn, Al, Cd, Ni, Cr, Zn, As, Pb, Co, Sb, Cu, Mo, Rb, Sr, Ti, V, Y, Zr and Ba) have been analysed in water and sediments. The observed Na anomalies are mainly associated with the iron mine processing plants. Enriched concentrations of iron and manganese were only observed in rudimentary gold exploitation areas (prospectors) and where supergenic alteration of the banded iron formation has occurred. Iron and manganese background values are in some places higher than the limits established by Brazilian legislation. Mn, As, Sb and Ba anomalies have been observed in sediments. Their main source is associated with the sulphide-rich mineral deposits in the spring of the Gualaxo do Norte River and not directly related to the present iron exploitation in the region. Background values are proposed for the studied region.     

Shallow high-resolution seismics and reprocessing of industry profiles in southern Bavaria: The Molasse and the northern Alpine front

The purpose of this seismic investigation in the Upper Bavarian Miesbach area, as part of the international TRANSALP project, was to study the tectonic contact between the autochthonous Foreland Molasse and the allochthonous Folded Molasse marking the tectonic front of the Alpine orogen. Another specific target was the dip of the frontal emerging main thrust of the tectonic units Helveticum/Ultrahelveticum and Rhenodanubian Flysch overriding the Folded Molasse. Twelve seismic profiles obtained from the hydrocarbon industry were reprocessed. From the Foreland Molasse southward to the Autochthonous Molasse in the subsurface of the overthrust Folded Molasse conspicuous features such as steep normal faults at the Molasse base, S-directed thickening of Molasse sediments or sedimentary discordant base of Upper Marine Molasse can be recognized.Shallow high-resolution seismic measurements were conducted along two profiles across the tectonic contact between Foreland Molasse and Folded Molasse, as well as along a profile across the frontal emerging main thrust of the Helveticum/Ultrahelveticum and the Rhenodanubian Flysch. Geological structures could be identified in the top 300–500 ms two-way traveltime interval, which is hardly possible with the usual deep-seismic method. The method thus provides a bridge between deep-reflection seismics and surface geology.In contrast to the western Bavarian Molasse zone, the tectonic boundary between the Foreland Molasse and the Folded Molasse in the investigated area is not characterized by a large blind-thrust triangle zone but by a simple south-dipping thrust plane. Adjacent to the S follow several steeply south-dipping inverse Molasse thrust slices and the Miesbach syncline. The inverse thrust slices are interpreted as the overturned and sheared northern limb of a fault propagation fold, which linked the Folded Molasse to the Foreland Molasse during a final orogenic phase.The main thrust of the Helveticum/Ultrahelveticum and the Rhenodanubian Flysch are well imaged in the near-surface interval of the high-resolution reflection seismic data. In contrast to previously published results, these thrust planes show a gentle dip to the S from the surface down to at least 500–1000 m depth.     

The earthquake of Carnuntum in the fourth century a.d. – archaeological results, seismologic scenario and seismotectonic implications for the Vienna Basin fault, Austria

Excavations in the former Roman provincial capital of Pannonia Superior, Carnuntum, 40 km east of Vienna revealed damaged masonry structures from many parts of the ancient settlements. A compilation of structurally damaged buildings has formerly been given by Kandler (Acta Archaeol Acad Sci Hung, 41:313–336, 1989), who related damage to an earthquake in the middle of the fourth century a.d. This paper reviews and supplements these data, and discusses the significance of the style of damage. It is concluded that seismic damage is the only likely interpretation for the damaging mechanism. Although archaeological age dating for the individual collapsed buildings only constrains the timing of their destruction to a few decades around 350 a.d., we assume a single damaging event. In spite of the restrictions on damage assessment by the nature of the archaeological data, it is possible to give a reasonable appraisal of macroseismic intensity. The tentative seismological interpretation of damage leads to an intensity estimate of about nine of the European macroseismic scale (EMS-1998). Comparison with macroseismic data of modern earthquakes in the region, which show a rapid decrease of intensity with distance form the epicentre, indicate a near-by seismic source unless exceptionally high epicentral intensities are assumed for the fourth century event. The most likely source is an active sinistral strike-slip fault (Lassee Fault) passing about 8 km NW of the archaeological site. The fault belongs to Vienna Basin fault system with about 2 mm sinistral movement per year. The system is characterized by fault segmentation and distinct seismicity along the different segments. Moderate seismicity during the last centuries at the southern segments (e.g., Schwadorf 1927, I ₀=8) strongly contrasts from the Lassee fault segment with Carnuntum as the only known severe earthquake. The earthquake of Carnuntum provides evidence for the overall seismic style of deformation along this segment, which previously has not been regarded seismically active. Also, the fourth century earthquake is the strongest event known from the Vienna Basin fault so far.     

Methods to calculate sedimentation rates of floodplain soils in the middle region of the Elbe River

This study presents different methods to quantify the historic and recent sedimentation of floodplain soils along the Elbe River. These methods include the comparison of surface elevations, the quantification of sedimentation with the aid of anthropogenic and geogenic tracers, sediment trap studies, and the calculation of load balances. Selected results from sites at the lower section of the middle Elbe River are presented and verified. The results show that several methods are suitable. In future work it should be possible, depending on the available soil and sediment data, to calculate sedimentation in Elbe River floodplain and the loss of retention volume for larger areas.     

A Method for Modeling of a Creeping Slope with a Visco-Hypoplastic Material Law

This paper presents the numerical simulation of a creeping slope in Upper Austria, using a visco-hypoplastic material law which describes the mechanical behavior of cohesive soils allowing for viscous effects, i.e. creep and relaxation. The method consists of: (1) determination of the parameters of the material law, based on laboratory tests on soil samples taken from the slope; (2) simulation of the laboratory tests with an element test program in which the used material law was implemented, in order to test whether the model holds for the soils studied; and (3) simulation of slope movements at different sections along the slope, assuming an infinite slope. The simulation results fit well with the field measurements. This demonstrates that despite strongly simplified boundary conditions and limited availability of subsurface data (e.g. density) the visco-hypoplastic law is a promising tool for predicting creep movements.