Mineralogical,geochemical and microfabric evidences of gypsum crusts: a case study from Budapest

High levels of SO₂ and particulate pollution enable the rapid development of gypsum-rich weathering crusts in Budapest. Two types of white crusts, thin and thick ones, and two forms of black crusts, laminar and framboidal ones, were studied in limestone buildings of the parliament and Citadella. The percentage of crust cover and damage categories were documented on selected walls. Petrographic, XRD, XRF and sulphur isotope analyses were performed under laboratory conditions to understand the mechanism of crust formation. White crusts found both on exposed and sheltered walls display a calcite-rich layer with gypsum, while black crusts are enriched with gypsum. The sulphur isotopic composition of white and black crusts overlaps, but the crusts are slightly enriched in heavy isotopes compared to rainwater. S content, Si/Al ratios and particulates in black crusts suggest that air pollution (SO₂, dust) contributes to black crust formation. The accumulation of sulphur and Zn enrichment of white crusts were also documented indicating that under high pollution levels, even these compound can accumulate on exposed facades.     

Outer convection zones and internal temperatures of cool white dwarfs

The outer convection zone of the low-temperature white dwarf Van Maanen 2 has been studied for two different atmospheric models given byWeidemann (1960). A slight modification of the standard mixing length theory and the abundances derived by Weidemann have been used.The thickness of the convection zone is about 8 km for the atmospheric model withT _eff=5780 K,g=10⁸ cm sec^–2 and about 23 km forT _eff=5040,g=3.16×10⁷K. In both cases the temperature at the lower boundary of the convection zone is about 9.8×10⁵K. It is shown that this temperature corresponds approximately to the transition temperatureT _tr to the (almost) isothermal core of the white dwarf. This value is considerably lower than the values ofT _tr discussed in the literature until now.The outer convection zone consists of an upper completely non-degenerate part and a lower part with moderate degeneracy. In this lower part the degree of degeneracy is practically independent of depth.     

Elimination of Carbamazepine,Diclofenac and Naproxen from Treated Wastewater by Nanofiltration

Most conventional wastewater treatment plants remove very small amounts of micropollutants, such as pharmaceuticals. Here, the ability of two different types of submerged nanofiltration flat sheet modules to remove pharmaceuticals from wastewater is analyzed. The two nanofiltration membranes were used at relatively low pressures of only 0.3 and 0.7 bar. At such low pressures, the membranes did not retain salts to a great extent. This is advantageous in wastewater treatment because no salt concentrate is produced. Carbamazepine was retained only slightly by the nanofiltration membranes, whereas approximately 60% of diclofenac and naproxen were retained by both membranes. This level of effectiveness might not be enough to justify the use of such a system as an additional treatment step in wastewater treatment plants.     

Oxidation of the Kaapvaal lithospheric mantle driven by metasomatism

The oxidation state, reflected in the oxygen fugacity (fO₂), of the subcratonic lithospheric mantle is laterally and vertically heterogeneous. In the garnet stability field, the Kaapvaal lithospheric mantle becomes progressively more reducing with increasing depth from Δlog fO₂ FMQ-2 at 110 km to FMQ-4 at 210 km. Oxidation accompanying metasomatism has obscured this crystal-chemical controlled depth-fO₂ trend in the mantle beneath Kimberley, South Africa. Chondrite normalized REE patterns for garnets, preserve evidence of a range in metasomatic enrichment from mild metasomatism in harzburgites to extensive metasomatism by LREE-enriched fluids and melts with fairly unfractionated LREE/HREE ratios in phlogopite-bearing lherzolites. The metasomatized xenoliths record redox conditions extending up to Δlog fO₂ = FMQ, sufficiently oxidized that magnesite would be the stable host of carbon in the most metasomatized samples. The most oxidized lherzolites, those in or near the carbonate stability field, have the greatest modal abundance of phlogopite and clinopyroxene. Clinopyroxene is modally less abundant or absent in the most reduced peridotite samples. The infiltration of metasomatic fluids/melts into diamondiferous lithospheric mantle beneath the Kaapvaal craton converted reduced, anhydrous harzburgite into variably oxidized phlogopite-bearing lherzolite. Locally, portions of the lithospheric mantle were metasomatized and oxidized to an extent that conversion of diamond into carbonate should have occurred. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

The Decline and Restoration of a Coastal Lagoon (Lake Veere) in the Dutch Delta

The former tidal inlet Lake Veere was turned into a stagnant brackish lake in 1961. Ever since, the system has shown a continuous degradation. The current study shows the monitoring results for the macrozoobenthic communities and the abiotic conditions for the period 1990–2008. This includes the first step to remediation, the restoration of the exchange between the tidal marine Eastern Scheldt and Lake Veere in 2004. A continuous decline in water clearance co-occurring with decreasing macrofauna densities and richness was observed till 2004. Water quality (e.g., secchi depth, nutrient levels, and oxygen conditions) improved significantly after the measure at a higher salinity level with less variation. But the macrofauna densities, biomass, and diversity did not improve yet. First indications of changes in the benthic communities by arrival of new and returning species are however observed and show that restoration at macrofauna level follows the improved abiotic conditions with a delay of several years.     

Petrographische und Kalium-Argon-Untersuchungen an basischen tertiären Vulkaniten zwischen Westerwald und Vogelsberg

Between the upper tertiary volcanic areas of Westerwald and Vogelsberg (central Western Germany) occur more than 40 isolated tertiary volcanic dikes, eroded necks, plugs and domes. Twelve of these volcanic rocks have been investigated petrographically and chemically and classified by means of their modal and chemical composition. Additional modal analyses have been performed on seven other volcanics. On seventeen volcanic occurences K-Ar-whole rock age determinations have been made. The K-Ar age determinations yield- with the exception of an olivine-nephelinite — values between 27 and 15 Ma. Regarding the known intervals of volcanic activities of the Westerwald- and Voge1sberg-areas, most of the examined volcanics can be related genetically with one of the adjacent volcanic areas. There seems to be no geographical overlapping of volcanics showing Westerwaldages and Vogelsberg-ages. A possible influence of excess-Ar-bearing phases (e. g. mantle xenoliths) and an Ar-loss of constituent matter of the groundmass have been estimated by additional age determinations of enriched samples. These influences — partially compensating each other — may shift the K-Ar whole rock age to a maximum of 5 % and thus do not exceed the dimension of the standard deviations. A distinct NNE-SSW-striking fault in the region between Marburg and Gießen is situated parallel with the eastern border of the “Rheinisches Schiefergebirge”. Volcanics showing Westerwald-age and Vogelsberg-age respectively reach this fault, but obviously do not overlap it. Relations between rock-type an rock age, as it has been observed for the volcanics of the northern Hessian Depression (Kreuzer et al. 1973;Wedepohl 1982) cannot be proved certainly. On the other hand, similar to the basaltic rocks of the northern Hessian Depression, the youngest volcanic product is an olivine-nephelinite (9 Ma).     

The lower marine to lower freshwater Molasse transition in the northern Alpine foreland basin (Oligocene; central Switzerland–south Germany): age and geodynamic implications

The Wilhelmine Alpe section near Immenstadt (Allgäu, south Germany), which represents one of the best continuously exposed outcrops within the northern Alpine foreland basin, has been analyzed for magnetostratigraphic and palynostratigraphic signals. The section comprises the marine-to-terrestrial transition from Lower Marine (UMM) to Lower Freshwater Molasse (USM) sediments. Based on the correlation of the local magnetic pattern with the geomagnetic polarity timescale (GPTS) and palynostratigraphic data, an age of about 31 Ma is suggested for the UMM–USM transition in the Wilhelmine Alpe section. A comparison with coeval magnetostratigraphic sections from central and eastern Switzerland indicates that the regression of the UMM sea along the southern margin of the Molasse basin occurred strongly heterochronously between 31.5 and 30 Ma. The heterochroneity is attributed to the deposition of fan-delta and alluvial fan sediments which document that the overall marine conditions during the UMM were accompanied by strong clastic input derived from the rising Alps. This clastic contribution had a much stronger influence on the depositional pattern than previously thought.     

Remotely sensed assessment of water quality levels in the Pearl River Estuary, China

In this paper, a method of assessing water quality from satellite data is introduced. The composite pollution index (CPI) was calculated from measured chemical oxygen demand (COD) and nutrient concentration. The relationships between CPI and 240 band combinations of SeaWiFS water-leaving radiance were analyzed and the optimal band combination for estimating CPI was chosen from the 240 band combinations. An algorithm for retrieval of CPI was developed using the optimal band combination, (L₄₄₃ × L₅₁₀)/(L₄₁₂ + L₄₉₀). The CPI was estimated from atmospherically corrected SeaWiFS data by employing the algorithm. Furthermore, the CPI value range for each water quality level was determined based on data obtained from 850 samples taken in the Pearl River Estuary. The remotely sensed CPIs were then transferred to water quality levels and appropriate maps were derived. The remotely sensed water quality level maps displayed a similar distribution of levels based on in situ investigation issued by the State Ocean Administration, China. This study demonstrates that remote sensing can play an important role in water quality assessment.     

Thermal conductivity measurements of road construction materials in frozen and unfrozen state

A series of thermal conductivity measurements for various materials was performed in a large climate chamber. The size of the chamber allowed the preparation of relatively large samples in a controlled thermal environment. Three types of thermal sensors were used: (1) two needle probes; (2) a grid of temperature sensors, evenly distributed inside the sample; (3) two additional thermal probes, which were simplified versions of an instrument originally developed for measuring thermal properties of the ice/dust mixture expected to exist at the surface of a comet nucleus. They consist of a series of individual temperature sensors integrated into a glass fibre rod. Each of these sensors can be operated in an active (heated) or passive (only temperature sensing) mode. The following sample materials were used: fine-grained reddish sand, coarse-grained moist sand, gravels with various grain size distributions from < 1 cm up to about 6 cm, and for comparison and calibration pure water (with convection suppressed by adding agar-agar), compact ice, and compact granite. Of particular interest are the measurements with composite samples, like stones embedded in an agar-agar matrix. We describe the evaluation methods and present the results of the thermal conductivity measurements.