Application of the Unified Stream Assessment Method to Determine the Direction of Revitalization of Heavily Transformed Urban Rivers

Water Resources - The issues related to the assessment of the hydro morphological status of urban rivers in order to identify the revitalisation actions possible to be carried out, has been...     

A Late Paleoproterozoic (1.80 Ga) subduction-related mafic igneous suite from Lomza, NE Poland

The Lomza orthoamphibolites in the crystalline basement of NE Poland, dated at 1802 ± 9 Ma by SHRIMP zircon U–Pb, are characterized by high incompatible and REE element contents. These features, the low Nb, and the position of the rock compositions on La–Y–Nb, Zr–Nb/Zr and Zr–Nb–Y tectonomagmatic discrimination diagrams, suggest that the metavolcanics formed in a subduction setting, possibly within a continental margin island arc. The likely extension of the belt of Paleoproterozoic mafic magmatism from Latvia and Lithuania into NE Poland provides convincing evidence for the existence of an active plate margin in that region at that time.     

Correlating specific conductivity with total hardness in gypsum karst waters

Modern digital conductivity meters are readily portable, robust, cheap, and give precisely reproducible values of specific electrical conductivity (SpC, in µS cm^?1). Here we investigate the accuracy of their estimates of the amounts of gypsum dissolved in waters collected in gypsum karst terrains, expressed as total hardness (TH) in mg L^?1 of CaSO₄·2H₂O (GYP). Total dissolved solid concentrations (TDS) are also considered. Curves obtained with the program PHREEQC, for the dissolution of pure gypsum in water at 25 C, are compared with 574 comprehensive water chemical analyses selected from gypsum karst studies in Europe and the Americas. Principal common and foreign ions encountered are the BNC group (bicarbonates, nitrates, chlorides). It is found that GYP = 1·12^·SpC + 62 where BNC < 33% (Cl^? < 5%), with one standard error <5% for waters with SpC > 2400 µS cm^?1; GYP = 0·74^·SpC + 777 where BNC < 33% (5% ≤ Cl^? < 15%), with one standard error <10% for waters with SpC > 3100 µS cm^?1; GYP = 0·97^·SpC ? 209 where BNC < 33% and Cl^? ≥ 15%, with one standard error <10% for samples with SpC > 4300 µS cm^?1. There are similar results for the more complex waters found in gypsum karsts where much carbonate rock or salt is also present, to the limit of BNC < 50% for what may reasonably be defined as ‘gypsum waters’. Values of R² for linear correlations of different subsets of the water samples range from 0·69 to 0·96, the majority being >0·8. Copyright © 2006 John Wiley & Sons, Ltd.     

Biostratigraphy of the lower red shale interval in the Rhenodanubian Flysch Zone of Austria

In the Rhenodanubian Flysch Zone of Austria, between the Aptian–Albian “Gault Flysch” and the Cenomanian–Turonian Reiselsberg Formation, an interval with predominant red shales (“Untere Bunte Schiefer”) occurs. In the Oberaschau section near Attersee (Upper Austria) a ca. 18-m-thick interval of alternating red and grey shales and marlstones with minor sandstones is present. Thin sandstone intercalations are interpreted as distal turbidites. Dinoflagellate cyst assemblages indicate the Litosphaeridium siphoniphorum Zone. The concurrent presence of Litosphaeridium siphoniphorum and Ovoidinium verrucosum in all samples allows a correlation to the lower part of this zone, thus defining a Late Albian–Early Cenomanian age. Based on foraminifera, the red beds can be assigned to the topmost Rotalipora appenninica Zone and the Rotalipora globotruncanoides Zone due to the presence of small morphotypes of the index taxa. Nannofossils indicate standard zones CC9/UC0 throughout the red interval, defined by the first occurrence of Eiffellithus turriseiffelii, and UC1 above the red shales. Based on these multistratigraphic data, a latest Albian–Early Cenomanian age can be inferred.     

Universal profile of dark matter haloes and the spherical infall model

I propose a modification of the spherical infall model for the evolution of density fluctuations with initially Gaussian probability distribution and scale-free power spectra in the Einsteinde Sitter universe as developed by Hoffman & Shaham. I introduce a generalized form of the initial density distribution around an overdense region and cut it off at half the interpeak separation, accounting in this way for the presence of the neighbouring fluctuations. Contrary to the original predictions of Hoffman & Shaham, the resulting density profiles within virial radii no longer have a power-law shape, but their steepness increases with distance. The profiles of haloes of galactic mass are well fitted by the universal profile formula of changing slope obtained as a result of N -body simulations by Navarro, Frenk & White. The trend of steeper profiles for smaller masses and higher spectral indices is also reproduced. The agreement between the model and simulations is better for smaller masses and lower spectral indices, which suggests that galaxies form mainly by accretion, while formation of clusters involves merging.     

CyberShake: A Physics-Based Seismic Hazard Model for Southern California

CyberShake, as part of the Southern California Earthquake Center??s (SCEC) Community Modeling Environment, is developing a methodology that explicitly incorporates deterministic source and wave propagation effects within seismic hazard calculations through the use of physics-based 3D ground motion simulations. To calculate a waveform-based seismic hazard estimate for a site of interest, we begin with Uniform California Earthquake Rupture Forecast, Version 2.0 (UCERF2.0) and identify all ruptures within 200?km of the site of interest. We convert the UCERF2.0 rupture definition into multiple rupture variations with differing hypocenter locations and slip distributions, resulting in about 415,000 rupture variations per site. Strain Green Tensors are calculated for the site of interest using the SCEC Community Velocity Model, Version 4 (CVM4), and then, using reciprocity, we calculate synthetic seismograms for each rupture variation. Peak intensity measures are then extracted from these synthetics and combined with the original rupture probabilities to produce probabilistic seismic hazard curves for the site. Being explicitly site-based, CyberShake directly samples the ground motion variability at that site over many earthquake cycles (i.e., rupture scenarios) and alleviates the need for the ergodic assumption that is implicitly included in traditional empirically based calculations. Thus far, we have simulated ruptures at over 200 sites in the Los Angeles region for ground shaking periods of 2?s and longer, providing the basis for the first generation CyberShake hazard maps. Our results indicate that the combination of rupture directivity and basin response effects can lead to an increase in the hazard level for some sites, relative to that given by a conventional Ground Motion Prediction Equation (GMPE). Additionally, and perhaps more importantly, we find that the physics-based hazard results are much more sensitive to the assumed magnitude-area relations and magnitude uncertainty estimates used in the definition of the ruptures than is found in the traditional GMPE approach. This reinforces the need for continued development of a better understanding of earthquake source characterization and the constitutive relations that govern the earthquake rupture process.     

Multiphase magmatic activity in the Variscan Kłodzko–Złoty Stok intrusion,Polish Sudetes: evidence from SHRIMP U–Pb zircon ages

International Journal of Earth Sciences - The Kłodzko–Złoty Stok intrusion (KZSI), located in the NE part of the Bohemian Massif of Central Europe, has preserved records of the...     

Protomylonite evolution potentially revealed by the 3D depiction and fractal analysis of chemical data from a feldspar

Tourmalinization associated with peraluminous granitic intrusions in metapelitic host-rocks has been widely recorded in the Iberian Peninsula, given the importance of tourmaline as a tracer of granite magma evolution and potential indicator of Sn-W mineralizations. In the Penamacor-Monsanto granite pluton (Central Eastern Portugal, Central Iberian Zone), tourmaline occurs: (1) as accessory phase in two-mica granitic rocks, muscovite-granites and aplites, (2) in quartz (±mica)-tourmaline rocks (tourmalinites) in several exocontact locations, and (3) as a rare detrital phase in contact zone hornfels and metapelitic host-rocks. Electron microprobe and stable isotope (δ¹⁸O, δD, δ¹¹B) data provide clear distinctions between tourmaline populations from these different settings: (a) schorl–oxyschorl tourmalines from granitic rocks have variable foititic component (^X□ = 17–57 %) and Mg/(Mg + Fe) ratios (0.19–0.50 in two-mica granitic rocks, and 0.05–0.19 in the more differentiated muscovite-granite and aplites); granitic tourmalines have constant δ¹⁸O values (12.1 ± 0.1 ‰), with wider-ranging δD (?78.2 ± 4.7 ‰) and δ¹¹B (?10.7 to ?9.0 ‰) values; (b) vein/breccia oxyschorl [Mg/(Mg + Fe) = 0.31–0.44] results from late, B- and Fe-enriched magma-derived fluids and is characterized by δ¹⁸O = 12.4 ‰, δD = ?29.5 ‰, and δ¹¹B = ?9.3 ‰, while replacement tourmalines have more dravitic compositions [Mg/(Mg + Fe) = 0.26–0.64], close to that of detrital tourmaline in the surrounding metapelitic rocks, and yield relatively constant δ¹⁸O values (13.1–13.3 ‰), though wider-ranging δD (?58.5 to ?36.5 ‰) and δ¹¹B (?10.2 to ?8.8 ‰) values; and (c) detrital tourmaline in contact rocks and regional host metasediments is mainly dravite [Mg/(Mg + Fe) = 0.35–0.78] and oxydravite [Mg/(Mg + Fe) = 0.51–0.58], respectively. Boron contents of the granitic rocks are low (<650 ppm) compared to the minimum B contents normally required for tourmaline saturation in granitic melts, implying loss of B and other volatiles to the surrounding host-rocks during the late-magmatic stages. This process was responsible for tourmalinization at the exocontact of the Penamacor-Monsanto pluton, either as direct tourmaline precipitation in cavities and fractures crossing the pluton margin (vein/breccia tourmalinites), or as replacement of mafic minerals (chlorite or biotite) in the host-rocks (replacement tourmalinites) along the exocontact of the granite. Thermometry based on ¹⁸O equilibrium fractionation between tourmaline and fluid indicates that a late, B-enriched magmatic aqueous fluid (av. δ¹⁸O ~12.1 ‰, at ~600 °C) precipitated the vein/breccia tourmaline (δ¹⁸O ~12.4 ‰) at ~500–550 °C, and later interacted with the cooler surrounding host-rocks to produce tourmaline at lower temperatures (400–450 °C), and an average δ¹⁸O ~13.2 ‰, closer to the values for the host-rock. Although B-metasomatism associated with some granitic plutons in the Iberian Peninsula seems to be relatively confined in space, extending integrated studies such as this to a larger number of granitic plutons may afford us a better understanding of Variscan magmatism and related mineralizations.     

Synoptic conditions of heavy snowfalls in Europe

Synoptic conditions of heavy snowfalls at four stations in Europe (Oslo, Bremen, Smolensk and Budapest) were analyzed using daily data of snow cover depth from 50 winter seasons (1960/1961–2009/2010). Composite maps of the sea level pressure and 500 hPa geopotential height means and anomalies were presented for the days with an increase in snow depth by ≥10 cm, for each station separately. In the same way, maps were presented for the 850 hPa temperature and the precipitable water content. Additionally, 48 h back trajectories of air masses for the chosen days with the highest amount of snowfall were constructed, using the NOAA HYSPLIT model. Negative anomalies of sea level pressure and 500 hPa heights, which correspond to low‐pressure systems spreading over Europe, are prerequisites for the occurrence of heavy snowfalls at each analyzed location. In Budapest, heavy snowfalls appear as a result of cyclonic cold fronts from the Mediterranean Sea. Another typical location of snow‐bringing low‐pressure systems is the Baltic Sea region. Negative pressure anomalies over the North Atlantic with a low‐pressure centre over the Norwegian Sea cause snowfalls in Oslo. There are two main sources of air masses bringing abundant snowfalls in Europe: the Atlantic region and Mediterranean. According to back trajectories, the humid air masses are transported over long distances and on the way they are shifted from the low troposphere in the source regions to the upper layers.