Shock‐metamorphic microfeatures in chert from the Jebel Waqf as Suwwan impact structure,Jordan

Abstract– The petrographic investigation of a shocked, chalcedony‐, quartzine‐, and quartz‐bearing allochthonous chert nodule (probably Upper Cretaceous) recovered from surficial wadi gravels in the inner parts of the central uplift of the approximately 6 km in diameter Jebel Waqf as Suwwan impact structure, Jordan, reveals new potential shock indicators in microfibrous–spherulitic silica, in addition to well‐established shock‐metamorphic effects in coarser crystalline quartz. The microcrystalline chert groundmass exhibits a macroscopic dendritic and suborthogonal fracture pattern commonly associated with thin “recrystallization bands” that intersect the pre‐existing diagenetic chert fabric. Fibrous aggregates of quartzine spherulites in chalcedony‐quartzine‐quartz veinlets locally have a shattered appearance and show conspicuous “curved fractures” perpendicular to the quartzine fiber direction (and parallel to [0001]) that commonly trend subparallel to planar fractures (PFs) in neighboring shocked quartz. Quartz exhibits PFs, feather features (FFs), and mainly single sets of planar deformation features (PDFs) parallel to the basal plane (0001) (Brazil twins) and, rarely, additional PDFs parallel to {101¯3}. Shock petrography indicates shock pressures of ≥10 GPa and high shock‐induced differential stresses that affected the chert nodule. The internal crosscutting relationships of primary diagenetic and impact‐related deformational features together with shockpressure estimates suggest that the curved fractures across quartzine spherulites might represent specific (low‐ to medium‐pressure) shock‐metamorphic features, possibly in structural analogy to basal plane PFs in quartz. The dendritic–suborthogonal fractures in the microcrystalline chert groundmass and recrystallization bands are likely related to impact‐induced shear deformation and recrystallization, respectively, and cannot be considered as definite shock indicators.     

Extended Sediment Quality Rating for Trace Elements in Urban Waters – Case Study Klinke,Germany

The European Water Framework Directive (WFD) commits European Union member states to achieving good ecological status in all water bodies by 2015. For sediments the definition of good chemical status is based on numerical sediment quality guidelines. The aqua regia fraction is thus used for the evaluation of heavy metal concentrations in sediments. The chemical constituents in sediments responsible for mobility and toxicity are not considered generally. This article presents the combining of the sequential BCR procedure, for determining the chemical species of relevant elements, with the geoaccumulation index principle a numerical classification method for sediment quality guidelines. Using the BCR method it can be demonstrated that changes in element speciation can lead to more highly mobile species of trace elements which may affect the hazardous potential of sediments despite the “good chemical status” classification for aqua regia digestions. The Klinke stream is an urban surface water body located in Magdeburg, the state capital of Saxony‐Anhalt, Germany. Using this stream as an example it is shown that this additional information helps to describe the dynamics and discharge of the trace elements Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Sr, Mo, Pd, Cd, Sb, Ba, Pb, Bi, and U into the Elbe River from urban water bodies.     

The distribution of capital forms between cities and suburbs and their impact on social justice in space

Questions of justice have been raised in recent years when contending with the social costs of urban sprawl. But this field of inquiry suffers from the difficulty of translating the abstract notion of justice into measurable spatial indices. The aim of this paper is to empirically measure the liberal notion of justice in the metropolitan region of Tel Aviv by adopting Pierre Bourdieu’s theory of three forms of capital. Under this theory, the formation of economic, cultural, and social capital in the individual’s living environment determines the person’s exposure to different sets of life-chances (i.e., capabilities), thus influencing equality of opportunity (i.e., social justice) in space. The analysis reveals that suburban inhabitants benefit from a larger accumulation of the three forms of capital than do urban inhabitants. Accumulation of these capitals has a positive effect on exposure to life-chances, thus enhancing spatial segregation between cities and suburbs.     

Sediment dynamics in the Black Sea: numerical modelling and remote sensing observations

Here, we address the sediment dynamics in the Black Sea based on analysis of remote sensing data from the Medium Resolution Imaging Spectrometer and numerical simulations with Nucleus for European Modelling of the Ocean model. Boundary conditions consist of realistic meteorological forcing, including significant wave height generated by wave prediction model. A number of sensitivity runs was analysed with the aim to find the most suitable parameters governing sediment fluxes. The comparison between numerical simulations and remote sensing data gives credibility to the quality of simulations. The combined effect of wind waves and currents in the bed layer controls the sediment resuspension that appears to be the major basin-wide source of sediment. Sensitivity experiments included or excluded different forcing terms, e.g. sediment flux from rivers enable to determine the spatial extensions of different point sources. It is concluded that wind-wave forcing is manifested in the sediment dynamics through episodic high energy events contributing to the increase of horizontal sediment fluxes over the northwestern shelf. Both satellite images and numerical model simulations demonstrated that the penetration of suspended sediment into the basin interior was governed by the dynamics of coastal and open-ocean eddies. While fine sediment at sea surface could cross the continental slope propagating into the open ocean, coarser fractions follow the bottom and their penetration into the open ocean is limited. The conclusion is thus that the deposition patterns correlate with the specific shape of Black Sea topography, and the largest depositions are observed in the area of continental slope.     

Identification of the environmentally safe fairway in the South-Western Baltic Sea and Kattegat

Application of the preventive techniques for the optimisation of fairways in the south-western Baltic Sea and the Kattegat in terms of protection of the coastal regions against current-driven surface transport of adverse impacts released from vessels is considered. The techniques rely on the quantification of the offshore domains (the points of release of adverse impacts) in terms of their ability to serve as a source of remote, current-driven danger to the nearshore. An approximate solution to this inverse problem of current-driven transport is obtained using statistical analysis of a large pool of Lagrangian trajectories of water particles calculated based on velocity fields from the Denmark’s Meteorological Institute (DMI)/BSH cmod circulation model forced by the DMI-HIRHAM wind fields for 1990–1994. The optimum fairways are identified from the spatial distributions of the probability of hitting the coast and for the time (particle age) it takes for the pollution to reach the coast. In general, the northern side of the Darss Sill area and the western domains of the Kattegat are safer to travel. The largest variations in the patterns of safe areas and the properties of pollution beaching occur owing to the interplay of water inflow and outflow. The gain from the use of the optimum fairways is in the range of 10–30?% in terms of the decrease in the probability of coastal hit within 10?days after pollution release or an increase by about 1–2?days of the time it takes for the hit to occur.     

Observing Gravity Change in the Fennoscandian Uplift Area with the Hanover Absolute Gravimeter

The Nordic countries Norway, Sweden, Finland and Denmark are a key study region for research of glacial isostasy. In addition, such research offers a unique opportunity for absolute gravimetry to show its capability as a geodetic tool for geophysical research. Within a multi-national cooperation, annual absolute gravity measurements have been performed in Fennoscandia by IfE since 2003. For the Hanover gravimeter FG5-220, overall accuracy of ±30?nm/s² is indicated for a single station determination. First results of linear gravity changes are derived for ten stations in the central and southern part of the uplift area. Comparing with the rates predicted by glacial rebound modelling, the gravity trends of the absolute measurements differ by 3.8?nm/s² per year (root-mean-square discrepancy) from the uplift model. The mean difference between observed and predicted rates is 0.8?nm/s² per year only. A proportionality factor of ?1.63?±?0.20?nm/s² per mm has been obtained, which describes the mean ratio between the observational gravity and height rates.