From Cadomian arc to Ordovician passive margin: geochemical records preserved in metasedimentary successions of the Orlica-Śnieżnik Dome in SW Poland     

Jacek Szczepański  Sławomir Ilnicki 《International Journal of Earth Sciences》2014,103(3):627-647

The chemical composition of metamorphosed siliciclastic rocks in the Orlica-?nie?nik Dome (Bohemian Massif) identifies the main sources for the Neoproterozoic [the M?ynowiec Formation (MF)], Early Cambrian [the Stronie Formation (SF)] and Late Cambrian/Early Ordovician [the Goszów quartzites (GQ)] sediments. The MF developed from erosion of a Cadomian magmatic arc along the northern Gondwana margin. The variegated SF, with supra-subduction affinities, shows chemical characteristics pointing to erosion of the freshly exhumed Cadomian orogen and detritus deposition in the back-arc basin. The very different chemical features of the GQ indicate deposition in a basin sited on a passive continental margin. The explanation proposed for the observed changes in chemical composition involves three main stages: (1) The pre ~540 Ma evolution of an active continental margin and related back-arc basin ceased with the collision and accretion of the magmatic arc to the Gondwana margin; (2) Early Cambrian rift to drift transition (540–500 Ma) and development of a depositional basin filled with detritus derived from remnants of the magmatic arc; (3) Peri-Gondwana break-up leading to the formation of shallow-water passive margin depositional basins filled with quartz-rich detritus resembling Early Ordovician Armorican quartzites known from other parts of the Variscan Belt.  相似文献   

Analysis of labile form of aluminum and heavy metals in bottom sediments from Kongsfjord, Isfjord, Hornsund fjords     

Marcin Frankowski  Anetta Zioła-Frankowska 《Environmental Earth Sciences》2014,71(3):1147-1158

The paper presents study results obtained for the bottom sediment samples of fjords Kongsfjord, Isfjord, Hornsund in the form of surface samples and their core profiles. The concentrations of labile form of aluminum and heavy metals were determined using the single-stage extraction with 3 mol L^?1 HCl. The obtained results allowed defining the occurrence of variability of labile aluminum form in the samples of bottom sediments of the studied fjords depending on the point and depth of sample collection. The conducted chemometric analysis allowed for the study of spatial variability of aluminum occurrence in the area of the investigated fjords. Based on the analysis, the correlations between aluminum and heavy metals were determined.  相似文献   

Multi-scale aquifer characterization and groundwater flow model parameterization using direct push technologies     

Bart Rogiers  Thomas Vienken  Matej Gedeon  Okke Batelaan  Dirk Mallants  Marijke Huysmans  Alain Dassargues 《Environmental Earth Sciences》2014,72(5):1303-1324

Direct push (DP) technologies are typically used for cost-effective geotechnical characterization of unconsolidated soils and sediments. In more recent developments, DP technologies have been used for efficient hydraulic conductivity (K) characterization along vertical profiles with sampling resolutions of up to a few centimetres. Until date, however, only a limited number of studies document high-resolution in situ DP data for three-dimensional conceptual hydrogeological model development and groundwater flow model parameterization. This study demonstrates how DP technologies improve building of a conceptual hydrogeological model. We further evaluate the degree to which the DP-derived hydrogeological parameter K, measured across different spatial scales, improves performance of a regional groundwater flow model. The study area covers an area of ~60 km² with two overlying, mainly unconsolidated sand aquifers separated by a 5–7 m thick highly heterogeneous clay layer (in north-eastern Belgium). The hydrostratigraphy was obtained from an analysis of cored boreholes and about 265 cone penetration tests (CPTs). The hydrogeological parameter K was derived from a combined analysis of core and CPT data and also from hydraulic direct push tests. A total of 50 three-dimensional realizations of K were generated using a non-stationary multivariate geostatistical approach. To preserve the measured K values in the stochastic realizations, the groundwater model K realizations were conditioned on the borehole and direct push data. Optimization was performed to select the best performing model parameterization out of the 50 realizations. This model outperformed a previously developed reference model with homogeneous K fields for all hydrogeological layers. Comparison of particle tracking simulations, based either on the optimal heterogeneous or reference homogeneous groundwater model flow fields, demonstrate the impact DP-derived subsurface heterogeneity in K can have on groundwater flow and solute transport. We demonstrated that DP technologies, especially when calibrated with site-specific data, provide high-resolution 3D subsurface data for building more reliable conceptual models and increasing groundwater flow model performance.  相似文献   

Luminescence and other spectroscopic properties of purple and green Cr-clinochlore     

Maria Czaja  Mariola Kądziołka-Gaweł  Radosław Lisiecki  Sabina Bodył-Gajowska  Zbigniew Mazurak 《Physics and Chemistry of Minerals》2014,41(2):115-126

For the first time ever, the luminescence spectra of Cr³⁺ centers in two chlorite crystals are presented. Chromium ions occupy the strong crystal-field site M4 in the brucite sheet and the intermediate crystal-field site in the inner octahedral sheet for purple and green chlorite, respectively. We discuss the influence of an effective positive charge on the Cr³⁺ ion and an effective negative charge of ligands on the differences in the values of the Dq and B parameters. It is concluded that the presence of Fe²⁺ ions and other point defects, as well as concentration quenching, causes the very short luminescence lifetimes of chromium ions.  相似文献   

Numerical modeling and neural networks to identify model parameters from piezocone tests: I. FEM analysis of penetration in two‐phase continuum     

Rafał F. Obrzud  Andrzej Truty  Laurent Vulliet 《国际地质力学数值与分析法杂志》2011,35(16):1703-1730

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Transverse Oscillations in Coronal Loops Observed with TRACE – II. Measurements of Geometric and Physical Parameters     

Aschwanden  Markus J.  De Pontieu  Bart  Schrijver  Carolus J.  Title  Alan M. 《Solar physics》2002,206(1):99-132

Solar Physics - We measure geometric and physical parameters oftransverse oscillations in 26 coronal loops, out of the 17 events described in Paper I by Schrijver, Aschwanden, and Title (2002)....  相似文献   

Periglacial and Fluvial Factors Controlling the Sedimentation of Pleistocene Breccia in NW Poland          下载免费PDF全文

Piotr Weckwerth  Małgorzata Pisarska‐Jamroży 《Geografiska Annaler: Series A, Physical Geography》2015,97(2):415-430

Breccias were investigated on the terrace of the Toruń‐Eberswalde ice‐marginal valley at Rozwarzyn (NW Poland). Breccia layers include soft‐sediment clasts with diameters between 2 and 256 mm and soft‐sediment megaclasts with diameters from 256 mm to 7 m. The shape of the soft‐sediment clasts and megaclasts (derived from frozen sediments) in the breccia is diverse: from angular and irregular in the case of debris‐flow breccias to slightly rounded and tabular in fluvial breccias. These two types of breccias were developed during the Late Weichselian when the periglacial climate favored extensive lateral erosion by currents of frozen braided channels in the ice‐marginal valley. The dual presence of breccias of fluvial and debris‐flow origin in channel deposits is unique for Quaternary sediments. Zones of breccias existed in the channels where scours and obstacle marks related to megaclasts developed. The study of breccias shed new light on the fluvial processes in ice‐marginal valleys during the Pleistocene and can be considered as diagnostic for fluvio‐periglacial conditions.  相似文献   

Relationship between the environmental and hydrogeological elements characterizing groundwater-dependent ecosystems in central Poland     

Ewa Krogulec  Sebastian Zabłocki 《Hydrogeology Journal》2015,23(7):1587-1602

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Integral Turbulence Statistics Over a Central European City Centre   总被引：2，自引：2，他引：0  

Krzysztof Fortuniak  Włodzimierz Pawlak  Mariusz Siedlecki 《Boundary-Layer Meteorology》2013,146(2):257-276

Atmospheric measurements over 5 years (2005–2010) at two sites in ?ód?, central Poland have been analyzed to develop a better understanding of turbulence in urban areas. Fast response wind velocity, temperature, humidity and CO₂ concentration were measured using sonic anemometers and gas analyzers, placed on narrow masts at 37 and 42 m above the ground. The measurements were used to calculate standard deviations of each parameter, and were then normalized according to local Monin–Obukhov similarity theory and plotted as a function of stability parameter ζ = z′/L. Results for the wind components show typical scaling with a power law with exponent ±1/3 in the free convection limit, and that approaches a constant value close to neutral stratification. For stable conditions, the constant value in the neutral limit remains the same for stability parameters lower than 0.1–0.2, then increases. The normalized standard deviation of temperature fits the ?1/3 law in the free convection limit, approaching a constant value within a stable limit. However, it exhibits hyperbolic characteristics for close to neutral stratification. The normalized standard deviations for humidity and CO₂ concentration exhibit scaling similar to the wind components in the unstable regime and remain constant in the stable domain. The results for the wind components and for temperature are in the range of various functions found in other studies. The absolute values for humidity and CO₂ concentration seem to be slightly higher, but only single examples of such investigations can be found in the literature.  相似文献   

The High-Resolution Coronal Imager (Hi-C)     

Ken Kobayashi  Jonathan Cirtain  Amy R. Winebarger  Kelly Korreck  Leon Golub  Robert W. Walsh  Bart De Pontieu  Craig DeForest  Alan Title  Sergey Kuzin  Sabrina Savage  Dyana Beabout  Brent Beabout  William Podgorski  David Caldwell  Kenneth McCracken  Mark Ordway  Henry Bergner  Richard Gates  Sean McKillop  Peter Cheimets  Simon Platt  Nick Mitchell  David Windt 《Solar physics》2014,289(11):4393-4412

The High-Resolution Coronal Imager (Hi-C) was flown on a NASA sounding rocket on 11 July 2012. The goal of the Hi-C mission was to obtain high-resolution (≈?0.3?–?0.4′′), high-cadence (≈?5 seconds) images of a solar active region to investigate the dynamics of solar coronal structures at small spatial scales. The instrument consists of a normal-incidence telescope with the optics coated with multilayers to reflect a narrow wavelength range around 19.3 nm (including the Fe xii 19.5-nm spectral line) and a 4096×4096 camera with a plate scale of 0.1′′?pixel^?1. The target of the Hi-C rocket flight was Active Region 11520. Hi-C obtained 37 full-frame images and 86 partial-frame images during the rocket flight. Analysis of the Hi-C data indicates the corona is structured on scales smaller than currently resolved by existing satellite missions.  相似文献