High-latitude dust deposition in snow on the glaciers of James Ross Island,Antarctica     

Jan Kavan  Daniel Nývlt  Kamil Láska  Zbyněk Engel  Michaela Kňažková 《地球表面变化过程与地形》2020,45(7):1569-1578

High-latitude dust (HLD) depositions on four glaciers of James Ross Island (the Ulu Peninsula) were analysed. The deposition rate on the selected glaciers varies from 11.8 to 64.0 g m⁻², which is one order of magnitude higher compared to the glaciers in Antarctica or elsewhere in the world. A strong negative relationship between the sediment amount and altitude of a sampling site was found. This is most likely caused by the higher availability of aeolian material in the atmospheric boundary layer. General southerly and south-westerly wind directions over the Ulu Peninsula – with exceptions based on local terrain configuration – help to explain the significantly lower level of sediment deposition on San Jose Glacier and the high level on Triangular Glacier. X-ray fluorescence (XRF) spectrophotometry was used to estimate the relative proportions of the main and trace (lithophile) elements in the sediment samples. Both the sediment amount and the XRF results are analysed in a depth profile at each locality and compared among the glaciers, suggesting long-range transport of fine mineral material from outside James Ross Island. The distribution of aeolian sediment among the glaciers corresponds well with the prevailing wind direction on the Ulu Peninsula. © 2020 John Wiley & Sons, Ltd.  相似文献   

Carbonate inclusions in Lower Cretaceous picrites from the Hončova hůrka Hill (Czech Republic,Outer Western Carpathians): Evidence for primary magmatic carbonates?     

Kamil Kropáč  Zdeněk Dolníček  David Buriánek  Tomáš Urubek  Vlastimil Mašek 《International Journal of Earth Sciences》2015,104(5):1299-1315

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Late Miocene to Early Pliocene blueschist from Taiwan and its exhumation via forearc extraction          下载免费PDF全文

Sascha Sandmann  Thorsten J. Nagel  Nikolaus Froitzheim  Kamil Ustaszewski  Carsten Münker 《地学学报》2015,27(4):285-291

Blueschist facies rocks in the Yuli Belt of Taiwan's Central Range record ongoing subduction of the Eurasian plate. We present a prograde Lu–Hf garnet–whole‐rock age of 5.1 ± 1.7 Ma from a retrogressed blueschist in the Yuli Belt. This age is considerably younger than the previously assumed age of 14–8 Ma for high‐pressure metamorphism in the Yuli Belt and represents the youngest Lu–Hf garnet age ever recorded for blueschist facies metamorphism. The age sheds new light on the palaeogeographic origin and exhumation scenario of the Yuli Belt. We propose that the Yuli Belt originated from the ocean–continent boundary of the Chinese passive margin. It was subducted eastward during collision with the Luzon island arc and rapidly exhumed when the forearc lithosphere was removed from above the continental slab by discrete subduction (extraction). This process reduces the pressure above the continental slab and may prompt the ascent of subducted crust into the opening gap. Thus, it can control the exhumation of high‐pressure rocks.  相似文献   

Determinants and constraints of integrating natural acacias into mechanised rain-fed agricultural schemes Sennar State,Sudan     

Mustafa Kamil Mahmoud Fahmi  Elamin Sanjak Mohamed  Markku Kanninen  Olavi Luukkanen  Fobissie Blese Kalame  Abdalla Mirghani Eltayeb 《GeoJournal》2015,80(4):555-567

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Dynamic analysis of a vertical plate exposed to breaking wave impact     

M. Salih Kirkgoz  A. Kamil Tanrikulu  Cengiz Dündar 《Ocean Engineering》2004,31(13):2308-1635

From the experimental studies in recent years, it has become known that when a wave breaks directly on a vertical faced coastal structure, high magnitude impact pressures are produced. The theoretical and experimental studies show that the dynamic response of such structures under wave impact loading is closely dependent on the magnitude and duration of the load history. The dynamic analysis and design of a coastal structure can be succeeded provided the design load history for the wave impact is available. Since these types of data are very scarce, it is much more convenient to follow a method which is based on static analysis for the dynamic design procedure. Therefore, to facilitate the dynamic design of a vertical plate that is exposed to breaking wave impact, a multiplication factor called “dynamic magnification factor” is herein presented which is defined as the ratio of the maximum value of the dynamic response to that found by static analysis. The computational results of the present study show that the dynamic magnification factor is a useful ratio to transfer the results of static analysis to the dynamic design of a coastal plate for the maximum impact pressure conditions of p_max/γH₀≤18.  相似文献   

Properties,durability and use of glauconitic Godula sandstones: a relatively less known building stone of the Czech Republic and Poland     

Martin Vavro  Leona Vavro  Petr Martinec  Kamil Souček 《Environmental Earth Sciences》2016,75(22):1437

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Investigation of the effect of aggregate shape and surface roughness on the slake durability index using the fractal dimension approach     

Ersin Kolay  Kamil Kayabali   《Engineering Geology》2006,86(4):271-284

Argillaceous rocks cover about one thirds of the earth's surface. The major engineering problems encountered with weak- to medium-strength argillaceous rocks could be slaking, erosion, slope stability, settlement, and reduction in strength. One of the key properties for classifying and determining the behavior of such rocks is the slake durability. The concept of slake durability index (SDI) has been the subject of numerous researches in which a number of factors affecting the numerical value of SDI were investigated. In this regard, this paper approaches the matter by evaluating the effects of overall shape and surface roughness of the testing material on the outcome of slake durability indices.

For the purpose, different types of rocks (marl, clayey limestone, tuff, sandstone, weathered granite) were broken into chunks and were intentionally shaped as angular, subangular, and rounded and tested for slake durability. Before testing the aggregate pieces of each rock type, their surface roughness was determined by using the fractal dimension. Despite the variation of final values of SDI test results (values of I_d), the rounded aggregate groups plot relatively in a narrow range, but a greater scatter was obtained for the angular and subangular aggregate groups. The best results can be obtained when using the well rounded samples having the lowest fractal values. An attempt was made to analytically link the surface roughness with the I_d parameter and an empirical relationship was proposed. A chart for various fractal values of surface roughness to use as a guide for slake durability tests is also proposed. The method proposed herein becomes efficient when well rounded aggregates are not available. In such condition, the approximate fractal value for the surface roughness profile of the testing aggregates could be obtained from the proposed chart and be plugged into the empirical relation to obtain the corrected I_d value. The results presented herein represent the particular rock types used in this study and care should be taken when applying these methods to different type of rocks.  相似文献   

Graben width controlling syn-rift sedimentation: the Palaeogene southern Upper Rhine Graben as an example     

Sebastian Hinsken  Kamil Ustaszewski  Andreas Wetzel 《International Journal of Earth Sciences》2007,96(6):979-1002

Eocene to Early Oligocene syn-rift deposits of the southern Upper Rhine Graben (URG) accumulated in restricted environments. Sedimentation was controlled by local clastic supply from the graben flanks, as well as by strong intra-basinal variations in accommodation space due to differential tectonic subsidence, that in turn led to pronounced lateral variations in depositional environment. Three large-scale cycles of intensified evaporite sedimentation were interrupted by temporary changes towards brackish or freshwater conditions. They form three major base level cycles that can be traced throughout the basin, each of them representing a stratigraphic sub-unit. A relatively constant amount of horizontal extension (ΔL) in the range of 4–5 km has been estimated for the URG from numerous cross-sections. The width of the rift (L _f ), however, varies between 35 and more than 60 km, resulting in a variable crustal stretching factor between the bounding masterfaults. Apart from block tilting, tectonic subsidence was, therefore, largely controlled by changes in the initial rift width (L ₀). The along-strike variations of the graben width are responsible for the development of a deep, trough-like evaporite basin (Potash Basin) in the narrowest part of the southern URG, adjacent to shallow areas in the wider parts of the rift such as the Colmar Swell in the north and the Rhine Bresse Transfer Zone that delimits the URG to the south. Under a constant amount of extension, the along-strike variation in rift width is the principal factor controlling depo-centre development in extensional basins.  相似文献   

A mean behavior model of aerobic biodegradation in heterogeneous formation     

M. W. Kemblowski  C-M. Chang  I. Kamil 《Stochastic Environmental Research and Risk Assessment (SERRA)》1997,11(3):255-266

It has been observed that the field biodegradation rates for soluble hydrocarbon plumes are significantly smaller than the aerobic rates observed in the laboratory. It is believed that this difference is related to the fact that in the field oxygen and hydrocarbon must be mixed before the biodegradation reaction can occur, and that the effective degradation rate is controlled by the actual, not mean, concentrations of oxygen and hydrocarbon. In this work, we present a conceptual model of oxygen-mixing limited biodegradation, which indicates that the effective degradation rate should depend on the cross correlation between the oxygen and hydrocarbon concentration fluctuations. This is followed by a development of a rigorous, field-scale model.  相似文献   

Geochemical Atlas of the Slovak Republic at a scale of 1:1,000,000     

Kamil Vrana  Stanislav Rapant  Dušan Bodiš  Karol Marsina  Blanka Maňkovská  Ján ?urlík  Peter Šef?ík  Jozef Daniel  Ladislav Lu?ivjanský  Jaroslav Lexa  Silvester Pramuka 《Journal of Geochemical Exploration》1997,60(1):7-37

The Geochemical Atlas of Slovak Republic (49,036 km²) at a scale of 1 : 1,000,000 was compiled during 1991–1995 together with maps of associated geochemical and ecological features at a scale of 1 :200,000. Investigations were aimed at the evaluation of concentrations and distributions of Al, As, Ba, Be, Ca, Ce, Co, Cd, Cs, Cr, Cu, Fe, Ga, Hg, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, Sb, Se, Sn, Sr, Th, U, V, W, Y, Zn, Zr in groundwater (16,359 samples), stream sediments (24,422 samples), rocks (3839 samples), soils (9892 samples from 4946 profiles; A and C horizons of each profile were sampled) and forest biomass (the foliage of the forest tree species from 3063 plots was sampled). In groundwater field measurements of temperature, pH, conductivity, dissolved O₂, acidity, alkalinity were done. The evaluation was oriented to the natural radioactivity of the Slovak territory as follows: rocks (K, U, Th, U_tot and dose rate, 15,573 reference spectrometric points), radon risk and water (U_nat, ²²⁶Ra, ²²²Rn; 5271 samples). The main objective of the Geochemical Atlas was to construct single-component maps showing concentrations of chemical elements, compounds and measured parameters in the researched media of Slovakia at a scale of 1 : 1,000.000 and to create interactive databases of chemical composition and/or measured parameters of groundwater, biomass, rocks, soils, stream sediments and natural radioactivity, for the entire territory of the Slovak Republic. The single-component maps are not constructed in the part ‘Rocks’, where all the main rocks types of Slovakia are presented in the ‘Map of lithogeochemical rock types of Slovakia at a scale of 1: 500,000’. The edition of six atlases has been planned. In 1997 the first three atlases will appear (Groundwater, Biomass, Natural Radioactivity). Publishing of last three atlases (Rocks, Soils, Stream Sediments) is planned for 1998. Since the analytical works on stream sediments were finished during 1997, it was not possible to present here the results of that part of the Geochemical Atlas.  相似文献