Geologos, 2014, 20, 1


Recent Submissions

Now showing 1 - 4 of 4
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    What are cleats? Preliminary studies from the Konin lignite mine, Miocene of central Poland
    (Wydawnictwo Naukowe UAM, 2014-03-31) Widera, Marek
    Cleats (fractures, joints) are discontinuities in coals, including lignites. They are important in mining activity because of their gas and water permeability in hard coal, and mainly because of their water permeability in lignites. As opposed to hard-coal cleats, lignite cleats have not been studied in detail before. The present contribution does so, using as an example the 1st Middle-Polish Lignite Seam (MPLS-1) in the Jóźwin IIB opencast mine in central Poland. It should be mentioned here that any remarks in the present contribution concerning MPLS-1 refer exclusively to this lignite seam in the Jóźwin IIB opencast mine. The investigated discontinuities consist of two sets, i.e. the face and butt cleats, which are roughly oriented NW–SE and NE–SW, respectively. The mean spacing of the face cleats is ~12.4 cm, while the mean spacing of the butt cleats is ~12.8 cm. The maximum average aperture is ~4.9 mm for the face cleats and ~4.1 mm for the butt cleats. The cleat spacing and aperture do not depend on the lignite thickness, but the cleat spacing increases with increasing mineral-matter and xylite content, whereas the aperture increases when the contents decrease. The regional folding and local salt diapirism tentatively explain the formation of the orthogonal system of the lignite cleats, partly because of the parallelism of the face cleats and the major tectonic directions in central Poland.
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    Surface and subsurface reworking by storms on a Cambrian carbonate platform: evidence from limestone breccias and conglomerates
    (Wydawnictwo Naukowe UAM, 2014-03-31) Chen, Jitao
    Some limestone breccias and conglomerates from the Furongian (Late Cambrian) Chaomidian Formation (Shandong Province, China) were investigated in order to understand the depositional and deformational processes induced by storms. The sediments under study occur in a hummocky cross-stratified peloidal grainstone layer. The limestone conglomerates consist of well-rounded clasts that are mostly flat-lying or imbricated, and have erosional bases. They formed by surface reworking (erosion and rip-up) of thin-bedded grainstones by storm waves and currents. The lime -stone breccias consist of subangular to subrounded clasts of grainstone, which are often associated with small-scale grainstone clastic dykes. The breccias and dykes resulted from subsurface soft-sediment deformation (i.e., differential liquefaction and fluidization of heterogeneously cemented carbonate grains), most likely triggered by storm-wave load -ing. The limestone breccias and conglomerates bear important implications for understanding the reworking mecha -nisms of storms on ancient carbonate platforms.
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    Assessment of metal concentrations in tap-water – from source to the tap: a case study from Szczecin, Poland
    (Wydawnictwo Naukowe UAM, 2014-03-31) Górski, Józef; Siepak, Marcin
    The concentrations of Al, As, Cd, Cu, Pb, Zn, Ni, Fe and Mn were determined in June 2010 for 100 tap-water samples, collected directly at consumers in the older part of the city of Szczecin (Poland). Increased concentrations of metals were thus detected. This concerns mainly Fe (19% of samples showed concentrations above drinking-water quality standards) and Pb (5%). In some samples, the maximum admissible concentration levels for Mn, Cu and Ni were also exceeded. This was not the case for Al, despite the use of aluminium compounds during water treatment; the Al con -centrations in treated water were, however, significantly higher than in raw water. It was also found that (1) the corrosive properties of water (low alkalinity and increased concentration of sulphates), (2) the water-treatment processes causing a decrease of the pH and an increase of the CO 2 , and (3) transport of the treated water over long distances (30 km) provide favourable conditions for the leaching of metals from water-pipe networks. The type of material used in domestic plumbing and the content of Ce, Fe, Mn, Ni and Cd in the tap-water at consumers show a correlation. The high content of Pb is mainly a result of lead pipes connecting the network to the buildings.
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    The usefulness of ground-penetrating radar images for the research of a large sand-bed braided river: case study from the Vistula River (central Poland)
    (Wydawnictwo Naukowe UAM, 2014-03-31) Lejzerowicz, Anna; Kowalczyk, Sebastian; Wysocka, Anna
    Ground-penetrating radar (GPR) surveys and sedimentological outcrop analyses were combined in order to determine the reflection patterns and internal architecture of terrace deposits of the Vistula River at Kępa Zawadowska in the southern part of Warsaw (central Poland). The sedimentary analyses concerned the granulometric composition and lithofacies analysis. The 34 GPR profiles, which were obtained in two outcrops, using a Malå RAMAC/GPR system with 500-MHz and 250-MHz shielded antennas, were up to 100 m long. The most characteristic ground-penetrating radar profiles are presented; they show a high-resolution data set of radar facies. The GPR data suggest the presence of three geophysically different units, namely with high-angle inclined reflections (radar facies 1), with discontinuous undulating or trough-shaped reflections (radar facies 2), and with low-angle reflections (radar facies 3). The internal structure of the fluvial deposits was obtained by integration of the GPR and sedimentological data, which combination provides a more accurate visualisation of sedimentary units than do reconstructions that are based only on standard lithologic point data.
Uniwersytet im. Adama Mickiewicza w Poznaniu
Biblioteka Uniwersytetu im. Adama Mickiewicza w Poznaniu
Ministerstwo Nauki i Szkolnictwa Wyższego