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  • Author: Tomasz Zieliński x
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Unusual development of sandur sedimentary succession, an example from the Pleistocene of S Poland

An atypical lithological development of outwash deposits in the Carpathians Foreland (S Poland) shows lower and middle parts of the sedimentary succession that are characterized by sinuous palaeochannels. This channel facies consists of laterally accreted sands derived from side bars. The sedimentary environment was a proglacial system of anabranching channels, presumably of anastomosed type. The outwash channel pattern was most probably controlled by the raising base level of the fluvial system. Both proglacial and extraglacial waters were dammed by a sandur within a small upland valley. Aggradation and progradation of the glaciofluvial deposits resulted in progressive rising of the dammed lake level. The low hydraulic gradient of the outwash streams resulted in a sinuous planform as well as a low-energy style of deposition. Afterwards, the rising lake water was drained off through a low watershed and the entire valley became filled with outwash sediments. The bedrock morphology thus became buried and a typical unconfined sandur with a braided channel network developed during the last phase of the glaciomarginal sedimentation (upper part of the sedimentary succession under study).

Abstract

Systemic risk is a fundamental constituent of contemporary financial systems. For the past decades a growing number of abrupt upsets in financial systems could be observed. Due to previous experiences, politicians and regulators prefer to identify the offenders outside the system or to blame one of the entities inside the system. However, nowadays many disasters in anthropogenic systems cannot be perceived that way. They are often results of inappropriate interactions rather than external or internal impulses. This requires a paradigm shift in thinking about systemic risk. A component-oriented perspective should be nowadays replaced with a network-oriented view. Closer insight into the concept of systemic risk can refer to the model of the system composed of a huge number of interconnected components. In such a system, systemic risk is usually considered to have a ‘cascading’, ‘domino’ or ‘contagion’ effect, resulting from strong connections. An initial failure could have disastrous effects and cause extreme damage as the number of network nodes goes to infinity. Strongly interconnected, complex dynamic systems cannot be understood by the simple sum of their components’ properties, in contrast to loosely coupled systems. What makes the behaviour of complex financial systems particularly unpredictable is that systemic failures may occur even if everybody involved is highly skilled, highly motivated and behaving properly.

Abstract

Five parallel channels of the Narew River (NE Poland) were hydromorphologically assessed with the River Habitat Survey (RHS) method. Four out of the five studied channels were partly separated from the functioning system of the anastomosing river by a dike for more than 20 years, and were subjected to gradual overgrowing and shallowing. In the 1990’s and in 2002, a number of renaturisation measures were implemented, restoring sufficient discharge for the channels to make them active again. The Habitat Modification Score (HMS) obtained as a result of the survey only classifies the fragment ecologically to the third class of streams with high HMS value in the case of the current main channel of the Narew River (largely formed in an artificial manner). This suggests substantial anthropogenic changes in the river channel and its vicinity. The aggregate values of the Habitat Quality Assessment (HQA) index suggest the preservation of numerous environmentally valuable elements at all of the five studied sites of the anastomosing Narew River system. This even concerns channels which remained almost separated and functioned as oxbow lakes for more than 20 years. The highest HQA values were recorded in the case of the channel constituting the main channel before the regulation, and a neighbouring regulated channel currently fulfilling the function of the main water course in this cross-section. In spite of long-term negative changes, the studied fragment of the ecosystem of the anastomosing river is distinguished by high resistance to “anthropogenic stress”, and high capacity for spontaneous restoration of a state close to the natural one. Although lotic ecosystems constitute elements of the natural environment particularly sensitive to anthropopressure, they retain the ability to regenerate for a long time, under the condition of providing them with relevant hydrological and ecological conditions.

Sedimentary record of a Pleistocene ice-sheet interlobate zone (NE Poland)

Well developed NE-SW trending corridors of outwash in NE Poland are associated with a series of lakes with a similar direction of elongation. The glaciofluvial corridor under study consists of parallel ridges with associated channels and kames. The deposits are flanked by till and hummocky terrain. The gravel ridges are composed of sand and gravel deposits that are cross-stratified, massive or graded, and that contain cut-and-fill structures and large intra-clasts of sand and gravel. Locally the deposits show normal faults. The succession of one of the ridges is interpreted to reflect the infilling of a braided channel in a crevasse. Sedimentation took place in some phases when the ice-sheet regime changed from active to stagnant. Sandy-gravel ridges occur within this complex perpendicular to the Weichselian ice-sheet margin.

The corridor is interpreted as an interlobate area in the zone between the Warmia and Mazury ice lobes. The braided-channel deposits are not comparable to typical Polish sandurs. The lithofacies characteristics show higher energy conditions, and the channels are deeper than those typical of Pleistocene lowland sandurs. The sand and gravel ridges are interpreted as interlobate eskers.

Abstract

The present study revolves around the identification of the stratigraphical boundary between Pleistocene formations that formed prior to the first advance of the Scandinavian ice sheet (Early Pleistocene, i.e., the so-called preglacial) and the overlying, glacially derived deposits (Middle Pleistocene). In particular, it focuses on variation in heavy mineral assemblages, which are an important tool for stratigraphers. The Neogene basement, described here, was most often the source of material that was redeposited by Early Pleistocene rivers. The geological structure and Early Pleistocene palaeogeographical scenarios for various Polish regions are discussed. Moreover, comparisons with other European preglacial formations are carried out. The mineral spectrum of Lower Pleistocene deposits is largely dependent of rocks of the Neogene and Mesozoic basement. If the incision of ancient catchments was into terrigenous rocks, the stratigraphical boundary between preglacial and glacial formations is easily determined with the help of a heavy mineral analysis. As a rule, this coincides with a noticeable change from resistant to non-resistant mineral associations. Such cases are noted for successions in central Poland and eastern England. On the other hand, outcrops of igneous or metamorphic rocks exist within preglacial river catchments in most parts of Europe. They were the local sources of non-resistant heavy minerals long before their glacial supply from the Baltic Shield. In these cases, mineralogical analysis fails in the search for the Early/Middle Pleistocene transition.

Juvenile Blackbird (Turdus merula) moulting primaries and secondaries

Abstract

Deposits formed between the Neogene/Pleistocene transition and into the Early Pleistocene have been studied, mainly on the basis of drillings and at rare, small outcrops in the lowland part of Polish territory. At the Bełchatów lignite mine (Kleszczów Graben, central Poland), one of the largest opencast pits in Europe, strata of this age have long been exposed in extensive outcrops. The present paper is based on our field studies and laboratory analyses, as well as on research data presented by other authors. For that reason, it can be seen as an overview of current knowledge of lowermost Pleistocene deposits at Bełchatów, where exploitation of the Quaternary overburden has just been completed. The results of cartographic work, sedimentological, mineralogical and palynological analyses as well as assessment of sand grain morphology have been considered. All of these studies have allowed the distinction of three Lower Pleistocene series, i.e., the Łękińsko, Faustynów and Krzaki series. These were laid down in fluvial environments between the end of the Pliocene up to the advance of the first Scandinavian ice sheet on central Poland. The following environmental features have been interpreted: phases of river incision and aggradation, changes of river channel patterns, source sediments for alluvia, rates of aeolian supply to rivers and roles of fluvial systems in morphological and geological development of the area. The two older series studied, i.e., Łękińsko and Faustynów, share common characteristics. They were formed by sinuous rivers in boreal forest and open forest environments. The Neogene substratum was the source of the alluvium. The younger series (Krzaki) formed mainly in a braided river setting, under conditions of progressive climatic cooling. Over time, a gradual increase of aeolian supply to the fluvial system can be noted; initially, silt and sand were laid down, followed by sand only during cold desert conditions. These fluvio-periglacial conditions are identified in the foreground of the advance of the oldest ice sheet into this part of central Poland. The series studied have been compared with other fluvial successions which accumulated in the Kleszczów Graben during subsequent glaciations so as to document general changes in fluvial systems as reactions to climatic evolution. Thus, a palaeoenvironmental scenario has emerged which could be considered to be characteristic of central Poland during the Early Pleistocene.

Abstract

The combat-trainer jet aircraft is an important element in the process of fighter pilot training. This type of aircraft provides a means of transition from basic training on low-speed propeller trainers to piloting high-speed and highly maneuverable fighter aircraft. Nowadays, in Poland, the PZL TS-11 “ISKRA” jet trainers, designed in 1960s, are employed for training purposes. Because of financial considerations this trainer hasn’t been yet replaced by modern aircraft that conforms to current specifications and needs.

As is the case with other aircraft in service of the PLAF, the TS-11 fleet has a large reserve of remaining Hourly Service Life (HSL). This opens an opportunity to extend the Calendar Service Life (CSL), so as it matches the HSL. To this end, a series of technical and research activities needed to be undertaken. The Air Force Institute of Technology is conducting the necessary verification of airframe structural conditions in cooperation with the Military Aviation Works No. 1 J.S.C. (branch in Dęblin) responsible for the overhaul and repair operations.

The AFIT’s activities in this program include:

  • deformation analysis of the selected surface areas of the wing and the fuselage;
  • assessment of hidden corrosion in riveted joints;
  • non-destructive testing of selected riveted joints.

This paper describes the deformation analysis. As of today, the first stage of the deformation inspection has been completed. At this stage, baseline surface measurements were obtained. Further inspections shall be performed cyclically. The future measurements will be used to establish the areas that deform due to the aircraft operation.

Abstract

Geostatistical methods for 2D and 3D modelling spatial variability of selected physicochemical properties of biogenic sediments were applied to a small valley mire in order to identify the processes that lead to the formation of various types of peat. A sequential Gaussian simulation was performed to reproduce the statistical distribution of the input data (pH and organic matter) and their semivariances, as well as to honouring of data values, yielding more ‘realistic’ models that show microscale spatial variability, despite the fact that the input sample cores were sparsely distributed in the X-Y space of the study area. The stratigraphy of peat deposits in the Ldzań mire shows a record of long-term evolution of water conditions, which is associated with the variability in water supply over time. Ldzań is a fen (a rheotrophic mire) with a through-flow of groundwater. Additionally, the vicinity of the Grabia River is marked by seasonal inundations of the southwest part of the mire and increased participation of mineral matter in the peat. In turn, the upper peat layers of some of the central part of Ldzań mire are rather spongy, and these peat-forming phytocoenoses probably formed during permanent waterlogging.

Abstract

The growth of lactic acid bacteria during liquid-state fermentation of buckwheat flour and changes in pH during the process were analyzed. Eight strains of Lactobacillus were selected as the most active strains used to obtain new fermented flours. Physical properties of buckwheat water biscuits formulated from these fermented flours were studied.

The hardness of freshly prepared biscuits was affected by the lactic acid bacteria applied, with its highest value noted for the water biscuits made of buckwheat flour fermented by L. plantarum IB. Significantly greater differences in hardness values of water biscuits were noted after 24 h storage. Moreover, water biscuits made of the fermented flours were lighter and had a higher browning index as compared to the control biscuits prepared from unfermented buckwheat flour. The obtained results demonstrate the feasibility of selecting lactic acid bacteria for the fermentation of buckwheat flour focusing on some physical properties of the water biscuits.