Ten serwis zostanie wyłączony 2025-02-11.
Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 7

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  fluvial deposits
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
The analysis included alluvial sediments in the Łapszanka Stream valley in the Spisz area (Carpathians, Southern Poland). Seven gravel levels were distinguished in the sedimentary sequence, which is a record of periods of intense fluvial activity correlated with wet climate phases. They fall in the Early Holocene (10 100–8900 y BP), the beginning of the Middle Holocene (7900–6600 y BP), the Middle Holocene (6100–5900 y BP), the beginning of the Late Holocene (5100–4000 y BP), the Iron Age Cold Epoch, the Dark Ages Cold Period and the Little Ice Age. The gravels are separated by layers of mud, containing an abundant mollusc fauna. It was possible to distinguish five types of fauna assemblages corresponding to the environmental changes in the Spisz area during the Holocene. The malacofauna indicates that forests covered this area to a large extent during almost the entire period analysed. During the Early Holocene, the area was dominated by coniferous forests, and the fauna contained numerous cold-tolerant taxa. The Middle Holocene saw the emergence of mixed forests inhabited by mollusc communities that included species with high ecological tolerance. A malacofauna containing moisture-loving forest assemblages is characteristic of the sediments of the Late Holocene. The occurrence of muds (agricultural muds) with open-country snails at the top of the sequence indicates increased anthropogenic impact and associated deforestation during the last 500 years.
EN
This paper presents the results of absolute dating and biostratigraphical analysis carried out for alluvial sediments of an abandoned Starunia ozokerite mine located in the Velyky Lukavets River valley, in which large mammal remains were discovered in the first half of the 20th century. The sediments build up three terrace levels. The highest one, up to 8 m high (terrace II), is likely to be associated with a stage of aggradation, as well as with a short episode of valley broadening, which occurred in the Weichselian Late Pleniglacial. The lower one, 4 m high (terrace I), is most likely to be linked with the Holocene, despite a considerable transformation of its top due to mining activity. The lower part of this terrace cover bears coarse-grained channel sediments dated to 120.6-58.9 ka BP (Eemian Interglacial?-Early Pleniglacial - OIS 5e, 4 and 3), and overbank (distal floodplain) mud with intercalations of biogenic deposits (peat, peat mud and biogenic mud). The overbank deposits are dated to 48.2-11.11 ka BP (Glinde Interstadial?-Younger Dryas, OIS 3-2) and are overlain by Holocene (OIS 1) mud and biogenic deposits. In boreholes drilled in the vicinity of the present-day river channel, younger sediments occur more frequently. These include sediments originating from the Late Weichselian overlain by Holocene sediments. However, sediments originating exclusively from the Holocene are infrequent. The deposition of sediments took place in specific conditions of a permanent saturation of the environment with brine, petroleum and thickened bitumen. In the longest period of deposition (48.2-1.27 ka BP), ephemeral swamps, ponds and lakes were developed in different parts of the floodplain. They were marked by the presence of: Juncus glaucus/effusus, J. articulatus, Typha sp., Batrachium sp., Potamogeton filliformis, Bidens tripartita, Ranunculus sceleratus and Phragmites communis, as well as by halophytic species, like: Zannichellia palustris, Triglochin maritimum, Schoenoplectus tabernemontani, Puccinelia distans and Eleocharis palustris. Rhythmic oscillations between cold and warm climatic conditions, typical of the Weichselian age and well identified in Western Europe, are here marked by the changes of plant communities (woody assemblages passing into steppe and tundra), but are not noticeably recorded in the sediments of the Velyky Lukavets River. This shows that the greatest part of the discussed period involved the formation of poorly differentiated silty overbank sediments with intercalations of biogenic sediments. However, the variability of sediments provides evidence for extreme events which occurred in the Holocene.
|
2022
|
tom Vol. 66, No. 3
art. no. 23
EN
We describe the application of 2D ERT (electrical resistivity tomography) surveys to investigate the spatial complexity of fluvial deposits of the Wisła River valley in the eastern part of Kraków (southern Poland). All ERT survey lines were completed within the industrially influenced floodplain of the Wisła River at two research sites. Due to the transformation of the natural state of the environment through many years of industrial activity of the ArcelorMittal Kraków plant, some of the geomorphological elements analysed have been irretrievably transformed and hidden by anthropogenic accumulations such as waste landfills and engineering structures. Hence, many years of soil contamination have changed the primary resistivity characteristics of the subsurface. For this purpose, the measurement array applied combines standard arrays, i.e., Wenner-Schlumberger and Dipole-Dipole, which gave improved results (higher resolution) in comparison to the standard single array. The data interpretation method was supported by the calculation and visualization of the vertical and horizontal gradients of the interpreted resistivity within the resistivity sections. This approach allowed accurate determination of resistivity boundaries on the ERT resistivity sections and thus helped lithological interpretation of the fluvial deposits in the research area. The resistivity of water in a channel located within one of the analysed areas has impacted some of the research results. Furthermore, 2D ERT forward modeling was implemented to generate synthetic datasets. The synthetic data allowed investigation of the influence of groundwater contamination on the resistivity distribution within superficial layers, and also tested the ability of the 2D ERT model to recognize the detailed spatial distribution of palaeomeander (meander scar) infills. All methods have provided new information on the industrially influenced floodplain of the Wisła River in Kraków.
|
|
tom Vol. 24, No. 2
151--162
EN
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.
|
|
tom nr 435
47--56
PL
Praca została wykonana na podstawie badań chemicznych i badań litologicznych osadów z profili Sucha Wieś i Czarnucha. Oba profile są bardzo zbliżone do siebie pod względem litologii i zmian środowiska depozycji osadów. Cykl zmian sedymentacji jest zapisany od osadów klimatu borealnego do osadów jeziornych klimatu ciepłego oraz ponownie do osadów rzecznych i jeziornych klimatu borealnego.
EN
The work deals with chemical analyses and lithological studies of deposits from the Sucha Wieś and Czarnucha sections. Both these sections show much similarity in terms of lithologies and changes in sedimentary environments. The sedimentary record reveals a cycle of changes from a boreal climate to a temperate climate represented by lacustrine sediments and again towards a boreal climate with fluvial and lacustrine deposition.
EN
The heavy-mineral assemblages of Pleniglacial fluvial sediments were analysed for two river valleys, viz. the Luciąża River (at Kłudzice Nowe) and the Belnianka River (at Słopiec). These sites, on the Piotrków Plateau and in the Holy Cross Mountains respectively, are located in different morphogenetic zones of Poland that were affected to different degrees by the Middle Polish ice sheets. The study was aimed at determining the kind of processes that modified the heavy-mineral assemblages in the two fluvial sediments, at reconstructing the conditions under which these processes took place, and in how far these processes caused changes in the assemblages. The heavy-mineral associations of the parent material was taken as a starting point; this parent material were the sediments left by the Odranian glaciation (Warta stadial = Late Saalian). It was found that heavy-mineral assemblages in the Luciąża valley deposits are varied, particularly if compared with other fluvioglacial Quaternary deposits from the Polish lowlands, with a dominance of garnet. In the fluvial deposits of the Belnianka valley, zircon, staurolite and tourmaline dominate, with minor amounts of amphibole, pyroxene, biotite and garnet. This suggests that the deposits were subject to intensive and/or persistent chemical weathering and underwent several sedimentation/erosion cycles under periglacial conditions. In both valleys chemical weathering and aeolian processes were the main factors that modified the assemblages of the transparent heavy minerals; these processes were largely controlled by the climatic changes during the Pleistocene.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.