Ograniczanie wyników
Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 75

Liczba wyników na stronie
first rewind previous Strona / 4 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  Quaternary
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 4 next fast forward last
EN
According to the current state of research five sand-gravel accumulation levels of Quaternary age are visible in the morphology of the western part of the Holy Cross Mountains, within the Wierna Rzeka, Hutka and Bobrza river valley systems and the lower stretches of the Biała Nida and Czarna Nida river valleys. Two upper levels (V and IV) correspond to valleys formed during the Odranian Glaciation-Saalian, MIS6 and its reccesional phases under the influence of proglacial and extraglacial waters beyond the extent (to the east) of the maximal ice-sheet limit of this glaciation, reaching to the present-day Leśnica-Gnieździska-Łopuszno line. Two lower levels (III and II) are terraces that were typically formed during the climatic conditions thatprevailed during Vistulian stadials. Sands and gravels of the three upper levels (V−III) contain numerous debris flow deposits and cryoturbation structures documenting periglacial conditions during their accumulation. The lowermost level (I) is a typical Holocene floodplain.
EN
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.
EN
In areas experiencing low deformation rates, landscapes provide limited evidence of ongoing tectonic activity, being either masked or altered by exogenic processes. Accordingly, the identification of fault activity and near surface deformation is commonly accomplished by multidisciplinary research combining geological, geophysical and geomorphic methods. In this study, Quaternary fault activity in the SW Pannonian Basin is investigated in the region of Bilogora, NE Croatia. The study area is positioned along the SW margin of the Drava Depression that was uplifted during the Pliocene and Quaternary within the Drava Depression Boundary Fault Zone. In this fault zone six GPR profiles were recorded. Reflection patterns, radar facies and truncations determined fault activity and near-surface deformation at four locations with vertical displacements of ≤1 m. At two sites, profiles did not show truncation of the shallowest reflections, however, an elevation difference of ca. 10 m between two palaeostream channels along one of the profiles suggests Quaternary uplift accommodated by a mapped fault. Considering the importance of the seismogenic potential of active faults and their correlation with the seismicity of Bilogora, this research will be followed by additional studies of near-surface strata deformation and palaeoseismological fault properties.
EN
The possible existence of a circular structure in the Kościerzyna region (northern Poland) was suggested in two papers in the 1980s. The current studies were aimed at verifying this hypothesis. Analysis of a digital terrain model of the pre-Quaternary surface relief as well as of the present terrain revealed the existence of a large structure of ca. 50 km in diameter. Its geometry was established based on a model of the Neogene/Pliocene surface and identifiable lineaments. Its characteristic feature is the presence of rim-like forms, an internal plateau, and a “high” in the centre. The structure is estimated to date from before the Pleistocene. The circular structure has been reshaped by glacial erosion and accumulation, and is now buried under Quaternary deposits. The existence of the Kościerzyna circular structure was confirmed by conducted studies, but my hypothesis of an impact origin is still uncertain and needs to be confirmed by future research.
5
EN
This paper summarizes four years of geological research in the Pomerania Bay and Oder Bank. As a result of the synthesis of new and archival data,we have compiled maps, cross-sections and models depicting the geological structure of the Quaternary and its basement, and the relief of structural surfaces. Two main seismostratigraphic sedimentary complexes are distinguished. The first corresponds to Pleistocene glacial and interstadial deposits. The second one is composed of Late Glacial and Holocene lacustrine-swamp and marine sediments. The outline of geochemical condition of the sea bottom is also presented. The content of the elements is always below the acceptable concentration and the origin of the elements is geogenic. Special attention has been given to mineral resources on the bottom surface and to documenting deposits of sand containing heavy minerals. The characterization of areas with sands suitable for beach nourishment and valorization of deposits and prospective areas have also been of great importance. The history of the development of the geological structure and palaeogeography of the area is the summary of the results.
EN
The paper presents the results of new studies of Quaternary deposits filling the Kleszczów Graben in the Szczerców outcrop, Bełchatów Lignite Opencast Mine. Sedimentary successions were profiled in the fieldwork. Moreover, the borehole data were studied. Laboratory studies included: grain size analyses, analyses of shape and morphology of quartz grain (morphoscopy), analyses of anisotropy of magnetic susceptibility (AMS), palynological, malacological and ostracodological studies, as well as geochronometric (C14) and geochemical (δ18O/δ16O) measurements. The studies were carried out in 2009–2013 and resulted in discovering of some sedimentary formations as well as arranging geological cross-sections and synthetic lithostratigraphic profile. The following sedimantary formations have been distinguished: Folwark, Kuców, Czyżów, Ławki, Rogowiec, Aleksandrów, Piaski and Widawka, arranged into two structural units: the lower one – deformed, and the upper one – undeformed.
7
PL
W neogeńskich gipsach Niecki Soleckiej występują następujące typy form krasowych: duże obniżenia krasowo-denudacyjne, krasowe (ślepe) doliny, leje oraz liczne, choć niewielkie jaskinie, stanowiące pojedyncze lub słabo rozgałęzione korytarze bądź komory (głównie typu branchwork i rudimentary branchwork). Większość z tych form reprezentuje epigenetyczny kras odkryty, który rozwinął się w czwartorzędzie i nadal jest aktywny. Największe obniżenia krasowo-denudacyjne zaczęły powstawać prawdopodobnie już w późnym neogenie. Rozwój form krasowych Niecki Soleckiej, w tym większości jaskiń, w warunkach krasu epigenetycznego różni ten region od zachodniej Ukrainy, gdzie w gipsach neogeńskich występują wielkie labiryntowe systemy jaskiniowe powstałe w wyniku głębokich przepływów międzywarstwowych. Na terenie Niecki Soleckiej tylko pojedyncze jaskinie reprezentują kras międzywarstwowy powstały w warunkach freatycznych, poniżej napiętego zwierciadła wód podziemnych, prawdopodobnie w późnym neogenie.
EN
A variety of types of karst forms has been identified in Neogene gypsum of the Niecka Solecka (Solec Basin), including large karstic-denudational depressions, karst (blind) valleys, sinkholes, and numerous but short and simple (branchwork and rudimentary branchwork type) caves. Most of these forms represent the epigenic, exposed karst, that developed during the Quaternary and is still active. The largest karst-denudational depressions could have started to develop in the Late Neogene. The epigenic character of karst forms (and most of caves) in gypsum of the Niecka Solecka makes this region distinctive from Western Ukraine, where large maze cave systems representing intrastratal karst occur. In the Niecka Solecka region only a few caves represent intrastratal karst formed in confined, freatic conditions probably in the Late Neogene.
EN
The article shows the results of geophysical surveys performed by using Electrical Resistivity Tomography (ERT) method on selected ragion of Płock slope of a Tumski hill near Basilica of Assumption of the Blessed Virgin Mary in Płock and in Maszewo by the Vistula River a few kilometers north of Płock. The above-mentioned sections were selected due to landslide phenomena observed there. Geophysical surveys were conducted in order to verify the state of the distribution of electrical resistivity in the sectors where mass movement was identified. The electrofusion crosssection near Cathedral Basilica shows clays and sands. Also in ERT prospection a zone of loose soils with high resistance is clearly visible. The results of the ERT method from Maszewo, indicates historical land surface of a landslide and that the slope in Maszewo consists of cohesive deposits. In order to describe these particular issues, geological cross-sections and safety factor obtained by calculation are presented for the analyzed parts of the slope. The safety factor shows that probability of landslide activity near Cathedral Basilica is very unlikely and in Maszewo is very high.
EN
DC resistivity methods, soundings and Electrical Resistivity Tomography, were applied to study shallow geology in the place of planned construction of an experimental flood bank. The geoelectrical surveys provided quantitative information about the spatial presence of the various geoelectrical/geological layers: alluvial soils, sands, gravels and clays. ERT allowed maps to be constructed showing subsurface structure. A combination of geoelectrical and geological information resulted in a much better identification of the geological structure.
EN
The central (Paleozoic) and the south-western (Permian-Mesozoic) parts of the Holy Cross Mts. region are areas of typical structural morphology controlled by fold-type tectonic structure and lithology. In the northern (Mesozoic) marginal part of the region structural arrangement of main relief elements is not so clear due to the block-type tectonics, however, some morphological features, such as the valley network, elongation of glacial, kame-type landforms and orientation of rock cliffs are related to joint system. The general relief elements of part of the Nida Basin region adjoining the Holy Cross Mts. are of noeotectonic origin, while the subordinate landforms represent typical structural morphology. The role of recent tectonic factor should be also taken into account in the Holy Cross Mts., however, the identification of tectonic influence on the current relief of this region is very difficult.
EN
The aim of the study was to determine the maturity of organic matter in the Neogene sediments of the Orava-Nowy Targ Intramontane Basin and to estimate, according to vitrinite reflectance (Ro), maximum paleotemperatures affecting studied sediments. The area of research is located in southern Poland and northern Slovakia, on the boundary between the Inner and Outer Carpathians. The Neogene and Quaternary deposits, which are filling the basin, discordantly overlie folded strata of the Magura Nappe (Outer Carpathians), Podhale flysch (Inner Carpathians) and Pieniny Klippen Belt (Birkenmajer 1979). The analysis was performed on eleven miocene claystone and coal clay samples collected from four outcrops in Polish part of the basin and one outcrop in Slovak part of the basin. Microscope analysis of organic matter in reflected white light was carried out for each sample. Random reflectance of huminite was measured under oil immersion on randomly oriented grains using Zeiss Axioplan microscope in reflected monochromatic non-polarised light. The values of Ro were converted into paleotemperatures according to Barker & Pawlewicz (1986) equation. It was not possible to calculate paleotemepratures in ten samples due to low maturity of organic matter and to low carbonization degree of coal. Only for one claystone sample from Chochołów reflectance of vitrinite measurement was positive. The value of Ro for analyzed sample was 0.366%, which indicate paleotemeprature of about 25°C (early stadium of diagenesis). Previous analysis of the organic matter in the studied area was carried out by Nagy (1996). Comparison of the results of the measurements of the vitrinite reflectance in the mentioned article match the values described in this study. However the temperatures associated with the burial history proposed by Nagy (1996), do not correlate with the temperatures calculated from the equation of Barker & Pawlewicz (1986). Due to the temperature differences it is problematic to correspond with the burial history of studied area proposed by Nagy (1996).
EN
The occurrence of Pteridium spores - the common fire-adapted plant - was observed in Poland's Pleistocene (three interglacials and numerous interstadials) and Holocene pollen sequences. Until the onset of the middle Holocene, bracken was recorded relatively rarely. This marks climatic conditions with sporadic wildfires, followed by quick removal of the clones (or maintenance of the clones in a suppressed state) in the subsequent, post fire successional stages. In each interglacial we can also identify short periods (most often synchronous) of somewhat higher frequency of Pteridium, indicating a possible increase in natural fires as an effect of stormy conditions. These short periods are placed mainly within phases dominated by coniferous woodlands. The very high content of bracken found from a reanalysis of the long Saalian sequence at Ossówka as three regular culminations just above three non-tree phases, eastern Poland is the unique exception. To explain this we found the close modern analogue of the above phenomenon in the Alaskan region, at the boundary between the tundra and the boreal zone where in a very narrow forest zone, especially with the continental signature, lightning-initiated fires are very frequent (the edge effect). Pleistocene records of bracken during forest periods might indicate that thunderstorms and lightning strikes were responsible for its higher content. This is not to exclude the possibility that interglacial fires were set by Palaeolithic humans. However, it is more likely that the wildfires were utilized and to some extent controlled, especially at Ossówka, where the palaeolake existed for a long time after the interglacial; and this surely attracted the attention of game and humans. Our investigations show that rare, more abundant Pteridium in the Pleistocene sequences can be traced throughout the corresponding periods even at distant sites. This might be indirect evidence of a climatic pattern that promote stormy conditions and fires at that time. In the Holocene, different factors seem to be responsible for the long-term dynamics in Pteridium clones. Both in Poland and in adjacent areas bracken peaked in the middle Holocene from 8000 to 5000 BP, when this territory was occupied by deciduous woodlands. There is agreement that this is due to burning of forests by the hunter-gatherer societies of the Late Mesolithic. However, in spite of increased clearings in the subsequent phases bracken substantially decreased in abundance. This means first of all that fires rather than clearings were responsible for the rise in Pteridium spores in the Holocene pollen sequences.
EN
Several tufa complexes are known in the Slovak Karst which is a typical karst area of a temperate climate. This area is built of Mesozoic carbonates, mainly Triassic in age. The karst systems drain carbonate plateaux and lead water to resurgences located in valleys which are up to 300 m deep. Below the resurgences there are Holocene fossil tufa deposits that exceed 12 m in thickness. The tufas include stromatolite, moss, phytoclastic, oncoidal, and intraclastic facies. Extensive barrages which once dammed the upper reaches of the streams were formed in narrow valleys. They are composed predominantly of moss facies and stromatolites, with subordinate oncoidal and phytoclastic facies. Phytoclastic, oncoidal and intraclastic facies are dominant in dammed segments of streams, and include gastropod shells and charcoal fragments. Some small moss cushions are also developed. Barrages and dammed areas formed in a longitudinal fluvial depositional system. Conversely, below resurgences located on plateau slopes tufas of a perched springline depositional system were formed. These comprise deposits of prograding cascades constructed by moss, phytoclastic and stromatolitic facies. Presently, the tufas analysed are inactive. They stopped growing in the Late Holocene time, after which there was abrupt incision of the streams. This caused downcutting into Holocene tufas, in some places reaching Mesozoic bedrock. At present tufa is being precipitated from streams in all the sites studied.
PL
W pracy zostały rozpatrzone czynniki kształtujące środowisko hydrogeologiczne czwartorzędowego piętra wodonośnego na obszarze Górnośląskiego Zagłębia Węglowego. W rozważaniach uwzględniono wpływ zarówno czynników naturalnych, jak i działalności człowieka na środowisko wodne.
EN
The authors determined factors influencing the hydrogeological environment of the Quaternary aquifer in the Upper Silesian Coal Basin (USCB). The discussion includes both the impact of geological factors and human activity.
EN
In 21st century the chronostratigraphy of cave sediments is built on the basis of modern methods: sedimentological analysis, statistical analysis of palaeozoological data, radiometric and luminescence dating and many others. For the time of last 50 000 years the four geochronological units (or appropriate chronostratigraphic units) are usually proposed in Poland in the researches of cave sediments. They are: Interpleniglacial, Upper/Younger Pleniglacial, Late Glacial and Holocene. That scheme has over 150 years of evolution, and its origin was tied with biostratigraphical scheme built by Edouard Lartet in a middle of 19th century. Lartet's stratigraphy for the same period was also made of four units: Cave Bear Epoch, Mammoth and Wooly Rhinoceros Epoch, Reindeer Epoch and Auroch Epoch. Although basing on different methods and using different terminology, the two schemes – from the 19th and from 21st centuries – are similar and correlatabl
19
Content available Antropocen : nowa epoka geologiczna?
EN
The Anthropocene is a new epoch proposed by Crutzen and Stoermer (2000), with a base at 1950 AD or 1800 AD. The present author doubts its value while studying Quaternary stratigraphic columns, as its base signal (Holocene/Anthropocene) might be unrecognizable in field sections. The usage of the Anthropocene epoch would probably be restricted to areas of massive direct negative human impact on Nature, predominantly in the Northern Hemisphere. In much less affected Southern Hemisphere deserts (Australia), mountain chains (the Andes), the near-pristine glaciated Antarctic continent and Subantarctic islands, separation of the Anthropocene time-unit (as a formal epoch) from the Holocene epoch would be artificial, even useless. On the other hand, the informal term might be useful for economic geographers, planners, sociologists, and Nature- protectionists.
EN
Two types of large, branched structures from the Lower Pleistocene (Calabrian) high-energy calcarenites of Favignana Island are described: Faviradixus robustus gen. et sp. nov. and Egadiradixus rectibrachiatus gen. et sp. nov. They may be interpreted as root structures of large plants, trees and trees or shrubs, respectively. The former taxon co-occurs with the marine animal trace fossils Ophiomorpha nodosa, Ophiomorpha isp., Thalassinoides isp. and Beaconites isp. The interpretation as root structures although tentative is probable and can be related to short emergence episodes for the formation of E. rectibrachiatus or to longer emergence, responsible for the discontinuity at the base of the overlying Tyrrhenian deposits, for F. robustus. Calcified root mats of smaller plants associated with the Tyrrhenian or younger emergence surfaces are common.
first rewind previous Strona / 4 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.