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Wyszukujesz frazę "meandering" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Numerical modelling of rivers on Earth and Titan
Autorzy:
Misiura, K.
Czechowski, L.
Powiązania:
https://bibliotekanauki.pl/articles/2059637.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
titan
Earth
meandering river
erosion
sedimentation
Opis:
The differences in the evolution of rivers on Earth and on Titan are investigated. Dynamical analysis of the rivers was performed using a numerical package CCHE2D developed by the National Center for Computational Hydroscience and Engineering, University of Mississippi. The model is based on the Navier-Stokes equations for depth-integrated two-dimensional turbulent flow and the three-dimensional convection-diffusion equation of sediment transport. The model enables investigation of the evolution of rivers as a function of total discharge and other parameters of the river. Series of short (from one to several hours) and long (up to 67 days) simulations were performed. We have found that three different liquid hydrocarbons considered for Titan’s rivers give similar velocity fields. It was also found that the suspended load is the main means of transport in Titan’s rivers, while in terrestrial ones, for the same discharge, the bedload could be of the same order as suspended load. Moreover, we suppose that for specific boundary conditions, the evolution of rivers on the Earth promotes the development of braided rivers, while for the same conditions evolution on Titan favours regular meandering rivers
Źródło:
Geological Quarterly; 2015, 59, 3; 565--580
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
What was the interglacial river like? Sedimentological investigation of Holsteinian fluvial deposits in eastern Poland
Autorzy:
Zieliński, T.
Terpiłowski, S.
Zieliński, P.
Pidek, I. A.
Godlewska, A.
Czubla, P.
Powiązania:
https://bibliotekanauki.pl/articles/2060162.pdf
Data publikacji:
2016
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
sedimentology
meandering river
palaeoclimate
Pleistocene
MIS 11
Polska
Opis:
Holsteinian fluvial deposits in the Samica River valley in eastern Poland have been studied, in an approximately 12-m-thick succession filling palaeochannels and comprising sandy channel facies succeeded by a package of gyttja, peat and silt deposited in oxbow. Channel belts including palaeochannel fills cut into outwash sands and are overlain by diamictic sands reworked by solifluction under periglacial conditions. Sedimentological and palynological investigations in combination allowed the recognition of glacial and interglacial deposits. The channel belt was formed by a typical sand-bed, meandering river with deposition controlled by abundant point bars. The sedimentary evolution of the Samica valley is interpreted in the context of the glacial-interglacial cycle. Valley-scale erosion and change of river style from braided to meandering occurred coevally with the decay of an ice sheet (deglaciation) and the main phase of meandering river sedimentation is attributed to latest Elsterian and early Holsteinian. The next part of the interglacial, from pioneer stage to established temperate conditions, is recorded in a biogenic oxbow-lake fill. The succession studied has been compared with published data on the European fluvial deposits of Middle Pleistocene interglacials. It is pointed out here that river channel patterns in western and eastern Europe differed. Based on this observation, some general hypotheses regarding the continental-scale climatic distinctness are put forward.
Źródło:
Geological Quarterly; 2016, 60, 1; 149--166
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evidence for a very low-energy fluvial system: a case study from the dinosaur-bearing Upper Triassic rocks of Southern Poland
Autorzy:
Gruszka, B.
Zieliński, T.
Powiązania:
https://bibliotekanauki.pl/articles/2060617.pdf
Data publikacji:
2008
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Polska
Late Triassic
sedimentology
vertisol
meandering river
anastomosing river
Opis:
The Upper Triassic succession in S Poland in which dinosaur bones have been found consists predominantly of siltstones and claystones. Three units are distinguished. The lower most and the upper most units reflect an alluvial environment, whereas the middle one represents lacustrine facies. The lower alluvial unit is interpreted as a record of ephemeral, sinuous, suspended-load channels with rapid vertical accretion. Channel barforms are lack ing. The environmentis interpreted as a low-en ergy anastomosing fluvial system. The clayey middle unit is interpreted as having formed in a wide long-lived lake. The top of the lacustrine deposits shows signs of vertisol-type pedogenesis, most probably under subtropical conditions, with seasonally-inuced wet and dry intervals. The upper unit reflects a low-energy meander ingriver system. Silty point bars were abundant and the channels migrated freely. The energy level of this fluvial system was slightly higher than that of the earlier one, which is interpreted as an effect of base-level lowering in combination with an increasingly humid climate. The al most exclusively silty/clayey alluvial deposits represent an exceptionally rare facies. The drainage basin must have been an extremely flat lowland. The presence of vertebrate bones within the anastomosing and meandering river deposits indicates that low-en - ergy alluvial plains were apparently favourable habitats for both reptiles and amphibians during the Late Triassic: under the subtropical, seasonally dry conditions, the animals must have preferred moist lowareas, i.e. the flood basins and abandoned channels on the flat valley floors.
Źródło:
Geological Quarterly; 2008, 52, 3; 239-239
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zmiany układu koryta Chodelki koło Chodlika w późnym vistulianie i holocenie
Autorzy:
Dzierżak, Malwina
Bałaga, Krystyna
Powiązania:
https://bibliotekanauki.pl/articles/763309.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
meandering river
anastomosing river
lithofacies
palynological analysis
rzeka meandrująca
rzeka anastomozująca
litofacje
analiza palinologiczna
Opis:
In this paper the evolution of paleogeographic models of the middle part of the Chodelka valley near Chodlik is presented. In the relief of the bottom valley clear traces of palaeochannels are present. Lithological and palynological analysis helped distinguish two phases in the development of this river. The first phase started in Late Vistulian, and continued in the early Holocene. At that time Chodelka was an anastomosing river. But later it changed its channel pattern to the meandering one. Nowadays the Chodelka river cannot develop naturally, because its trough is largely limited by flood bank.
Artykuł nie zawiera abstraktu w języku polskim
Źródło:
Annales Universitatis Mariae Curie-Sklodowska, sectio B – Geographia, Geologia, Mineralogia et Petrographia; 2013, 68, 1
0137-1983
Pojawia się w:
Annales Universitatis Mariae Curie-Sklodowska, sectio B – Geographia, Geologia, Mineralogia et Petrographia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Natural and anthropogenic indicators of fluvial system changes, the Bobrza Valley (Holy Cross Mts) as an example
Autorzy:
Rutkiewicz, P.
Gawior, D.
Powiązania:
https://bibliotekanauki.pl/articles/100816.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Śląski. Wydział Nauk o Ziemi
Tematy:
meandering river
fluvial relief
sediments
human impact
Juncus subnodulosus
rzeka meandrująca
osad rzeczny
wpływ człowieka
Bobrza
Opis:
Transformations of a fluvial system are caused both by natural factors and human pressure. These factors model the system independently at different times and with different intensities or they affect it simultaneously. The aim of this study is to identify the transformation of the Bobrza river valley system occurring under natural conditions and that occurring under the influence of human activity. The identification was based on specific indicators The study was conducted in the valley mouth of the Bobrza River (Holy Cross Mountains), where three research sites were located. The investigation concerned the relief of the valley and the mineral and organic deposits. A wide range of research methods were used during the study e.g. analysis of LiDAR data, macronutrient analysis, and radioactive dating. The analyses enabled the natural and anthropogenic transformations of the Bobrza river system to be distinguished using the following indicators: morphometric and sedimentological characteristics of the palaeomeander (natural transformation), the sequence of mineral and organic deposits in exposures on the contemporary floodplain (natural and anthropogenic transformation) and transformation associated with the operation of a water mill (anthropogenic transformation). In addition, it is worth mentioning that the Bobrza channel is the location which has provided the only fossils of Juncus subnodulosus in south-east Poland.
Źródło:
Contemporary Trends in Geoscience; 2016, 5, 1; 46-60
2299-8179
Pojawia się w:
Contemporary Trends in Geoscience
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The sedimentary environment of Devonian siliciclastics in the Babí lom locality (Brunovistulian Platform cover, Southern Moravia, Czech Republic)
Autorzy:
Wojewoda, J.
Nehyba, S.
Gilíkova, H.
Burianek, D
Powiązania:
https://bibliotekanauki.pl/articles/2059824.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
southern Moravia
Brno Massif
Devonian siliciclastics
facies analysis
heavy minerals
alluvial fan
braided river
meandering river
palaeotransport
Opis:
Sandstones and conglomerates, which northwards of Brno agglomeration build a hill (ridge) named Babí lom are strongly diagenezed (anchi-metamorphozed) and tectonically deformed. Their regional distribution and stratigraphic position between the Cambrian(?) clastics and Upper Devonian limestones, as well as their appearance meant that they age is considering as Middle Devonian. They are distinguished as the so-called „Basal Devonian Clastics“. Almost all primary sedimentary features are well preserved and distinct. In the metasediments of the Babí lom hill were distinguished both the facies and structures typical of alluvial fans and rivers. Among others they are channel lags with imbricated grains, cross beddings and debrites. Within sedimentary association was established the way-up direction what clearly evidences a coarsening upwards sequence. Assuming the lack of rotation of series of sediments in the X-Y plane, the palaeotrasport was toward the north while major supply with material was from the east.
Źródło:
Geological Quarterly; 2015, 59, 1; 229--238
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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