Wyniki wyszukiwania - BazTech

1

New insights into the genesis of the “Poznań clays” – upper neogene of Poland

Maciaszek Piotr, Chomiak Lilianna, Urbański Paweł, Widera Marek

Civil and Environmental Engineering Reports

|

2020

|

Vol. 30, no. 1

18--32

EN

The present study focuses on the upper Neogene deposits, called the “Poznań Clays”, that cover more than 75,000 km2 of Poland. They are situated between the first midPolish lignite seam and the glaciogenic deposits of the Pleistocene age. Lithostratigraphically, the “Poznań Clays” belong to the uppermost portion of the lignite-bearing Grey Clays Member and the whole Wielkopolska Member (Poznań Formation). The examined fine-grained sediments include mud-rich floodplain deposits with palaeosol remnants and large sandy-muddy or muddy palaeochannel bodies. Therefore, taking into account facies analysis, cross-sectional geometry, and the planform of the palaeochannels, it can be stated that the “Poznań Clays” formed in the environment of a late Neogene anastomosing river.

2

The interpretative significance of ripple-derived sedimentary structures within an upper Neogene fluvial succession of central Poland

Maciaszek Piotr, Chomiak Lilianna, Wachocki Robert, Widera Marek

Geologos

|

2019

|

Vol. 25, No. 1

1--13

EN

Sedimentary structures discussed in the present study are genetically linked to ripples that consist of pure sand or alternating sand and mud layers. All types of ripple-related structures, such as climbing-ripple cross-lamination and heterolithic bedding, i.e., flaser, wavy and lenticular (nodular), have been identified for the first time in fluvial strata that have been characterised previously as commonly massive. These small-scale bedforms, produced by migrating ripples, have been documented in a fluvial channel of late Neogene age in central Poland. The abundance and co-occurrence of the structures discussed and their spatial distribution provide evidence of their formation under very low-energy conditions, when flow velocity changed markedly, but was often significantly less than 0.5 m/s. Therefore, these ripple-derived sedimentary structures are here recognised as typical of channel fills of an anastomosing river.

3

A Miocene anastomosing river system in the area of Konin Lignite Mine, central Poland

Widera M., Kowalska E., Fortuna M.

Annales Societatis Geologorum Poloniae

|

2017

|

Vol. 87, No. 2

157--168

EN

This sedimentological study of the Wielkopolska Member of the Miocene Poznań Formation in the Jóźwin IIB opencast lignite-mining field, central Poland, reveals a late mid-Miocene anastomosing fluvial system with ribbon-shaped channels filled mainly by sandy and muddy deposits. The fluvial system, extending across the eastern flank of the post-Mesozoic Kleczew Graben, was tributive in its eastern upper reaches, but was increasingly distributive and northwards deflected in its lower reaches near the graben axis. Lithofacies analysis of a representative palaeochannel indicates that the river discharge significantly fluctuated and that the channels were filled with mud-bearing stratified fine-grained sand by low-density tractional turbulent flow during the high and low water stages and with a massive mud or sandy mud by a high-density flow during the rising and falling stages. The spatial pattern of fluvial channels and deformation channel-fill sandbodies were controlled by the graben topography and the differential compaction of peat substrate, with possible influence of bedrock faults. The fluvial system is thought to have drained to an endorheic ‘terminal’ basin to the north, rather than into the hypothetical Baltic River and further westwards to the distant North Sea basin, as postulated by some previous authors. The present case study contributes to the known spectrum of anastomosing river systems as a sand- to mud-dominated end-member.

4

Evidence for a very low-energy fluvial system: a case study from the dinosaur-bearing Upper Triassic rocks of Southern Poland

Gruszka B., Zieliński T.

Geological Quarterly

|

2008

|

Vol. 52, No 3

239-239

EN

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.

5

Changes in the quality of river water and diversified character of the river channel: case study of the upper Narew River

Grabińska B., Koc J.

Journal of Water and Land Development

|

2005

|

no. 9

109-121

EN

The paper presents physicochemical and biological description of waters in the upper Narew River, within the Narew National Park demonstrating the differences in the water quality caused by the diversified character of the river channel and land use in the direct surrounding of the river. Changes in water quality were analysed based on water quality indices studied during five years (1997-2001). In the anastomosing section of the river the mean concentrations of: colour, organic suspended solids, BOD5, COD[sub]Mn, PO4 ³-, P[sub]org and chlorophyll a decreased by 11.6, 18.4, 25.0, 5.6, 8.0, 21.6 and 60,0%, respectively. A slight increase was observed in salinity, dissolved oxygen, ammonium nitrogen and nitrate nitrogen, which could be attributed to the water influx from the catchment. In the sampling site downstream the national park, where the Narew flows in an artificially profiled channel, all analysed parameters except for colour, pH and COD[sub]Mn increased. The quality of water in this section of the Narew is affected by the influx of heavily polluted waters from the Horowianka and more intensive human activities in the river valley and adjacent land. Mean values of BOD5, N-NO3, PO4 ³-, P[sub]org and salinity (but not Mg+²) in the water samples examined were significantly different one from another. In the natural, protected section of the river organic matter undergoes decomposition. The river waters according to BOD5 were classified two classes higher than outside the park. Low quality of water indicated by the value of COD along the whole length of the river implies that the water contains organic compounds that cannot be decomposed by microorganisms. These compounds originate from point sources.

PL

W pracy dokonano fizykochemicznego i biologicznego rozpoznania wód górnej Narwi, wykazując różnice cech wody wynikające ze zróżnicowanego charakteru koryta rzecznego oraz zagospodarowania terenów bezpośrednio do niego przyległych. Analizę zmian jakości wody przeprowadzono na podstawie średnich z pięciu lat (1997-2001) wartości wskaźników jakości wody. Stwierdzono, że w anastomozującym odcinku rzeki zmniejszyło się przeciętne stężenie PO4 ³-, P[sub]og i chlorofilu "a" wynosiło odpowiednio po 8,0; 21,6 i 60%. Wartości BZT5, ChZT[sub]Mn, zawartość zawiesin ogólnych oraz barwa kształtowały się następująco: 25,0; 5,6; 18,4 i 11,6. Wzrost dotyczył wszystkich wskaźników zasolenia, tlenu rozpuszczonego, azotu amonowego i azotanowego, co należy przypisać transportowi składników ze zlewni. W odcinku poniżej Parku, gdzie Narew płynie sztucznie wyprofilowanym korytem, odnotowano wzrost wszystkich przeciętnych wartości omawianych parametrów, oprócz barwy, pH i ChZT[sub]Mn. Wpływ na jakość wód Narwi na tym odcinku ma dopływ silnie zanieczyszczonych wód Horodnianką oraz wzrost oddziaływań gospodarczych w dolinie rzecznej i na terenach do niej przyległych. Średnie zawartości BZT5, N-NO3, PO4-³, P[sub]og i wskaźników zasolenia (oprócz Mg+²) różniły się istotnie statystycznie w badanych wodach. W chronionym odcinku rzeki dokonuje się biochemiczny rozkład substancji organicznych. Wody rzeczne ze względu na BZT5 kwalifikowały się o dwie klasy jakości wyżej niż poza Parkiem. Przeciętne wartości dla barwy, ChZT[sub]Mn i ChZT[sub]Cr odnotowane dla wód górnej Narwi 2-krotnie przewyższały wartości wymienionych wskaźników charakteryzujących wodę wiślaną. Niska jakość wody ze względu na ChZT na całym badanym odcinku wskazuje, iż zawiera ona pochodzące ze źródeł punktowych związki organiczne nierozkładalne przez mikroorganizmy.

6

In-channel accretionary macroforms in the modern anastomosing system of the upper Narew River, NE Poland

Gradziński R., Baryła J., Doktor M., Gmur D., Gradziński M., Kędzior A., Paszkowski M., Soja R., Zieliński T., Żurek S.

Annales Societatis Geologorum Poloniae

|

2003

|

Vol. 73, No 1

35-53

EN

Predomination of sandy bedload is typical of the anastomosing channels of the Narew River. Several types of in-channel accretionary macroforms have been found in these channels: side bars, concave-bank bars, plug bars, point bars, linguoid bars, and mid-channel bars. The first three types are relatively rare, point bars occur only exceptionally, while linguoid bars and mid-channel bars are quite common. The bars usually occur in main channels, which are the master routes of sand transport in the whole anastomosing system of the Narew. The lower parts of the bars are built of coarse- and medium-grained sand, similarly to the sediments in the deeper parts of the channels. Fine-grained sand, locally alternating with organic-rich muddy sand, predominates usually in the upper parts; peat with high content of sand is present in the highest parts of some bars. All bars are rapidly colonised and stabilised by plants. It is for this reason and due to the low energy of the river that the bar sediments have a high preservation potential. The development of bars is usually not accompanied by lateral migration of channels. Consequently, sediment accretion in bars is one of the factors leading to gradual narrowing of channels. Deposits of some sand-bars, when preserved in fossil record, may probably be represented by characteristic "wings" in the outer parts of ribbon-like sand bodies.

7

Anastomosing system of the upper Narew river, NE Poland

Gradziński R., Baryła J., Danowski W., Doktor M., Gmur D., Gradziński M., Kędzior A., Paszkowski M., Soja R., Zieliński T., Żurek S.

Annales Societatis Geologorum Poloniae

|

2000

|

Vol. 70, No. 3-4

219-229

EN

The studied section of the upper Narew river is an example of an anastomosing system. It consists of a network of interconnected channels and interchannel areas covered with peat-forming rush and reed vegetation. The channels have low longitudinal gradient, are laterally stable, relatively deep, they have sandy bed and strongly overgrown banks. There are no natural levees built of clastic sediment. Straight-type channels dominate in the channel system. Meandering reaches lack discernible point bar topography. Vegetation plays an important role in the evolution of the anastomosing system of the Narew.

PL

Badany odcinek Narwi jest przykładem systemu rzeki anastomozującej. Składa się on z sieci rozdzielających się i ponownie łączących się koryt oraz z obszarów pozakorytowych, porośniętych roślinnością torfotwórczą. Koryta mają mały spadek, są stosunkowo głębokie i lateralnie stabilne, a ich brzegi są silnie zarośnięte. Większość koryt ma stosunkowo niewielką krętość, ale podrzędnie występują także odcinki kręte, typu meandrującego, pozbawione jednak dostrzegalnych łuków przyrostowych, charakterystycznych dla topografii odsypów meandrowych. Brak jest wyraźnie rozwiniętych wałów przykorytowych zbudowanych z materiału klastycznego. Roślinność odgrywa znaczącą rolę w rozwoju omawianego systemu.