Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 12

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

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
The Suchedniów water reservoir is located in the central section of the River Kamionka in the northern part of the Holy Cross Mountains of central Poland. This area once belonged to the Old Polish Industrial District that, during the Middle Ages, was very intensively developed by iron metallurgy. Many forges and mills along the rivers used water power, which led to the construction of an anthropogenic, small-scale water retention system. At the beginning of the twentieth century many of these reservoirs were drained after the collapse of metallurgical activities. The present-day reservoir was built in 1974 and drained in 2017. Research into the drained basin has documented various forms and sediments, some of which record present-day depositional processes (fire proof clay layer, inland fan delta), while others represent the historical period (lacustrine sediments of older reservoirs). Traces of catastrophic events have been preserved as well; an assemblage of megaripples marks the sudden drainage caused by a dam break in 1974.
EN
The fine-grained autochthonous sedimentation in the deep part of a Late Triassic lake was frequently interrupted by gravity-induced mass flows. Some of these mass flows were so rich in water that they must have represented slurries. This can be deduced from the soft-sediment deformation structures that abound in cores from these lacustrine deposits which constitute the Yanchang Fm., which is present in the Ordos Basin (central China). The flows and the resulting SSDS were probably triggered by earthquakes, volcanic eruptions, shear stress of gravity flows, and/or the sudden release of overburden-induced excess pore-fluid pressure. The tectonically active setting, the depositional slope and the high sedimentation rate facilitated the development of soft-sediment deformations, which consist mainly of load casts and associated structures such as pseudonodules and flame structures. Sediments with such deformations were occasionally eroded by slurries and became embedded in their deposits.
EN
The wooden structures unearthed in 2012 during archaeological excavation in the courtyard of the Museum of Archaeology and History in Elbląg have been dated using the dendrochronological method to the period between 1245 and 1302, which allows them to be considered to be parts of a Teutonic fortress. The remains of the wooden building located directly on the prehistoric lacustrine sediments created a unique opportunity to reconstruct the near-shore sedimentation of the Drużno Lake. Geological, malacological and palynological methods were applied during the investigation. The results, compared with the ranges of both the Drużno Lake and the Vistula Lagoon, known from previous studies of the region, allowed the correlation of a phase of a deep lake with the “Roman Period”. Rapid shallowing of the lake occurred in the “Migration Period”. The final disappearance of the lake in the area of modern Elbląg occurred in the early Middle Ages.
EN
The Kremna Basin is located in southwest Serbia, in the Zlatibor area, which is part of the Internal Dinarides. This basin is noteworthy because of the type of bedrock drainage, which it represents. It was formed on ultrabasic rocks and volcanic materials that influenced the occurrence of organic matter (OM) in the basin fill. The objective of the study was to determine the organic geochemical characteristics of sediments from the central part of the Kremna Basin. The sediments studied belong to an intrabasinal facies, in which two sequences were distinguished. The lower sequence occurs at depths of 216–343 m, while the upper sequence is found from 13.5–216 m. At the start of basin development (265–343 m) sedimentation took place in shallow alkaline water, rich in Mg ions. Through time, a slight deepening of the basin occurred. This was followed by chemical deposition of carbonates (216–265 m). The most important change in the sedimentary environment occurred with the formation of sediments marking the transition between the sequences (at about 200 m). Sediments from the lower sequence are characterized by the dominance of dolomite and magnesite. There are indications of volcanic activity, i.e. tuff layers and the presence of searlesite. The upper sequence is characterized by the prevalence of calcite and dolomite. The amounts of MgO, Na2O and B are higher in the lower sequence, whereas the CaO content is higher in the upper sequence. The sediments contain different amounts of immature OM (late diagenesis). Biomarker analysis shows diverse precursors of the sedimentary OM: methanogenic archaea, photosynthetic green sulfur bacteria (Chlorobiaceae), bacterivorous ciliates, various bacteria, both photosynthetic and non-photosynthetic, the green unicellular microalga, Botryococcus braunii race A (exclusively in the upper sequence) and terrestrial plants. The lower sequence contains lower amount OM, composed primarily of kerogen II/III and III types, indicating a higher contribution of the allochtonous biomass of land plants from the lake catchment, particularly in the lower part. The sediments of the upper sequence are enriched in autochthonous aquatic OM, which comprises mostly kerogen I, I/II and II types. The transition from the lower sequence to the upper one is associated with a decrease in pristane to phytane ratio, gammacerane index and content of C28 steroids, absence or significantly lower amount of squalane, absence of C24 and C25 regular isoprenoids, 8-methyl-2-methyl-2-(4,8,12-trimethyltridecyl) chroman and C30 hop-17(21)-ene. Pyrolytic experiments showed that the sediments of the upper sequence, rich in aquatic OM, at a catagenetic stage could be a source of liquid hydrocarbons. The values of hopane, sterane and phenanthrene maturation parameters indicate that through pyrolysis at 400°C the samples investigated reached a value of vitrinite reflectance equivalent of approximately 0.70%. It was estimated that the sediments should be found at depths of 2300–2900 m in order to become active source rocks. The calculated minimum temperature, necessary for catagenetic hydrocarbon generation, is between 103 and 107°C.
EN
Malacological studies of two profiles of the Holsteinian (Mazovian) Interglacial from eastern Poland – Roskosz and Wilczyn 1/12 – are presented. They are connected with the northern part of the Wilczyn palaeolake and seems to document palaeoecological changes in the part of the climatic optimum and the post-optimal period. Mollusc communities are typical of lake environs. The latter is supported by biometry of Pisidium moitessierianum. Higher energy conditions are evidenced by rheophile species P. henslowanum and P. nitidum in the lowermost part of the Roskosz section. Mollusc assemblages with Lithoglyphus jahni, with Valvata piscinalis and Bithynia tentaculata as well as with Valvata piscinalis are distinguished at Roskosz. They record changes in aquatic vegetation and depth conditions. Malacofauna from Wilczyn 1/12 is dominated by V. piscinalis, V. piscinalis f. antiqua and B. tentaculata. Limited contribution of temperate gastropods Viviparus diluvianus and L. jahni as well as the occurrence of some cold-loving forms indicate a deterioration of thermal conditions. Shallow-water habitats and expansion of reed zones are inferred from proportions of Bithynia shells and opercula.
PL
W odwierconych w latach 1988-1989 profilach otworów badawczych Sucha Wieś i Czarnucha, napotkano na organiczne i mineralne oraz rzeczne osady interglacjalne. Badania palinologiczne i litologiczno-petrograficzne tych osadów oraz datowania paleomagnetyczne określiły ich wiek na interglacjał augustowski (Augustovian), korelowany z Cromerianem I (Waardenburg). Przedstawiono stratygrafię i wiek osadów dolnego plejstocenu występujących w profilach Sucha Wieś i Czarnucha w nawiązaniu do innych profili położonych w obrębie Równiny Augustowskiej, Pojezierza Suwalskiego, Pojezierza Ełckiego oraz obszarów Rosji, Litwy i Białorusi.
EN
In the Sucha Wieś and Czarnucha boreholes drilled in 1988-1989, interglacial lacustrine and fluvial organic organic and mineral deposits were encountered. Palynological and lithologic-petrographical analyses and palaeomagnetic datings indicate that these deposits are of Augustovian Interglacial age, compared to Cromerian I (Waardenburg). This report shows the stratigraphy and age of the Lower Pleistocene deposits from the Sucha Wieś and Czarnucha sections with a correlation to other sections located in the Augustów Plain, Suwałki Lakeland, Ełk Lakeland and Russia, Lithuania and Belarus.
EN
This paper presents discussion on the results of subfossil Cladocera analyses from five lakes in Poland (Przedni Staw Lake, Perespilno Lake, Gościąż Lake, Imiołki- fossil lake and Ostrowite Lake). The Cladocera are represented in sediments by remains of planktonic (Bosminidae, Daphnidae) and littoral (Chydoridae) forms. Cladoceran assemblage phases ("ecostratigraphy") were determined on the basis of changes in dominance of indicator species and past ecological conditions were reconstructed. The results are being discussed from the viewpoint of climate change and anthropogenic activity and their role in the lake evolution. Moreover, an attempt to use the cladoceran phases for stratigraphic division of the Late Glacial and Holocene was made. During the Bolling/Allerod interstadial, distinguished on the basis of Pollen analysis, Cladocera indicated short phase of bad condition (dry or cold?), probably as the Old Dryas climate results. The beginning of Holocene are characterized, in mountain and lowland lakes, by high increase in the number of species and specimens of Cladocera. This described clear warming and marked the boundary Late Glacial/Holocene. It was indicated that the "ecostratigraphy" based on Cladocera can be useful for climatostratigraphy, if climate was the major factor controlling the development of freshwater lakes.
EN
Eemian Interglacial lacustrine sediments at Leszczyno are situated within the area of theWarta Glaciaton and slightly to the east from the maximal extent of the Vistulian Glaciaton. These sediments are situated in a wide depresion left by dead ice; its origin was controlled by tectonic and glaciotectonic conditions. Lacustrine silts and calcareus gyttja (about 2.7 m thick overlie the Warta Glacial till, and are covered by sands, silts and of the Vistulian Glaciaton (about 7.6 m thick). Palynostratigraphically, the biogenic lake sediments include 7 local pollen assemblage zones (L PAZ).Their spectra represent succession of the plant assemblages nearly of the whole protocratic stage, mesocratic stage and older segment of the telocratic stage of the Eemian Interglacial. Pollen diagram of the sediments from Leszczyno represents the north Masovian variant of the Eemian Interglacial succession, characterized by values of Abies (3%). Those of Taxus reach 5%.
EN
Ice sheet of the Wartanian Glaciation and their deposits shaped the landscape of the Węgrów Basin. Biogenic lake sediments at Porzewnica and Marysin sites (figs.1, 2) consist of about 5 m thick silts and gyttja, covered by 1.15 m thick sand at Porzewnica and by 8.5 m thick silts and sands at Marysin. In the Porzewnica pollen diagram (fig. 4) there are 7 L PAZ and 1 interzone without sporomorphs. representing vegetation succession during the late Wartanian Glaciation, the protocratic, mesocratic and part of the telocratic phases of the Eemian Interglacial. Spectra of sediments at the Marysin site represent 4 L PAZ of the youngest part of the mesocratic phase and fragments of the telocratic phase of that Interglacial.
10
Content available remote Fauna interglacjału ferdynandowskiego z Podgórza koło Wyśmierzyc nad Pilicą
EN
The profile of the borehole Podgórze B1, which at first was reconed among the Mazovian Interglacial was revealed by palynological analyses to represent the Ferdynandów Interglacial. Additional paleozoological studies confirmed presence of diverse faunal remains: Ostracoda, Pisces, Mollusca and Coleoptera, which allow to better recognize the character of environment of the interglacial sediments in Podgórze.
11
Content available remote Palaeoecology of basins of organic sediment accumulation in the Reserve Dury
EN
The Reserve Dury, Tuchola Pinewoods, Poland, includes five depressions with no outflow filled up with biogenic sediments. They undergo terrestrialization processes to a high degree. In four of the basins there are still some open water areas surrounded by floating mire with raised and transitional bog plants. For the needs of protection service officers some palynological and geological research were carried out. All the geological cores were described in detail following the Troels-Smith system. The deepest core Dury I was selected for pollen analysis. Ten Local Pollen Assemblage Zones (L PAZ) show the history of regional and local plant communities. On the basis of two air photographs, modern dynamics of floating mire in four basins were evaluated. The results allow us to correlate the geological layers, to describe the Late Glacial and Holocene succession of plant cover at Dury I site, and to show the stages of filling-in of basins with lacustrine sediments and peat.
EN
Sandy sediments of various origin and age dominate Quaternary geologic structure of the Odra Bank region. Three sediment series identified in numerous borehole section and dated using rediocarbon method represent sediments of the Interpleniglacial, the late Vistulian Glaciation, and the Holocene. The oldest series composed of sands, locally silty sands with organic matter and coalified organic remains, formed in the Interpleniglacial of the Vistulian Glaciation. Younger series is represented by the marshy-lacustrine sediments, which formed in the late Glacial and the Early Holocene. The youngest series is composed of marine sands. Stages of the region development were determined based on results of radiocarbon dating. Two dates are the most significant: 14 060 years BP, which indicates beginning of the peat accumulation in the studied region, and 5190 years BP, which indicates the beginning of the Littorina Sea transgression into the Odra Bank.
PL
W budowie geologicznej czwartorzędu rejonu Ławicy Odrzanej przeważają osady piaszczyste różnej genezy i wieku. Trzy serie osadów rozpoznane w licznych profilach wierceń i datowane metodą radiowęgla, reprezentują osady interpleniglacjału i późnego glacjału zlodowacenia wisły oraz holocenu. Seria 1, zbudowana z piasków, miejscami z domieszką mułków, z rozproszoną substancją organiczną i zwęglonymi szczątkami organicznymi, występuje na północnym stoku Ławicy Odrzanej pod cienką pokrywą piasków morskich. Na podstawie datowań metodą radiowęgla seria ta została uznana za osady interpleniglacjalne utworzone prawdopodobnie w środowisku rzecznym. Rozpoznany na obecnym etapie badań tylko strop warstwy - maksymalnie do głębokości 6 m - nie daje podstaw do rozważań paleogeograficznych . Pojedyncze stanowiska z małżoraczkami i brak okrzemek w osadach dodatkowo utrudniają jednoznaczne określenie genezy osadów i środowiska sedymentacji. Seria 2 złożona z piasków i piasków mulistych, miejscami z torfem lub kredą jeziorną, rozpoznana została między Ławicą Odrzaną a brzegiem morskim i lokalnie na północnym skłonie ławicy. Bagienno-jeziorne osady tej serii wypełniają zagłębienia w powierzchni glin zwałowych. Datowanie radiowęglowe osadów dokumentuje okres tworzenia się torfów i rozwój jezior od późnego glacjału aż do transgresji morza litorynowego w okresie atlantyckim. Szczególne znaczenie dla paleogeografii i historii rozwoju obszaru w tym okresie mają daty 14060ą220 i 5100ą200 lat BP - najstarsza i najmłodsza data radiowęglowa osadów serii 2 . Pierwsza z dat, uzyskana dla najniższej próbki torfów w profilu świadczy o bardzo wczesnej deglacjacji tej części Bałtyku. Druga wyznacza schyłek lądowego okresu rozwoju Ławicy Odrzanej. Kolejną serię 3 budują holoceńskie piaski morskie z licznymi odsypami muszlowymi i lokalnymi koncentracjami minerałów ciężkich. Pokrywa piasków morskich najlepiej rozwinięta jest w najpłytszych rejonach dna. Jest to przede wszystkim Ławica Odrzana oraz jej przedłużenie w kierunku południowo-wschodnim - relikt brzegu mierzejowego. Data radiowęglowa 5190ą130 lat BP, uzyskana dla skorupek małżów morskich wyseparowanych ze spągowych partii morskiej pokrywy piaszczystej w profilu, dokumentująca obecność morza u południowych zboczy bariery mierzejowej Ławicy Odrzanej, pozostaje w ścisłym związku z wcześniej wspomnianą datą wyznaczającą schyłek rozwoju jezior na ławicy. Istotne znaczenie mają też współczesne daty (młodsze niż tysiąc lat) muszli z warstwy erozyjnej leżącej w stropie osadów zaliczonych do interpleniglacjału. Dokumentują one współczesny etap rozwoju obszaru odznaczający się ograniczoną akumulacją osadów morskich i erozją płytko zalegających osadów starszych.
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.