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Wyszukujesz frazę "lake sediment geochemistry" wg kryterium: Wszystkie pola


Wyświetlanie 1-4 z 4
Tytuł:
Geochemistry of surface sediments of a coastal Lake Sarbsko (northern Poland)
Autorzy:
Woszczyk, Michał
Cieśliński, Roman
Spychalski, Waldemar
Powiązania:
https://bibliotekanauki.pl/articles/2026076.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
coastal lake
lake sediment geochemistry
Gardno-Łeba Coastal Plain
southern Baltic
Polska
Opis:
The main goal of the pre sented re search was to in ves ti gate spa tial dis tri bu tion of sur face sed i ments and to rec og nize re la tion ships be tween chem i cal com po si tion of wa ter and sed i ments in a coastal Lake Sarbsko (north ern Po land). The Lake Sarbsko is a fresh wa ter ba sin. The wa ter col umn is well ox y gen ated and wa ters ex hibit only mi nor spa tial vari - abil ity of chem i cal com po si tion in di cat ing rapid and good mix ing. Sur face sed i ments of Lake Sarbsko are strongly di - ver si fied with re spect to chem i cal com po si tion. The sed i ments of Lake Sarbsko are char ac ter ized by el e vated con tent of terrigenous sil ica in di cat ing en hanced in put of clastic ma te rial from the wa ter shed and/or in creased dy nam ics of the lake wa ters. More over, SiO2ter is strongly neg a - tively cor re lated with SiO2biog, or ganic mat ter and el e ment con tents, which ar gues for di lut ing ef fect of the for mer to - wards authigenic com po nents of sed i ments. Ba si cally, terrigenous sil ica (quartz) con tent is high est in the lake shores and de clines to wards the lake cen ter. Biogenic sil ica, or ganic mat ter and most of el e ments dis play re versed ten dency. CaCO3 was en coun tered in three iso lated ar eas, where it co-oc curs with FeS. It is an tic i pated that pre cip i ta tion of cal - cite in Lake Sarbsko re sulted from postdepositional pro cesses. Spa tial dis tri bu tion of Fe, Mn, Ca, Mg, Na and K in Lake Sarbsko is also gov erned by their geo chem i cal af fin i ties to or ganic mat ter (Fe), Fe/Mn ox ides (Fe, Mn), sulphides (Fe), clay min er als (Na, K, Mg, Mn) and car bon ates (Ca, Mn).
Źródło:
Studia Quaternaria; 2009, 26; 41-53
1641-5558
2300-0384
Pojawia się w:
Studia Quaternaria
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Environmental changes during the last millennium recorded in subfossil Cladocera, diatoms and sediment geochemistry from Lake El Sol (Central Mexico)
Autorzy:
Zawisza, E.
Cuna, E.
Caballero, M
Ruiz-Fernandez, A. C.
Szeroczyńska, K.
Woszczyk, W.
Zawiska, I.
Powiązania:
https://bibliotekanauki.pl/articles/2060339.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
crater Nevado de Toluca
lake sediments
tropical alpine lake
palaeolimnology
last millennium
Opis:
High-altitude lakes, which are very sensitive ecosystems and respond rapidly to climatic changes, are one of the best targets for palaeolimnological studies. Here, we present the record of environmental changes over the last millennium that are recorded in the sediments of El Sol, a tropical, high-altitude, volcanic crater lake on the Nevado de Toluca, Central Mexico. Palaeolimnological reconstructions are based on subfossil Cladocera, diatoms, magnetic susceptibility and chemical analysis of the sediments. In general, Cladocera occurring in tropical regions, and especially at high altitude, have been studied very little. Our data indicate that in the sequence studied, the species diversity of subfossil Cladocera is very low. Only four species were recorded, and the assemblage is dominated by littoral species. Two Cladocera taxa, Alona manueli and Ilyocryptus, found at Lake El Sol are endemic. Cladocera, diatoms and the sediment chemistry show changes in Lake El Sol which are mostly related to climate. The most pronounced climatic signal was obtained for the early Little Ice Age (1350–1625 AD). This cold episode was expressed by a reduction in the frequency of zooplankton (individuals/cm2/yr) and diatoms (valves/g of dry sediment) and by changes in the organic carbon content in the sediment. Our results show that human activity was very limited throughout the study period. According to historical data the presence of humans at the lake shore was mostly occasional, usually for ceremonial and ritual purposes, and humans did not have an important influence on the lake ecosystem. Only one period was identified when human activity was important. This period corresponds to the introduction of fish into the lake at the beginning of the 20th century.
Źródło:
Geological Quarterly; 2017, 61, 1; 81--90
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Holocene evolution of the Pomeranian Bay environment, Southern Baltic Sea
Autorzy:
Kostecki, R.
Janczak-Kostecka, B.
Powiązania:
https://bibliotekanauki.pl/articles/48852.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
aerobic condition
anaerobic condition
Ancylus Lake
Baltic Sea
diatom assemblage
ecological group
geochemistry
Holocene
lacustrine sediment
marine diatom
marine environment
paleogeographic development
Pomeranian Bay
sediment core
shallow lake
Opis:
This article focuses on the diatom assemblages and geochemical composition of sediment cores retrieved from the Pomeranian Bay. We also discuss similarities and differences in the diatom assemblages and the palaeogeographic development of nearby regions. Our main objective was to determine the characteristics and rate of the Littorina transgression in the Pomeranian Bay area. Sediments were divided into units based on differences in the distribution of diatom ecological groups and in geochemical ratios, such as Mg/Ca, Na/K and Fe/Mn. This study identified lacustrine sediments deposited during the time of the Ancylus Lake. This lacustrine-period sedimentation took place in a shallow lake under aerobic conditions. The record of the onset of marine environment dates to 8900–8300 cal BP and corresponds to the Littorina transgression. After about 8300 cal BP, sedimentation took place in a deeper marine environment with higher biogenic production and anaerobic conditions. The abrupt appearance of marine diatom species and increased geochemical salinity indicators reflect the large impact of the Littorina transgression on the Pomeranian Bay environment.
Źródło:
Oceanologia; 2011, 53, (1-TI)
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Age and evolution of the Littorina Sea in the light of geochemical analysis and radiocarbon dating sediment of cores from the Arkona Basin and Mecklenburg Bay (SW Baltic Sea)
Autorzy:
Kostecki, R.
Powiązania:
https://bibliotekanauki.pl/articles/295074.pdf
Data publikacji:
2015
Wydawca:
Stowarzyszenie Geomorfologów Polskich
Tematy:
geochemistry
radiocarbon dating
Ancylus Lake
Littorina Sea
southwestern Baltic Sea
Opis:
Two sediment cores from the Mecklenburg Bay and Arkona Basin were analysed in terms of their geochemical composition and stratigraphy. The main stages of the Baltic Sea evolution – Baltic Ice Lake, Ancylus Lake, and Littorina Sea – were identified in both analysed cores. The most pronounced period was the transition between the Ancylus Lake and the Littorina Sea. The character of the initial stage of the Littorina Sea was clearly defined in the Mecklenburg Bay sediments and is marked by a stepwise increase in loss on ignition and contents of biogenic silica, calcium, magnesium, iron, and strontium. The record of the onset of the Littorina Sea in the Arkona Basin sediments is marked by an abrupt change of the geochemical parameters. The age of the initial Littorina Sea in the Mecklenburg Bay was estimated at about 8200 cal years BP and was probably older than the transgression within the Arkona Basin.
Źródło:
Landform Analysis; 2015, 29; 27-33
1429-799X
Pojawia się w:
Landform Analysis
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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