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Wyszukujesz frazę "anoxia" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Geochemical and ecological aspects of lower Frasnian pyrite-ammonoid level at Kostomłoty (Holy Cross Mountains, Poland)
Autorzy:
Racki, G.
Piechota, A.
Bond, D.
Wignall, P. B.
Powiązania:
https://bibliotekanauki.pl/articles/2060630.pdf
Data publikacji:
2004
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Holy Cross Mountains
Frasnian
pyritic fossils
geochemical proxies
anoxia
Timan Event
Opis:
The lower Frasnian (transitans Zone with Ancyrodella priamosica = MN 4 Zone) rhythmic basin succession of marly limestones and shales (upper Szydłówek Beds) at Kostomłoty, western Holy CrossMts., Central Poland, contains a record of the transgressive-hypoxic Timan Event in this drowned part of southern Laurussian shelf. The unique facies consists of organic-rich marly shales and a distinctive pyritic, goniatite level, 1.6mthick. The faunal assemblage is dominated by pyritized shells of diminutivemollusks with cephalopods (including goniatites Epitornoceras and Acanthoclymenia), buchioline bivalves (Glyptohallicardia) and styliolinids. This interval is marked by moderately low Th/U ratios and pyrite framboid size distributions suggestive of dysoxic rather than permanent euxinic conditions. The scarcity of infauna and bioturbation resulted in finely laminated sedimentary fabrics, as well as the low diversity of the presumed pioneer benthos (mostly brachiopods). In the topmost part of the Szydłówek Beds, distinguished by the Styliolina coquina interbedded between limestone-biodetrital layers, the above geochemical proxies and C-isotope positive shift indicate a tendency to somewhat increased bottom oxygen deficiency and higher carbon burial rate linked with a bloom of pelagic biota during high-productivity pulse. The geochemical and community changes are a complex regional record of the initial phase of a major perturbation in the earth-ocean system during a phase of intermittently rising sea level in the early to middle Frasnian, and associated with the highest positive C-isotope ratios of the Devonian.
Źródło:
Geological Quarterly; 2004, 48, 3; 267--282
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elemental and organic carbon proxies for redox conditions of the Oligocene formations in the Ropa Tectonic Window (Outer Carpathians, Poland) : palaeoenvironmental implications
Autorzy:
Wójcik-Tabol, P.
Powiązania:
https://bibliotekanauki.pl/articles/973585.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
organic matter
stable organic carbon isotope
trace metals
anoxia
Grybów Succession
Oligocene
Opis:
The Oligocene Grybów Succession is recognized as a counterpart of the anoxic Menilite Formation. Its comprehensive geochemical investigations are made in the key sections of the Ropa Tectonic Window (the Grybów Unit, Polish Outer Carpathians). The maceral assemblages, dominated by land-plant liptinite, vitrinite and intertinite, correspond to kerogen types II and III. A Tmax vs. HI diagram shows terrestrial kerogen type II with various additions of type III and algal kerogen type I. A variation in δ13Corg. (from –25.21 to –27.38‰) may have resulted from variations in the composition of organic matter (the content of terrestrial vs. marine organic matter), controlled by depositional setting (turbidite vs. hemipelagic). The highest TOC contents are associated with an enhanced influx of land-derived organic matter. The redox-sensitive trace elements positively correlate with TOC and TS contents. Redox conditions varied between oxic and anoxic, as was concluded from TOC-TS, V/(V+Ni) and U/Th. The turbidity currents might have ventilated the bottom waters, especially more efficiently in the proximal zone of turbidite sedimentation. Moreover, oxygenated bottom waters may have also affected the concentration of trace metals, owing to migration of the redox interface downward within the sediments.
Źródło:
Annales Societatis Geologorum Poloniae; 2017, 87, 1; 41-53
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First record of rare fish snake blenny Lumpenus lampretaeformis (Walbaum 1792) in the Puck Bay
Pierwsze odnotowanie rzadkiego gatunku ryby taśmiaka długiego Lumpenus lampretaeformis (Walbaum 1792) w wodach Zatoki Puckiej
Autorzy:
Pieckiel, P.
Wawrzyniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/972878.pdf
Data publikacji:
2016
Wydawca:
Instytut Morski w Gdańsku
Tematy:
snake blenny
Lumpenus
Puck Bay
relict
anoxia
taśmiak długi
Zatoka Pucka
relikt
niedobory tlenowe
Opis:
Snake blenny was noted for the first time in the Puck Bay [see Fig.1] on depth 42.1 m. This part of the Bay is connected with Gdańsk, deep with the maximum depth of 118 m. Snake blenny is probably a post glacial relict fish species in the Baltic. It prefers comparatively deep waters between 30 m to 120 m, as those water depths probably holds the suitable habitat for the fish for spawning and feeding life. However, considering snake blenny’s low tolerance for oxygen deficiency, which may occur in deepest parts of the Gulf of Gdansk, this species may be endangered in this area.
Taśmiak długi Lumpenus lampretaeformis (Walbaum 1792) został odnotowany po raz pierwszy w wodach Zatoki Puckiej na głębokości 42,1 m (rys 1.) w bezpośrednim sąsiedztwie Głębi Gdańskiej gdzie maksymalna głębokość dochodzi do 118 m. W Bałtyku ryba ta jest prawdopodobnie reliktem pochodzenia polodowcowego. Siedliskiem taśmiaka długiego, zarówno dla celów rozrodczych jak i żerowiskowych, w Bałtyku są wody w zakresie głębokości od 30 m do 120 m. Biorąc pod uwagę wrażliwość tego gatunku na niedobory tlenowe, które występują w Bałtyku w szczególności w najgłębszych partiach wód włączając tu Głębię Gdańską, jego siedliska mogą być zagrożone.
Źródło:
Biuletyn Instytutu Morskiego w Gdańsku; 2016, 31, 1; 7-10
1230-7424
2450-5536
Pojawia się w:
Biuletyn Instytutu Morskiego w Gdańsku
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
PO4 release at the sediment surface under anoxic conditions: a contribution to the eutrophication of the Baltic Sea?
Autorzy:
Schneider, B.
Powiązania:
https://bibliotekanauki.pl/articles/49162.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
anoxia
biogeochemical condition
carbon dioxide
deep water
dissolved inorganic nitrogen
eutrophication
hydrogen sulphide
mineralization
nutrient concentration
oxygen
phosphate
sediment
Opis:
The vertical profiles of phosphate, total CO2 and oxygen/hydrogen sulphide were determined in the deep water of the Gotland Sea during March 2003 to July 2006 with a temporal resolution of 2–3 months. This time span included the shift from anoxic to oxic conditions resulting from a water renewal event, as well as the transition back to anoxic waters during the subsequent two-year stagnation period. The data from depths below 150 m were used to identify and quantify phosphate release and removal processes. The relationship between the total CO2 generated by mineralization (CT1 min) and the PO4 concentrations indicated that the initial decrease in the phosphate concentrations after the inflow of oxygen-rich water was mainly a dilution effect. Only about one third of the PO4 removal was a consequence of the precipitation of insoluble iron-3-hydroxo-phosphates (Fe-P), which occurred slowly at the sediment surface under oxic conditions. From the CT1 min/PO4 ratios it was also concluded that the formation of Fe-P was reversed during the later phase of the stagnation, when the redoxcline approached a depth of 150 m. A phosphate mass balance was performed for four deep water sub-layers in order to quantify the dissolution of Fe-P during the stagnation period and thus to estimate the amount of Fe-P deposited during the last inflow of oxygen-rich water. A value of about 50 mmol-P m−2 was found, which refers to the specific biogeochemical conditions during the change from anoxic to oxic conditions that preceded the stagnation period.
Źródło:
Oceanologia; 2011, 53, (1-TI)
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Framboidy pirytowe jako wskaźniki paleośrodowiska
Pyrite framboids as paleoenvironmental indicators
Autorzy:
Zatoń, M.
Rakociński, M.
Marynowski, L.
Powiązania:
https://bibliotekanauki.pl/articles/2074589.pdf
Data publikacji:
2008
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
framboidy pirytowe
redoks
warunki środowiskowe oksyczne
warunki środowiskowe dysoksyczne
warunki środowiskowe euksyniczne
jura
dewon
Polska
pyrite framboids
redox
euxinia
anoxia
dysoxia
Jurassic
Devonian
Polska
Opis:
The problemof application of pyrite framboids in reconstructions of the redox conditions is presented. The characteristics of pyrite framboids, their origin and principles of application in paleoenvironmental interpretations are given. The pyrite framboid diameter distribution as indicators of redox conditions was presented on the examples of the Middle Jurassic (Upper Bajocian-Lower Bathonian) ore-bearing clays of the Polish Jura, and Upper Devonian (Middle and Upper Famennian) dark grey and black shales from Kowala (Holy Cross Mountains). It has been shown, that during the sedimentation of the ore-bearing clays, the pyrite framboids formed in the sediment, below the oxic water column; however, some episodic oscillation around the dysoxic conditions cannot be entirely excluded. During the sedimentation of the Middle Famennian dark grey shales, the redox conditions at the sea-floor oscillated around dysoxia. In both examples, the framboids are characterized by wide range of their diameters and the presence of large, >10 "my"m, framboids. On the contrary, the Upper Famennian black shales, representing the Hangenberg event, were deposited below the euxinic conditions in the water column. It is indicated by a high frequency of small-size framboids, far below 6 "my"m in diameter, and the lack of the large ones. The overlying shales, on the other hand, show the transition to more oxic conditions. The redox conditions interpreted above are in agreement with the independent biomarker analyses and paleontological observations.
Źródło:
Przegląd Geologiczny; 2008, 56, 2; 158-164
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geochemical and stable isotope patterns of calcite cementation in the Upper Cretaceous Chalk, UK: Direct evidence from calcite-filled vugs in brachiopods
Autorzy:
Hu, X.
Jeans, C.
Dickson, T.
Powiązania:
https://bibliotekanauki.pl/articles/139259.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cement kalcytowy
diageneza
historia
izotopy stabilne
kreda
pierwiastki śladowe
wpływ drobnoustrojów
anoxia
calcite cement
chalk
diagenesis
history
Microbial influence
oxia
stable isotopes
suboxia
trace elements
Opis:
The history of research into the cementation of the Upper Cretaceous Chalk of the UK is reviewed. Calcite-filled vugs within the shell cavities of terebratulid brachiopods from the Cenomanian Chalk of eastern england have been investigated by cathodoluminesence imaging, staining, electron microprobe and stable isotope analysis. This has provided the first detailed analysis of the geochemistry of the Chalk.s cement. two cement series, suboxic and anoxic, are recognized. Both start with a Mg-rich calcite with positive [delta^13]C values considered to have been precipitated under oxic conditions influenced by aerobic ammonification. The suboxic series is characterized by positive [delta^13]C values that became increasingly so as cementation progressed, reaching values of 3.5[per mil]. Manganese is the dominant trace element in the earlier cement, iron in the later cement. Mn-and Fe-reducing microbes influenced cement precipitation and the trace element and [delta^13]C patterns. The anoxic series is characterized by [delta^13]C values that became increasingly negative as cementation progressed, reaching values of .6.5[per mil]. Trace elements are dominated by iron and manganese. Sulphate-reducing microbes influenced cement precipitation and the trace element and [delta^13]C patterns. Both cement series are related closely to lithofacies and early lithification pre-dating the regional hardening of the Chalk. The suboxic series occurs in chalk which was continuously deposited and contained hematite pigment and limited organic matter. The anoxic series was associated with slow to nil deposition and hardground development inc halks that originally contained hematite pigment but no longer do so, and an enhanced supply of organic matter.
Źródło:
Acta Geologica Polonica; 2012, 62, 2; 143-172
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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