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Wyszukujesz frazę "redox" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
Geochemistry of Middle Jurassic mudstones (Kraków-Częstochowa area, southern Poland): interpretation of the depositional redox conditions
Autorzy:
Szczepanik, P.
Witkowska, M.
Sawłowicz, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2059479.pdf
Data publikacji:
2007
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Middle Jurassic
Częstochowa Clay Formation
palaeoenvironment
geochemical parameters
redox conditions
Opis:
Middle Bathonian iron-bearing dark grey mdstones and claystones from the Kraków-Czestochowa Upland (southern Poland) were subjected to geochemical and mineralogical study in order to evaluate palaeo-redox conditions of their deposition and diagenesis. They are mainly composed of kaolinite, with smaller amounts of other clay minerals and detrital quartz. Organic matter is composed of type III and/or IV kerogen and its d13C is between -23 and -24‰, suggesting a mainly terrigenous source, with a possible admixture of marine input. Most geochemical parameters: (total organic carbon) TOC/S, U/Th, Ni/Co, V/Cr, (Cu+Mo)/Zn ratios, authigenic uranium content, and Fe-TOC-S relationship, indicate deposition under oxygenated bottom water conditions. By contrast, DOP (degree of pyritization) and V/V+Ni indices suggest a dysoxic environment. However, DOP probably reflects redox conditions in the sediment during diagenesis rather than in the over laying water column. The composition of the organic matter and the domination of pyrite euhedra over framboids indicates that the V/V+Ni ratio may not be reliable for determination of redox conditions in the rocks studied. There is no significant difference between the geochemical indices of host rocks with nodules and those with out them.
Źródło:
Geological Quarterly; 2007, 51, 1; 57-66
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geochemical and faunal proxies in the Westphalian A (Langsettian) marine horizon of the Lublin Coal Basin
Autorzy:
Krzeszowska, E.
Powiązania:
https://bibliotekanauki.pl/articles/2060565.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
inorganic geochemistry
palaeo-redox conditions
Dunbarella horizon
Lublin Coal Basin
Opis:
The uppermost Westphalian marine horizon (Dunbarella horizon) is especially important for correlation of Carboniferous deposits in the Lublin Coal Basin and in other basins of the Northwest European Carboniferous Basin. The Dunbarella horizon is characterized by cyclic sedimentation and consequent faunal spectrum variability, typical for Westphalian marine horizons of northwestern Europe. Palaeontological study of the Dunbarella horizon showed the presence of macrofauna representing different palaeoenvironments, from marine to brackish (non-marine) and freshwater conditions. The vertical sea level fluctuations and changes in seawater salinity resulting in palaeontological record changes do not link with geochemical proxies. TOC, redox-sensitive trace element concentrations, and V/Cr, Ni/Co and V/(V + Ni) ratios generally suggest that the Dunbarella horizon sediments were deposited under predominantly oxic conditions (with local exceptions during the initial phase of the Dunbarella ingression; Kopina 1 borehole).
Źródło:
Geological Quarterly; 2017, 61, 4; 751--764
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trace element variations as a proxy for reconstruction of palaeoenvironmental changes during the Late Aeronian faunal and carbon isotope perturbations: new data from the peri-Gondwanan region
Autorzy:
Pašava, J.
Frýda, J.
Štorch, P.
Powiązania:
https://bibliotekanauki.pl/articles/2060353.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Aeronian
graptolite mass extinction
redox-sensitive trace elements
Barrandian area
Bohemian Massif
Opis:
Trace element variations in the Upper Aeronian (Llandovery, Lower Silurian), deep-water, black shale succession of the Barrandian area (Perunica) were studied across an interval associated with a graptolite mass extinction and global, positive carbon isotope anomaly. The main aim of the paper is to test whether distinct changes in graptolite diversity during Late Aeronian were linked with changes in deep sea water oxygenation. Using multiple geochemical proxies we documented high-frequency changes in oxygenation of sea water from sediments of the convolutus to linnaei (guerichi) biozones. Detailed comparison of graptolite diversity with those high-frequency oxygenation changes suggests that the long-term and step-wise Late Aeronian graptolite crisis was not significantly influenced by changes in oxygen level and thus it probably resulted by another causes. The collapse of global carbon cycle during the Late Aeronian probably only temporarily increased extinction rate of the long-term graptolite crisis and considerably decreased evenness of the uppermost Aeronian graptolite communities. The Aeronian graptolite mass extinction was thus primarily driven by other biotic and/or abiotic causes
Źródło:
Geological Quarterly; 2017, 61, 1; 91--98
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania potencjału redoks na przykładzie sudeckich wód leczniczych
Research of redox potential on the example of curativewaters in the Sudetes Mts., Poland
Autorzy:
Dobrzyński, D.
Powiązania:
https://bibliotekanauki.pl/articles/2074741.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
chemizm wód podziemnych
ptencjał redoks
wody lecznicze
Sudety
groundwater chemistry
redox potential
curative water
Sudetes
Opis:
In Poland, the redox potential (EH) is seldomly measured in groundwater. Since the year 2006 determination of redox potential is required for documenting properties of curative mineral waters. Investigations of redox conditions in groundwater need both proper measurement and interpretation. In the paper, crucial questions of: 1) redox equilibrium in groundwater, 2) field measurement, 3) correction methods, and 4) EH interpretation are presented. Some aspects of applying the redox potential for interpreting groundwater chemistry and using geochemical modelling are illustrated by hydrochemical data of curative waters from spas in the Sudetes Mts., SW Poland. Main reasons of the common redox non-equilibrium found in groundwater are co-existence of numerous aqueous redox pairs and usually non-equilibrium in particular redox pairs. Redox determinations have to be done in the field, and require extreme cleanness and precision, e.g., measuring without contact with the atmospheric air. Field measurements must be corrected to the standard hydrogen electrode, considering: type of reference electrode, concentration of electrode filling solution, type of standard redox solution, and water temperature. The redox potential has been measured in water at first from all the Sudetic spas, totally in 33 water intakes. In curative waters from the Sudetes corrected EH ranges between –159 mV and +343 mV. Usually, thermal waters show lower EH values than cold, CO2-rich waters. The lowest redox potential was found in the hottest thermal waters, i.e., in water from Zdzisław intake (in Lądek Zdrój) and C-2 intake (in Cieplice Śląskie Zdrój). Generally, the higher the pH, the lower the EH in groundwater. Methods of geochemical modelling, which are often and often applied in groundwater research, also require the EH determination. Information about EH are used in the calculation of speciation models of water, and affect the results of whole geochemical modelling as well as evaluations of the saturation state. The speciation-solubility modelling for the Sudetic curative waters, presented in the paper, shows that the proper correction of field EH measurement determines the quality of calculations. Improperly corrected EH values might lead to species activity errors, even up to several order of magnitudes, and erroneous interpretation of the mineral phases stability in the hydrogeochemical system.
Źródło:
Przegląd Geologiczny; 2010, 58, 1; 46-53
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fenomen kambryjskich łupków z Burgess w Górach Skalistych (Kanada) : przegląd fauny, środowiska sedymentacji i zjawisk tafonomicznych
The Cambrian Burgess Shale phenomenon of the Rocky Mountains (Canada) : an overview of the fauna, sedimentary and taphonomic conditions
Autorzy:
Śliwiński, M. G.
Żylińska, A.
Powiązania:
https://bibliotekanauki.pl/articles/2075033.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Cambrian
Burgess Shale
Rocky Mountains
Lagerstätten
redox
kambr
łupki z Burgess
Góry Skaliste
natlenienie wód
Opis:
The Burgess Shale of the Canadian Rocky Mts is one of the most well-known occurrences of Cambrian strata exhibiting exceptional preservation of a soft-bodied fauna. While Lagerstätten of the Burgess Shale-type fauna have been recognized in almost all parts of the world and in all Cambrian series, the circumstances and mechanisms allowing for such a unique mode of preservation have remained enigmatic. Of particular debate has been the reconstruction of prevailing redox conditions. This brief contribution overviews the fauna and recent advances towards understanding the sedimentary and taphonomic conditions prevailing during deposition.
Źródło:
Przegląd Geologiczny; 2013, 61, 12; 746--754
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena dystrybucji arsenu w wybranych wodach leczniczych Sudetów na podstawie filtracji membranowej i modelowania specjacyjnego
Evaluation of arsenic distribution in selected curative mineral waters from the Sudetes Mts. based on membrane filtration and speciation modelling
Autorzy:
Dobrzyński, D.
Stępień, M.
Powiązania:
https://bibliotekanauki.pl/articles/2063210.pdf
Data publikacji:
2009
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
arsen
wody podziemne
wody lecznicze
filtracja membranowa
modelowanie specjacyjne
potencjał redoks
arsenic
groundwaters
curative water
membrane filtration
speciation modelling
redox potential
Opis:
Filtracja membranowa wybranych sudeckich wód leczniczych przez filtry o różnych rozmiarach porów (od 0,1 do 180 micro/m) pozwoliła zilustrować dystrybucję arsenu w wodzie wywołaną obecnością faz (roztwór, koloidy, zawiesiny) o różnych rozmiarach cząstek. Modelowanie specjacyjne wskazuje, że w większości wód specjacje arsenu (V) przeważają nad specjacjami arsenu (III). Badane wody lecznicze są zwykle w widocznej równowadze redoks dla pary As(V) / As(III).
Membrane filtration of selected curative mineral waters (Sudetes Mts., S W Poland) by filters of various (from 0.1 to 180 micro/m) pore size allowed illustrating distribution of arsenic in water which is related to size of forms (solutes, colloids, particulate matter) occurred. Speciation geochemical modelling showed that in most of curative waters, species of As(~ prevails over As(III) species. Studied curative waters are usually in apparent redox equilibrium in terms of As(V) / As(III) redox species pair.
Źródło:
Biuletyn Państwowego Instytutu Geologicznego; 2009, 436, z. 9/1; 95-101
0867-6143
Pojawia się w:
Biuletyn Państwowego Instytutu Geologicznego
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
    Wyświetlanie 1-7 z 7

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