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Wyszukujesz frazę "izotop węgla" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Sedimentary development and isotope analysis of deposits at the Cretaceous/Palaeogene transition in the Paraíba Basin, NE Brazil
Autorzy:
Neumann, Virgínio Henrique
Barbosa, José Antônio
Nascimento-Silva, Valberlândia Maria
Sial, Alcides Nobrega
Filho, Mario
Powiązania:
https://bibliotekanauki.pl/articles/94597.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
NE Brazil
Cretaceous-Paleogene boundary
carbon isotopes
oxygen isotopes
Brazylia
izotop węgla
izotop tlenu
Opis:
New data are presented for three formations (Itamaracá, Gramame and Maria Farinha) and two boundaries (Campanian/Maastrichtian and Maastrichtian/Danian) in the Olinda Sub-basin of the Paraíba Basin. Currently accepted facies models, sequence stratigraphy characterizations, and stable-isotope data of carbon and oxygen are reviewed. The carbonate cement of the Itamaracá Formation sandstones shows carbon- and oxygen-isotope ratios consistent with a shallow-marine depositional environment: δ18O ranges from -0.8 to -2.7‰ PDB, and δ13C ranges from +1 to +2‰ PDB. Within the Itamaracá Formation, a maximum flooding surface at the Campanian/Maastrichtian transition has been identified. During the Maastrichtian, a Highstand System Tract was deposited, which shows an increase in temperature and marine bioproductivity as recorded by stable-isotope values (δ18O from -3 to -5‰ PDB, and δ13C values of -1.2, -0.3, 0.1 and +2.3‰ PDB). Just below the K/Pg boundary, the O-isotope signal indicates three warming phases, alternating with four cooling phases.
Źródło:
Geologos; 2009, 15, 2; 103-113
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metodyka analiz izotopowych rozpuszczonego węgla nieorganicznego (DIC) i ich zastosowania w badaniach hydrogeologicznych i środowiskowych
Methodology and application of stable isotope analysis of dissolved inorganic carbon (DIC) in hydrogeology and environmental studies
Autorzy:
Szynkiewicz, A.
Drzewicki, W.
Jędrysek, M. O.
Powiązania:
https://bibliotekanauki.pl/articles/2074490.pdf
Data publikacji:
2006
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
rozpuszczony węgiel nieorganiczny (DIC)
izotop węgla
dissolved inorganic carbon
carbon isotopes
Opis:
The analysis of carbon isotope composition of dissolved inorganic carbon (DIC) is widely applied in hydrogeology and environmental studies. The method of analysis is simple and based on conversion of all DIC species to gaseus CO2 under acidic conditions. However, the analytical procedure may involve significant carbon isotope fractionation. Our experimental analysis showed that increasing the time of CO2 extraction influences the increase of ä13C(DIC) value as a result of re-dissolution of CO2 in the water expanded on the vacuum line or/and carbon isotope exchange between the extracted CO2 and the atmospheric CO2. The long time of sample storage yields an increase of ä13C(DIC) value and decrease of DIC concentration. The analytical precision up to š 0,1‰ may be achieved in the case of waters being analyzed few days after sampling. DIC concentration was evaluated according to height of peak 44 in the mass spectrum. The analytical precision of this method was š 2 mgCO2 per dm3. This method is very useful because the measurements of the height of peak 44 and carbon isotope composition of DIC can be performed simultaneously. However, this method is reliable for waters containing more than 4 mg CO2 per dm3
Źródło:
Przegląd Geologiczny; 2006, 54, 9; 797-806
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geochemical and isotopic analyses of PM10 in Lower Silesia - preeliminary data
Autorzy:
Zwolińska, E.
Ciężka, M.
Powiązania:
https://bibliotekanauki.pl/articles/100782.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Śląski. Wydział Nauk o Ziemi
Tematy:
PM10
pył
analiza
izotop węgla
Dolny Śląsk
zanieczyszczenia atmosferyczne
PM10 dust
carbon isotopic analyses
Lower Silesia
atmospheric pollutants
Opis:
The main aim of the study was to determine the origin of particulate air pollution in Lower Silesia. Samples of PM10 dust were collected on quartz filters Whatman QM-A by employees of Voivodship Inspectorate for Environmental Protection (VIEP) in Wroclaw in 2011. As a pilot researches in Lower Silesia were selected two monitoring points of VIEP: (i) Osieczow and (ii) Zgorzelec. Air sampling point in Osieczow is a point of regional background and it is an excellent reference base for the analyses of PM10 in Lower Silesia. The aim of monitoring in this point is to assess the exposure of ecosystems to air pollution. Sampling point in Zgorzelec reflects the urban background and the measurements will be compared, in the future, to the results of the sampling points investigated the impact of industry and local transport on air quality in the whole Lower Silesia. For further geochemical and isotopic analyses were selected 25 samples from each sampling point, average every two weeks measurement. The concentration of PM10 dust for Osieczow ranged from 7 μg·m-3 (11.10.2011r.) to 89 μg·m-3 (4.03.2011r.) with an average of 24 μg·m-3 and for Zgorzelec between 10 μg·m-3 (11.10.2011r.) and 85 μg·m-3 (9.11.2011r.) with an average of 26 μg·m-3. The mean percentage contribution of carbon in PM10 samples from Osieczow was 47%, while in Zgorzelec 42%. The obtained values of δ13C (PM10) in Osieczow varied from -31.1‰ (5.02.2011r.) to -25.5‰ (26.10.2011r.) with an average of -27.6‰, whereas in Zgorzelec between -28.6‰ (15.07.2011r.) and -25.2‰ (6.01.2011r.) with an average of -26.8‰. At the current stage of research is clearly discernible the different carbon isotope record in the material dust (qualitative information), despite the identical range of concentrations of PM10 in both analysed points (quantitative information). This confirms the appropriateness of the choice both research method and monitoring points.
Źródło:
Contemporary Trends in Geoscience; 2013, 2, 1; 101-105
2299-8179
Pojawia się w:
Contemporary Trends in Geoscience
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in paleo-circulation and the distribution of ammonite faunas at the Coniacian–Santonian transition in central Poland and western Ukraine
Autorzy:
Remin, Z.
Gruszczyński, M.
Marshall, J. D.
Powiązania:
https://bibliotekanauki.pl/articles/139412.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Coniacian–Santonian transition
paleogeography
paleo-circulation
ammonites
carbon stable isotopes
oxygen stable isotopes
paleogeografia
amonity
izotopy węgla
izotop tlenu
Opis:
Ammonite distribution patterns and carbon and oxygen stable isotopes from the Lipnik-Kije (Poland) and Dubovcy (Ukraine) sections allow us to propose a model of sea water paleo-circulation in central Europe for the Coniacian-Santonian interval. The tectonic evolution of the south-eastern part of Poland, and expansion of the Krukienic Island areas, appears to have been one of the most important factors affecting paleotemperatures and the distribution of ammonite faunas in the shallow, epicontinental sea in this part of Europe. In the Lipnik-Kije section, low-latitude Tethyan ammonites, especially of the genera Nowakites, Parapuzosia and Saghalinites, are mixed with the cold water loving ammonite genus Kitchinites in the Lower Santonian. In the Dubovcy section (western Ukraine), Tethyan ammonites disappear abruptly in the earliest Santonian, giving place to temperate ammonites of the Kitchinites group in the early Early Santonian and to Boreal belemnites of the genus Gonioteuthis in the Middle and Late Santonian. Despite evidence for the effects of diagenesis in both sections, bulk-rock δ18O records from the limestones support higher seawater paleotemperatures in the Polish sea and cooler conditions in the western Ukraine. The proposed paleo-circulation model and paleotemperature distribution across Europe is supported independently by changes in faunal and nannoflora evidence (ammonites, foraminifera and nannoplankton), and rather unexpectedly with the bulk δ18O data. These data allow the recognition of the end-Coniacian–Early Santonian cooling event, resulting from cold currents flowing from the north, which is traceable, with different magnitude, in several European sections. Facies changes in both sections are related to the input of terrigenous material, and linked to Subhercynian tectonic movements which affected the eastern (Ukrainian) and central (Holy Cross) segment of the Mid Polish Trough at different times. Uplift and sediment input moved westwards through time. Clastic input is detectable at the Coniacian–Santonian boundary in the Ukrainian segment. Similar facies changes reached the Holy Cross segment in Poland distinctly later, somewhen in the Middle Santonian. It is likely that tectonics together with paleo-circulation changes markedly restricted or even cut-off the western Ukraine area from Tethyan ocean influences in the Early Santonian.
Źródło:
Acta Geologica Polonica; 2016, 66, 1; 107-124
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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