Temat: δ18O - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Note on the stable isotope values of vein calcite in the El-Seboah peralkaline granite (SW Egypt)
Autorzy:: Hassan, Kamaleldin M.
Powiązania:: https://bibliotekanauki.pl/articles/2086490.pdf
Data publikacji:: 2011
Wydawca:: Polskie Towarzystwo Mineralogiczne
Tematy:: δ13C
δ18O
carbonate-hosting veins
peralkaline granite
Egypt
Opis:: Stable isotope data for carbon (δ13C) and oxygen (δ18O) are used to constrain the environments of calcite formation in two veins in the El-Seboah peralkaline granite in south-western Egypt. Vein I with calcitemagnetite-goethite-hematite-quartz, and vein II with calcite-magnetite-goethite-kaolinite-hematite-quartz are texturally distinct. The calcite of each vein has characteristic δ13C- and δ18O-values: + 0.32 and -7.28‰ for vein I and + 1.16 and - 1.21‰ for vein II, respectively. The observed differences between the δ13C values of the two veins indicate that they represent two separate systems of primary dissolved inorganic carbon formed at or near equilibrium with atmospheric CO2. The δ18O values, on the other hand, indicate calcite deposition from meteoric waters which were fresh for vein I and brackish for vein II.
Źródło:: Mineralogia; 2011, 42, 2/3; 113--120
1899-8291
1899-8526
Pojawia się w:: Mineralogia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Isotopic studies of nitrates – a short review
Autorzy:: Gebus, Beata
Hałas, Stanisław
Powiązania:: https://bibliotekanauki.pl/articles/763365.pdf
Data publikacji:: 2015
Wydawca:: Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:: nitrogen
nitrate
isotopic analysis
δ15N value
δ18O value
Opis:: Nitrogen is an essential element for life. One of its available forms are nitrates - the compounds playing a key role in the biogeochemical N cycle. However, excessive amounts of nitrates may be harmful to organisms and the environment, therefore in recent years the emphasis is on continuous monitoring of quality of consumed water. Nitrates from different sources have wide, but different ranges δ15N and δ18O. Also researchers observed typical changes in both delta values induced by biological processes and in the case of mixing water with anthropogenic nitrates. This is a reason why the isotopic analysis are often used to identify the source of contamination in a reservoir or to quantitatively describe the processes occurring in an ecosystem.In this review article, we present a model of the global nitrogen cycle, along with the latest data on the disturbances caused by human activity. We describe the processes occurring in the N cycle and biogeochemical mechanisms, which modify the nitrogen isotopic composition in their compounds. We also present a short description of analytical techniques utilized for studying isotopic compositions of nitrates. In addition, we discussed the methods for extraction and preparation of nitrates from freshwater and ocean water, by determining the δ15N, δ18O and δ17O (or Δ17O) values. The final part is a description of applications of developed techniques for environmental research.
Źródło:: Annales Universitatis Mariae Curie-Skłodowska, sectio AAA – Physica; 2015, 70
0137-6861
Pojawia się w:: Annales Universitatis Mariae Curie-Skłodowska, sectio AAA – Physica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Note on the stable isotope values of vein calcite in the El-Seboah peralkaline granite (SW Egypt)
Autorzy:: Hassan, K. M.
Powiązania:: https://bibliotekanauki.pl/articles/2086543.pdf
Data publikacji:: 2011
Wydawca:: Polskie Towarzystwo Mineralogiczne
Tematy:: δ13C
δ18O
carbonate-hosting veins
peralkaline granite
Egypt
Opis:: Stable isotope data for carbon (δ13C) and oxygen (δ18O) are used to constrain the environments of calcite formation in two veins in the El-Seboah peralkaline granite in south-western Egypt. Vein I with calcitemagnetite-goethite-hematite-quartz, and vein II with calcite-magnetite-goethite-kaolinite-hematite-quartz are texturally distinct. The calcite of each vein has characteristic δ13C- and δ18O-values: + 0.32 and -7.28‰ for vein I and + 1.16 and - 1.21‰ for vein II, respectively. The observed differences between the δ13C values of the two veins indicate that they represent two separate systems of primary dissolved inorganic carbon formed at or near equilibrium with atmospheric CO2. The δ18O values, on the other hand, indicate calcite deposition from meteoric waters which were fresh for vein I and brackish for vein II.
Źródło:: Mineralogia; 2011, 42, 2/3; 113--120
1899-8291
1899-8526
Pojawia się w:: Mineralogia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Oxygen isotope analysis of shark teeth phosphates from Bartonian (Eocene) deposits in Mangyshlak peninsula, Kazakhstan
Autorzy:: Pelc, Andrzej
Hałas, Stanisław
Niedźwiedzki, Robert
Powiązania:: https://bibliotekanauki.pl/articles/2086485.pdf
Data publikacji:: 2011
Wydawca:: Polskie Towarzystwo Mineralogiczne
Tematy:: Bartonian
carbonate
Mangyshlak peninsula
phosphate
shark teeth
δ18O
δ13C
Opis:: We report the results of high-precision (±0.05‰) oxygen isotope analysis of phosphates in 6 teeth of fossil sharks from the Mangyshlak peninsula. This precision was achieved by the offline preparation of CO2 which was then analyzed on a dual-inlet and triple-collector IRMS. The teeth samples were separated from Middle- and Late Bartonian sediments cropping out in two locations, Usak and Kuilus. Seawater temperatures calculated from the δ18O data vary from 23–41oC. However, these temperatures are probably overestimated due to freshwater inflow. The data point at higher temperature in the Late Bartonian than in the Middle Bartonian and suggest differences in the depth habitats of the shark species studied.
Źródło:: Mineralogia; 2011, 42, 1; 53--61
1899-8291
1899-8526
Pojawia się w:: Mineralogia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Oxygen isotope analysis of shark teeth phosphates from Bartonian (Eocene) deposits in Mangyshlak peninsula, Kazakhstan
Autorzy:: Pelc, A.
Hałas, S.
Niedźwiedzki, R.
Powiązania:: https://bibliotekanauki.pl/articles/2086536.pdf
Data publikacji:: 2011
Wydawca:: Polskie Towarzystwo Mineralogiczne
Tematy:: Bartonian
carbonate
Mangyshlak peninsula
phosphate
shark teeth
δ18O
δ13C
Opis:: We report the results of high-precision (±0.05‰) oxygen isotope analysis of phosphates in 6 teeth of fossil sharks from the Mangyshlak peninsula. This precision was achieved by the offline preparation of CO2 which was then analyzed on a dual-inlet and triple-collector IRMS. The teeth samples were separated from Middle- and Late Bartonian sediments cropping out in two locations, Usak and Kuilus. Seawater temperatures calculated from the δ18O data vary from 23–41oC. However, these temperatures are probably overestimated due to freshwater inflow. The data point at higher temperature in the Late Bartonian than in the Middle Bartonian and suggest differences in the depth habitats of the shark species studied.
Źródło:: Mineralogia; 2011, 42, 1; 53--61
1899-8291
1899-8526
Pojawia się w:: Mineralogia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Geological and geochemical implications of the genesis of the Qolqoleh orogenic gold mineralisation, Kurdistan Province (Iran)
Autorzy:: Taghipour, B.
Ahmadnejad, F.
Powiązania:: https://bibliotekanauki.pl/articles/94346.pdf
Data publikacji:: 2015
Wydawca:: Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:: fluid inclusion
δ18O and δD isotopes
rare earth and trace element mobility
Sanandaj-Sirjan Zone
Iran
inkluzja fluidalna
izotopy
δ18O
δD
pierwiastki ziem rzadkich
pierwiastki śladowe
Opis:: The Qolqoleh gold deposit is located in the northwestern part of the Sanandaj–Sirjan Zone (SSZ), within the NE–SW trending Qolqoleh shear zone. Oligocene granitoids, Cretaceous meta-limestones, schists and metavolcanics are the main lithological units. Chondrite-normalised REE patterns of the ore-hosting metavolcanics indicate REE enrichment relative to hanging wall (chlorite-sericite schist) and footwall (meta-limestone) rocks. The pattern also reflects an enrichment in LREE relative to HREE. It seems that the LREE enrichment is related to the circulation of SO42- and CO2-bearing fluids and regional metamorphism in the Qolqoleh shear zone. Both positive and negative Eu anomalies are observed in shear-zone metavolcanics. These anomalies are related to the degree of plagioclase alteration during gold mineralisation and hydrothermal alteration. In progressing from a metavolcanic protomylonite to an ultramylonite, significant changes occurred in the major/trace element and REE concentration. Utilising an Al-Fe-Ti isocon for the ore-hosting metavolcanics shows that Sc, Y, K, U, P, and M-HREE (except Eu) are relatively unchanged; S, As, Ag, Au, Ca, LOI, Rb and LREE are enriched, and Sr, Ba, Eu, Cr, Co and Ni decrease with an increasing degree of deformation. Based on geochemical features and comparison with other well-known shear zones in the world, the study area is best classified as an Isovolume-Gain (IVG) type shear zone and orogenic type gold mineralisation. Based on the number of phases observed at room temperature and their microthermometric behaviour, three fluid inclusion types have been recognised in quartz-sulphide and quartz-calcite veins: Type I monophase aqueous inclusions, Type II two-phase liquid-vapour (L-V) inclusions which are subdivided into two groups based on the homogenisation temperature (Th): a) L-V inclusions with Th from 205 to 255°C and melting temperature of last ice (Tm) from –3 to –9°C. b) L-V inclusions with higher Th from 335 to 385°C and Tm from –11 to –16°C. Type III three-phase carbonic-liquid inclusions (liquid water-liquid CO2-vapour CO2) with Th of 345–385°C. The mean values of the density of ore-forming fluids, pressure and depth of mineralisation have been calculated to be 0.79–0.96 gr/cm3, 2 kbar and 7 km, respectively. The δ18Owater and δD values of the gold-bearing quartz-sulphide veins vary from 7.2‰ to 8‰ and –40.24‰ to –35.28‰, respectively, which are indicative of an isotopically heavy crustal fluid and likely little involvement of meteoric fluid. The δ18Owater values of the quartz-calcite veins have a range of –5.31‰ to –3.35‰, and the δD values of –95.65‰ to –75.31‰, which are clearly lower than those of early-stage quartz-sulphide-gold veins, and are close to the meteoric water line. Based on comparisons of the D–O isotopic systematics, the Qolqoleh ore-mineralising fluids originated from metamorphic devolatilisation of Cretaceous volcano-sedimentary piles. Devolatilisation of these units occurred either synchronously with, or postdates, the development of penetrative (ductile) structures such as shear zones and during overprinting brittle deformation.
Źródło:: Geologos; 2015, 21, 1; 31-57
1426-8981
2080-6574
Pojawia się w:: Geologos
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Zmiany klimatu półkuli północnej (na podstawie wahań promieniowania słonecznego i izotopu tlenu δ18O)
Changes of climate of the northern hemisphere (on the basis of fl uctuations of the solar radiation and oxygen isotope δ18O)
Autorzy:: Boryczka, J.
Stopa-Boryczka, M.
Unton-Pyziolek, A.
Gieszcz, P.
Powiązania:: https://bibliotekanauki.pl/articles/2084536.pdf
Data publikacji:: 2011
Wydawca:: Uniwersytet Warszawski. Wydział Geografii i Studiów Regionalnych
Tematy:: zmiany klimatyczne
polkula polnocna
promieniowanie sloneczne
izotop tlenu δ18O
prognozy
klimat
Źródło:: Prace i Studia Geograficzne; 2011, 47; 25-32
0208-4589
Pojawia się w:: Prace i Studia Geograficzne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Weighting alternatives for water stable isotopes: Statistical comparison between station- and firn/ice-records
Autorzy:: Hatvani, István Gábor
Kern, Zoltán
Powiązania:: https://bibliotekanauki.pl/articles/2046775.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: amount-weighted annual average
Antarctica
polar precipitation
snow accumulation
temperature proxy
vapor exchange
δ18O and δ2H records
Źródło:: Polish Polar Research; 2017, 38, 2; 105-124
0138-0338
2081-8262
Pojawia się w:: Polish Polar Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Isotopic investigation of nitrates in Horyniec-Zdrój waters
Autorzy:: Baran, Anna
Baran, Ireneusz
Gebus, Beata
Hałas, Stanisław
Powiązania:: https://bibliotekanauki.pl/articles/763339.pdf
Data publikacji:: 2015
Wydawca:: Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:: mineral and therapeutic waters
nitrate concentration
δ15N and δ18O in nitrates (NO3-)
Horyniec-Zdrój
Opis:: In this work the isotopes of oxygen and nitrogen were determined in nitrates of water samples collected in Horyniec Zdrój and they allowed the preliminary indication of the source of NO3– ion. The obtained δ15N and δ18O values of nitrates dissolved in the Róża III therapeutic water are +2.1, +13.1 ‰, respectively. They indicate the origin of NO3- ion from bacterial decomposition of organic matter which is abundant in the aquifer.Interpretation of the processes affecting the chemical and isotopic composition of investigated waters was possible by taking into account earlier isotopic analyzes as well as chemical composition, geological structure and hydrogeological conditions prevailing in the aquifer. The results and discussion presented in this paper have excluded the possible influence of external contaminants in Horyniec-Zdrój waters used for therapeutic purposes.
Źródło:: Annales Universitatis Mariae Curie-Skłodowska, sectio AAA – Physica; 2015, 70
0137-6861
Pojawia się w:: Annales Universitatis Mariae Curie-Skłodowska, sectio AAA – Physica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Elementy walidacji metody oznaczania δ18O i δD próbek ciekłych (EA-IRMS)
Validation of δ18O i δD determination method in aqueous samples (EA-IRMS)
Autorzy:: Janiga, M.
Bieleń, W.
Powiązania:: https://bibliotekanauki.pl/articles/1835465.pdf
Data publikacji:: 2017
Wydawca:: Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:: skład izotopowy tlenu
skład izotopowy wodoru
δ18O
δD
EA-IRMS
walidacja
oxygen isotopic composition
hydrogen isotopic composition
validation
Opis:: Celem pracy było wykonanie elementów walidacji metodyki oznaczeń składu izotopowego tlenu i wodoru próbek ciekłych (wody) przy użyciu spektrometru masowego połączonego z analizatorem elementarnym (EA-IRMS). Zarówno w przypadku oznaczeń składu izotopowego wodoru, jak i tlenu wykonano kalibrację przy zastosowaniu wzorca VSMOW2 oraz wyznaczono stretching factor (wykorzystując wzorzec SLAP2). Dla obydwu pierwiastków metody są dokładne (wartości rzeczywiste wzorca znajdują się w wyznaczonych przedziałach). Odchylenia standardowe powtarzalności i odtwarzalności są na niskim poziomie (dla tlenu: 0,15‰ i 0,21‰; dla wodoru: 1,2‰ i 1,3‰). Wartość niepewności pomiaru w przypadku oznaczeń składu izotopowego tlenu wynosi 0,569885% (czyli 0,310644‰ po przeliczeniu dla wzorca SLAP2), a w przypadku wodoru: 0,479804% (czyli 2,022375‰ po przeliczeniu dla wzorca SLAP2).
The aim of the study was to perform validation of a methodology of isotopic composition determinations of oxygen and hydrogen liquid samples (water) using a mass spectrometer combined with an elemental analyzer (EA-IRMS). For the determination of both the hydrogen and oxygen isotopic composition, calibration was performed by using VSMOW2 standard, and stretching factor was determined using the SLAP2 standard. For both elements methods are accurate (the actual value can be found at designated intervals). The standard deviations of repeatability and reproducibility are low (for oxygen 0.15‰ and 0.21‰, for hydrogen 1.2‰ and 1.3‰). The value of measurement uncertainty for the determination of the isotopic composition of oxygen is 0.569885% (or 0.310644‰ after calculation for the SLAP2 standard) and for hydrogen is 0.479804% (or 2.022375 ‰ after calculation for SLAP2 standard).
Źródło:: Nafta-Gaz; 2017, 73, 7; 473-478
0867-8871
Pojawia się w:: Nafta-Gaz
Dostawca treści:: Biblioteka Nauki

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