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Wyszukujesz frazę "ordinary chondrites classification" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Porównawcze badania mössbauerowskie meteorytów: Sołtmany (L6), Chelyabinsk (LL5) i Grzempy (H5)
Mössbauer comparative studies of the Sołtmany (L6), Chelyabinsk (LL5) and Grzempach (H5) meteorites
Autorzy:
Szlachta, Karol
Gałązka-Friedman, Jolanta
Woźniak, Marek
Powiązania:
https://bibliotekanauki.pl/articles/1033011.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
Chelyabinsk (LL5)
Grzempy (H5)
Mössbauer spectroscopy
Sołtmany (L6)
classification of ordinary chondrites
meteorites
Opis:
Mössbauer studies of Chelyabinsk (LL5), Sołtmany (L6) and Grzempy (H5) show that the main iron bearing minerals in these meteorites are: Fe-Ni, troilite, olivine and pyroxene. Based on Mössbauer absorption area of different mineral phases, new set of parameters for classification of the ordinary chondrities were introduced. The most promising parameters are: the ratio of the olivine to pyroxene areas and the ratio of the silicate to metallic areas.
Źródło:
Acta Societatis Metheoriticae Polonorum; 2014, 5; 115-120
2080-5497
Pojawia się w:
Acta Societatis Metheoriticae Polonorum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Próby klasyfikowania chondrytów zwyczajnych przez zastosowanie spektroskopii mössbauerowskiej
Attempts of classification of ordinary chondrites by application of Mössbauer spectroscopy
Autorzy:
Gałązka-Friedman, Jolanta
Woźniak, Marek
Duda, Przemysław
Jakubowska, Martyna
Bogusz, Patrycja
Karwowski, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/1032381.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
Mössbauer spectroscopy
classification of meteorites
ordinary chondrites
Opis:
Mössbauer spectra of equilibrated ordinary chondrites consist of two sextets due to magnetically ordered iron present in metallic phases and troilite and two doublets due to paramagnetic iron present in olivines and pyroxenes. The Mössbauer spectral areas of the different mineralogical phases in meteorites are proportional to the number of iron ions present in olivines, pyroxenes, metallic phase and troilite. This property of Mössbauer spectra was the basis for constructing various methods for the classification of ordinary chondrites. Review of these methods will be presented.
Źródło:
Acta Societatis Metheoriticae Polonorum; 2019, 10; 23-28
2080-5497
Pojawia się w:
Acta Societatis Metheoriticae Polonorum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
NWA 14360 – Nowy meteoryt z Nigru
A new meteorite from Niger: NWA 14360
Autorzy:
Karwowski, Łukasz
Szopa, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/2034032.pdf
Data publikacji:
2022-03
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
ordinary chondrites
NWA 14360
meteorite
meteorites classification
Opis:
The new meteorite was bought as one single stone in 2019 from a dealer in Niger by Tomasz Jakubowski. The meteorite has fusion crust. It contains chondrules of different types with dominance of barred olivine chondrules, with diameter to 1.5 mm. Px and Ol are 78.1 vol%. of the meteorite mass. Pl is up 11.8 vol%. Average fayalite content is 24.93. Metallic phases are 3.0 vol%. Troilite is up to 5.9 vol%. Spinel (Cr-spinel) is up to 0.9 vol%. Average content of the secondary Fe-rich minerals (e.g. hydroxides) is 0.4 vol%. Feldspar composition is: Ab80.2Or5.0An14.8. Mean content of Al2O3, MgO and TiO2 in chromium spinel is 6.70 wt%, 2.05 wt% and 2.02 wt%, respectively. Metal phases are kamacite and tetrataenite. The kamacite has a Ni content in the range 5.83–6.81 wt%, while the Co content is in the range 0.39 to 0.56 wt%. Tetrataenite is has Ni content from 49.68 to 50.46 wt%, and Co up to 0.05 wt%. High-Ca monoclinic pyroxene, similar to diopside, is very rare. Accessory minerals are: chlorapatite and merrylite. Base on chemistry and petrography, the meteorite is classified as ordinary chondrite (L5). The main mass, a 9190 g specimen, is in Krzysztof Socha private collection. Small fragments with the total mass 71 g are stored in Museum of Earth Sciences (catalogue no: WNoZ/Mt/110) at University of Silesia in Katowice, Poland. 39 g was used for thin-section preparation and spectroscopic investigation (Mössbauer spectroscopy).
Źródło:
Acta Societatis Metheoriticae Polonorum; 2022, 13; 47-59
2080-5497
Pojawia się w:
Acta Societatis Metheoriticae Polonorum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metoda 4M – nowe zastosowanie spektroskopii mössbauerowskiej w klasyfikacji zrównoważonych chondrytów zwyczajnych
4M method – the new application of Mössbauer spectroscopy for classification of equilibrated ordinary chondrites
Autorzy:
Woźniak, Marek
Karwowski, Łukasz
Gałązka-Friedman, Jolanta
Duda, Przemysław
Jakubowska, Martyna
Bogusz, Patrycja
Powiązania:
https://bibliotekanauki.pl/articles/1033156.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
4M method
Cluster Analysis
Mahalanobis distance
Multidimensional Discriminant Analysis
Mössbauer spectroscopy
Principal Components Analysis
meteorites
meteorites classification
ordinary chondrites
Opis:
The 4M method aims to determine the type of equilibrated ordinary chondrite only on the basis of the Mössbauer spectrum of the investigated meteorite. Mössbauer spectrum of non-weathered ordinary chondrite is comprised of four sub-spectra: two doublets and two sextets. One of the doublets consists of a signal from iron present in olivine and the other consists of a signal from iron present in pyroxene. Sextets on the other hand, contain signals from magnetically ordered iron. One sextet is related to the metallic phase (kamacite, taenite), whereas the second is related to troilite. A third of doublets, which emerges in weathered ordinary chondrites, is related to products of the oxidation of iron present in metallic phase. The spectral areas of olivine, pyroxenes, metallic phase and troilite, which were obtained from Mössbauer spectrum are proportional to the number of iron atoms present in relevant mineral phases. Some Mössbauer groups were inspired by this fact to construct different methods to determine the type (H, L, or LL) of investigated meteorites (Gałązka-Friedman et al. 2019, Hyp. Inter. 241(1)). However, these methods, based on subjective criteria, were only qualitative. Our group elaborated a quantitative method, which is based on objective criteria. We called it the "4M method" (where M are derived from meteorites, Mössbauer spectroscopy, multidimensional discriminant analysis (MDA), Mahalanobis distance) (Woźniak et al. 2019). This method was using only the Mössbauer experimental data, to which it applied advanced statistical methods. The base, which was created from Mössbauer data, consisted of three clusters H, L, LL. These clusters were constructed with sets of 4-dimensional vectors. The vectors are comprised of spectral areas of Mössbauer spectrum: ol (value proportional to iron present in olivine), pyr (value proportional to iron present in pyroxene), met (value proportional to iron present in metallic phase), tr (value proportional to iron present in troilite). To determine the type of investigated ordinary chondrite, its ol, pyr, met and tr values with average values of variables obtained for clusters H, L and LL need to be compared. The comparison can be performed with the use of MDA and Mahalanobis distance. Once Mahalanobis distance of the investigated meteoriteis is known, the level of similarity to three types of ordinary chondrites can be calculated. Examples of such calculations were performed for seven ordinary chondrites: Goronyo, Carancas, New Concord, NWA 7733, Leoncin, Sołtmany and Pułtusk. They were made with the use of the new base composed of 62 non-weathered ordinary chondrites. All results obtained with the 4M method yielded results consistent with traditional mineralogical methods.
Źródło:
Acta Societatis Metheoriticae Polonorum; 2020, 11; 125-140
2080-5497
Pojawia się w:
Acta Societatis Metheoriticae Polonorum
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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