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    Wyświetlanie 1-7 z 7
    Tytuł:
    Mossbauer studies of Sołtmany meteorite - preliminary results
    Autorzy:
    Gałązka-Friedman, J.
    Szlachta, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/411513.pdf
    Data publikacji:
    2012
    Wydawca:
    Polskie Towarzystwo Meteorytowe
    Tematy:
    Mössbauer spectroscopy
    Sołtmany meteorite
    Baszkowka meteorite
    ordinary chondrites classification
    Opis:
    In Mossbauer spectra of the Sołtmany meteorite we identified four iron-bearing minerals: olivine, pyroxene, kamacite and troilite. The distribution of iron among these minerals is different in the Sołtmany meteorite from this distribution in the Baszkowka meteorite. As Sołtmany and Baszkowka meteorites are ordinary chondrites type L (both falls), differences in the distribution of iron over the four main iron-bearing mineral phases could be the basis for a new classification of L-type ordinary chondrites. Small amounts of taenite were also observed in the Sołtmany meteorite. The ratio of iron in kamacite and taenite in the Sołtmany meteorite was found to be about 3. No Fe3+ could be detected.
    Źródło:
    Meteorites; 2012, 2, No. 1-2; 73-77
    2299-0313
    2299-1220
    Pojawia się w:
    Meteorites
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    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:
    The Songyuan ordinary chondrite (China) - rich in alien rock fragments and its reclassification
    Autorzy:
    Borucki, J.
    Giro, L.
    Orłowski, R.
    Stępniewski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/2059203.pdf
    Data publikacji:
    2009
    Wydawca:
    Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
    Tematy:
    Songyuan
    meteorites
    ordinary chondrites
    classification
    rock fragments
    Opis:
    The Songyuan chondrite is composed mostly of minerals and chondrule types common in equilibrated ordinary chondrites. More distinctively, the Songyuan material includes numerous sintered cryptocrystalline rock lumps, possible chondrule precursors, and less frequent fragments of olivine-pyroxene basalt. The moderate porosity (estimated under the polarizing microscope at a few percent by volume) and un compacted metal grains, suggest that the meteorite came from very shallow horizons of the regolith. The shallow original position of the Songyuan fragment on its parent body is consistent also with the abundance of numerous euhedral crystals of the main meteoritic components present in the interstitial pores. They crystallized most probably from fluids migrating through the superficial horizons from the in ner parts of the Songyuan parent body. The structural characteristics and slight differentiation in olivine composition suggests a high degree of homogenization and, together with the median value of the fayalite content (26.2 š0.24 wt.%), corre sponds to the L5 chemical-petrologic group of equilibrated ordinary chondrites. More over, the homogenous extinction in the olivine crystals and the absence of multiple planar fractures indicate the lowest level of the shock metamorphism (S1), whereas the lack of any oxide rims around kamacite and troilite grains points to the lowest level of weathering (W0).
    Źródło:
    Geological Quarterly; 2009, 53, 2; 187-198
    1641-7291
    Pojawia się w:
    Geological Quarterly
    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:
    Petrography of the Baszkówka chondrite
    Autorzy:
    Siemiątkowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/2059299.pdf
    Data publikacji:
    2001
    Wydawca:
    Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
    Tematy:
    Baszkówka
    ordinary chondrites
    chondrules
    structure
    petrography
    classification
    origin
    Opis:
    The Baszkówka chondrite comprises chondrules, individual crystals of olivine, xenomorphic concentrations of kamacite and troilite, matrix and pores up to 3.0 mm in diameter; porosity reaches 20% by volume. Measurements of 697 chondrules in an area of 250 m2 enabled distinction of three populations. The chondrules and olivine crystals have been sintered at high temperatures. Six structural types showing transitions between porphyritic and granular structures have been discriminated. Rims showing a similar diversity surround about 10% of chondrules. The composition and structure of the chondrules suggest a source from the nebular dust disk around the Sun. The abudance of voids and their relatively large size and a lack of fissures, indicate a small size of the host body, which must have been derived from an early phase of protoplanet formation.
    Źródło:
    Geological Quarterly; 2001, 45, 3; 263-280
    1641-7291
    Pojawia się w:
    Geological Quarterly
    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 1-7 z 7

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