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Jak klasyfikujemy chondryty zwyczajne?

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Szyszka M.

Acta Societatis Metheoriticae Polonorum

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2014

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tom 5

149-154

EN

Modern systems of classification has been started in XIX century. However the true progress was began at 60’s and 70’s of XX century. In this time was started modern analythic methods such as: chemical, mineralogic and pretrographic analysis. For this progress fostered also a large number of found meteorites from Antarctica. This article will be concerned about a classification of ordinary chondrites. Acquired meteorite from moroccan searchers. Has been examined and classified. The scheme of this works are presented below.

PL

Współczesny system klasyfikacji meteorytów pochodzi z końca XIX w. Prawdziwy rozwój nastąpił dopiero w latach 60 i 70 XX, kiedy pojawiły się nowoczesne metody badawcze, umożliwiające bardziej kompleksowe analizy petrologiczne, zwłaszcza chemiczne. Rozwojowi temu też sprzyjała olbrzymia ilość meteorytów znajdowanych na Antarktydzie. Niniejsza praca przybliży czytelnikowi sposób klasyfikacji meteorytów kamiennych typu chondryty. Materiał jako przykład badawczy posłużył meteoryt kamienny zakupiony w 2012 w Maroku.

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Euhedral crystals in interstitial pores of the Baszkówka and Mt. Tazerzait L5 chondrites

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Wlotzka F. , Otto J.

Geological Quarterly

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2001

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tom Vol. 45, No 3

257-262

EN

Euhedral to anhedral crystals of the main meteoritic minerals are found in interstitial pores of the unshocked L5 chondrites Baszkówka and Mt. Tazerzait. The composition of these pore minerals is the same as elsewhere in the meteorite. They must have grown from a vapour phase during metamorphic equilibration of the meteorite minerals. The pores are primary features, i.e. open space remaining after compaction of the constituents of the meteorite.

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Comparative analysis of the Baszkówka and Mt. Tazerzait chondrites: genetic conclusions based on astrophysical data and the mineralogical and petrological data

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Pilski A. S. , Przylibski T. A. , Zagożdżon P. P.

Geological Quarterly

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2001

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tom Vol. 45, No 3

331-342

EN

The L5 chondrites Baszkówka and Mt. Tazerzait are characterised. Their astronomical, mineralogical and petrological characteristics confirm that these meteorites are similar. They could be derived from the same parent body, though from the different depths below its surface. A third meteorite - the Tjerebon - might have arisen from the same swarm of meteoroids. The parent body to these meteorites in the asteroid belt can not be established at present. The porosity, of these chondrites suggests that they formed close to the surface of their parent asteroid. The process of formation of the parent rock of the Baszkówka chondrite is similar in some respects to sedimentation of a weakly compacted terrestrial sandstone. Thus, a two-stage geological history may be envisaged: firstly formation of the component minerals and mineral aggregates of this meteorite. Then, later in a different environment, the accretion of fragments of this parent material, together with a small amount of matrix, into a strongly porous sedimentary rock.

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Petrologiczna i mineralogiczna charakterystyka chondrytu węglistego NWA 4967

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Szurgot M.

Acta Societatis Metheoriticae Polonorum

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2014

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tom 5

121-148

EN

NWA 4967 carbonaceous chondrite thin section was investigated by optical microscopes in transmission and in reflection. Minerals of the meteorite have been identified and microstructure analyzed. Chondrules, matrix, metal phases, AOAs and CAIs are constituents of the rock, as expected. Olivine, clinopyroxene, orthopyroxene, troilite, kamacite and feldspar have been detected. Various types of chondrules including: PO, POP, PP, RP, BO, C, GOP and GO chondrules were identified. Compositional zoning of some olivines, diagnostic cracks in pyroxenes, clinopyroxene twins, and chondrule rims have been observed and analyzed. Our previous EPMA and Raman data as well as present optical data confirm that NWA 4967 belongs to CO3.2 chondrites, as previously classified.

5

K/Ar dating and stable isotope analysis of the Baszkówka and Mt. Tazerzait L5 chondrites

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Hałas S. , Wójtowicz A.

Geological Quarterly

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2001

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tom Vol. 45, No 3

315-318

EN

We have determined the content of 40Ar* (1.49 nmol/g) and 4He (1.75 nmol/g) in the Baszkówka meteorite by static vacuum mass spectrometry. The radiogenic argon content was calculated from the measured argon spectrum using the equation: 40Ar* = 40Ar - 295.536Ar assuming a potassium content of 680 ppm wgt. We have obtained K/Ar ages of 3.78 Ga for the chondrules and 3.47 Ga for a bulk sample of Baszkówka. A similar 4He content (1.47 nmol/g) but larger 40Ar* (2.32 nmol/g) content was found for the Mt. Tazerzait bulk sample. The K/Ar age of this meteorite on the basis of the K content (732 ppm) is 4.34 Ga. Sulphur isotope analysis of troilite specimens from both meteorites reveals essentially negative delta 34S values: -1.25š0.06o/oo for Baszkówka and -1.18š0.06o/oo for Mt. Tazerzait expressed on the V-CDT scale. This indicates that both chondrites may have a common origin. The oxygen isotope data (delta 18O = 4.88š0.03o/oo and delta 17O = 3.66š0.10o/oo) suggests that Baszkówka belongs to the L chondrites.

6

A study on chemical composition of Baszkówka and Mt. Tazerzait chondrites

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Dybczyński R. , Chwastowska J. , Danko B. , Kulisa K. , Polkowska-Motrenko H. , Samczyński Z. , Sterlińska E. , Szopa Z.

Geological Quarterly

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2001

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tom Vol. 45, No 3

289-302

EN

The elemental contents of two new meteorites, Baszkówka (Poland, 1994) and Mt.Tazerzait (Niger, 1991), were studied by instrumental and radiochemical neutron activation analysis (NAA), supplemented in the case of some elements by gravimetric, titrimetric, spectrophotometric and atomic absorption spectrometric measurements. In total 28 elements were determined for each meteorite. A striking similarity in the bulk chemical composition of the two meteorites was observed. In the case of Baszkówka some study of the elemental contents of the magnetic fraction and the distribution of elements between kamacite and taenite phases was also made. This study confirms that Baszkówka and Mt. Tazerzait are generally more similar to L chondrites than to any other class of chondrites. However both meteorites show also some distinctive features (e.g very low Hg content), distinguishing them from all other L chondrites known. Both meteorites may derive from a common parent body, which may be different from that typical for other chondrites.

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Microscopic studies of NWA4047 meteorite

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Szurgot M. , Polański K. , Krystek M.

Scientific Bulletin. Physics / Lodz University of Technology

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2006

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tom Vol. 27

61-76

EN

Elemental and mineral composition of NWA4047 meteorite found in 2005 has been studied by analitical electron microscopy and optical microscopy. It was established that the main meteorite minerals: olivines, pyroxenes, kamacite and taenite as well as troilite identified in the sample represent extraterrestrial minerals typical of the ordinary chondrite of high iron content. Chemical and mineral composition, petrologic types of chondrules, their abundance and sizes, the presence of troilite veins and abundance of nonoxidised iron phases confirm H class of this chondrite, i.e. olvine-bronzite class.

PL

Badano skład chemiczny i mineralny meteorytu NWA 4047. Zanalizowano chondry i ciasto skalne tego meteorytu. Obecność chondr, żył troilitowych oraz faz żelazo-niklowych: kamacytu i troilitu świadczą o pozaziemskim pochodzeniu badanej skały i przynależności tego meteorytu do chondrytów żelaznych o dużej zawartości żelaza, tj. do klasy chondrytów oliwinowo-bronzytowych.

8

Morocco meteorite falls and finds: some statistics

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Ibhi A.

International Letters of Chemistry, Physics and Astronomy

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2014

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tom Vol. 1

18-25

EN

Since the first recorded discovery of a meteorite in 1937 near the Mrirt village (Khenifra, Morocco), a total of 946 authenticated meteorites have been recorded in Morocco. The material, including 10 observed falls, comprises 918 stones, 13 irons and 15 stony-irons. A low ratio of falls to finds (represent only 0.01 % of the Moroccan declared meteorites) compared with other countries (e.g., USA 14.3 %). However the rate of recovery of meteorites (falls + finds) in Morocco exceeds that of most other countries of similar size and range of climatic conditions. More than 95 % of documented meteorites from Morocco have been recovered from Eastern Morocco (Eastern Sahara Moroccan) including many rare types. This Region has proved to be one of the most prolific areas in the world for meteorite finds.

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The investigation of genetic relationship between the Baszkówka and Mt. Tazerzait chondrites by NAA and other methods

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Dybczyński R. , Borucki J. , Danko B. , Kulisa K. , Polkowska-Motrenko H. , Samczyński Z. , Stępniewski M. , Szopa Z. , Tanida K.

Chemia Analityczna

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2001

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tom Vol. 46, No. 4

477-488

EN

The similarity of two meteorites, Baszkowka (Poland, 1994) and Mt. Tazerzait (Niger, 1991), was studied by instrumental and radiochemical neutron activation analysis supplemented by mercury determination with the aid of an automatic mercury analyzer yielding data for 23 elements. The bulk composition of both meteorites is nearly identical within the experimental error. Their composition is also similar to the mean composition of L chondrites but there are marked deviations in the cases of Pd, Os, Pt, Cu and Hg. It seems also that both meteorities are slightly enriched in light rare earth elements (REE) and slightly depleted in heavy REE in comparison with L chondrites. This study supports earlier suggestions based on petrological properties, abundance of noble gases and their isotopic composition, gas retention ages and cosmic ray exposure ages, that these two chondrites have the same origin and the common parent body. It cannot be excluded that this parent body is different from that typical for all other known L chondrites.

PL

Stosując instrumentalną i radiochemiczną neutronową analizę aktywacyjną oraz automatyczny analizator rtęci badano podobieństwo dwóch meteorytów o nazwach: Basz-kówka (Polska, 1994) oraz Mt. Tazerzait (Niger, 1991). Na podstawie oznaczenia 23 pierwiastków stwierdzono, że całościowy skład obu meteorytów jest niemal identyczny w granicach błędu doświadczalnego. Ich skład jest też podobny do średniego składu chondrytów typu L, jednakże z istotnymi odchyleniami w przypadku Pd, Os, Pt, Cu i Hg. Wydaje się także, że oba meteoryty są nieznacznie wzbogacone w lekkie i nieznacznie zubożone w ciężkie ziemie rzadkie w stosunku do chondrytów L. Badania te potwier-dzająwcześniejsze sugestie, oparte na własnościach petrologicznych, obecności gazów szlachetnych i ich składu izotopowego, wieku zatrzymania gazu oraz wieku kosmicznego napromieniowania że oba chondryty mają takie samo pochodzenie i wspólne ciało macierzyste. Nie jest wykluczone, że to ciało macierzyste różni się od ciała macierzystego wszystkich innych chondrytów typu L.

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Microscopic investigations of Gold Basin and El Hammami chondrites

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Szurgot M. , Polański K.

Scientific Bulletin. Physics / Lodz University of Technology

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2007

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tom Vol. 28

79-94

EN

Elemental and mineral composition of Gold Basin and El Hammami meteorites discovered in 1995 and 1997 have been studied by analytical electron microscopy and optical microscopy. It was established that the main meteorite minerals: olivines, pyroxenes, kamacite and taenite as well as troilite identified in the samples represent extraterrestrial minerals typical of the ordinary chondrites. Feldspars represented by plagioclase, orthoclase, magnetite, calcite, chromite and silica have been also present in the studied samples. Chemical and mineral composition, iron content, petrologic types of chondrules, their abundance and sizes, the presence of troilite veins and abundance of nonoxidised iron phases confirm H class of El Hammami chondrite, i.e.. olvine-bronzite class, and L class of Gold Basin, i.e. olivine-hyperstene class.

PL

Badano skład chemiczny i mineralny meteorytów Gold Basin i El Hammami. Zanalizowano chondry i ciasto skalne. Obecność chondr oliwinowych, chondr piroksenowych, żył troilitowych oraz faz żelazo-niklowych: kamacytu i troilitu świadczą o pozaziemskim pochodzeniu badanych skał. Oprócz minerałów najbardziej rozpowszechnionych w meteorytach takich jak: oliwin, piroksen, kamacyt, taenit i troilit wykryto także plagiklazy, magnetyt, kalcyt, chromit, ortoklaz i krzemionkę. Zgodnie z uprzednią klasyfikacją Gold Basin jest chondrytem klasy L o niskiej zawartości żelaza, a El Hammami chondrytem typu H zawierającym dużo żelaza.

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Średni ciężar atomowy chondrytu Sołtmany, chondrytów L6 i minerałów pozaziemskich

72%

Szurgot M.

Acta Societatis Metheoriticae Polonorum

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2015

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tom 6

107-128

EN

Mean atomic weight Amean of Sołtmany (L6, S2, W0) ordinary chondrite, various L6 chondrites such as: Jesenice, Girgenti, Leedey, Bruderheim, Holbrook and Modoc, as well as LL, L and H chondrites has been determined using literature data on chemical composition of the meteorites. Relationship between mean atomic weight and Fe/Si atomic ratio for ordinary chondrites has been established. It was shown that Sołtmany’s Amean = 23.97 is close to mean atomic weight of L chondrites Amean = 23.70, and is close to mean atomic weight of L6 chondrites Amean = 24.06±0.16. It has been established that Sołtmany’s Fe/Si atomic ratio (Fe/Si = 0.588) is close to Fe/Si ratio for L6 chondrites (Fe/Si = 0.598). This means that Sołtmany belongs to L6 chondrites, as previously classified. Using discovered by the author (Szurgot, 2015) dependence between mean atomic weight and uncompressed density of planetary matter it was established that grain density of Sołtmany meteorite should be equal to 3.56±0.12 g/cm3, which is about 4% lower than previously estimated by porosity data. Mean atomic weight of extraterrestrial minerals present in ordinary chondrites and in Sołtmany meteorite have been also determined.

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Średni ciężar atomowy chondrytów LL5: Siena, Hautes Fagnes i NWA 7915

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Szurgot M.

Acta Societatis Metheoriticae Polonorum

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2016

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tom 7

133-143

EN

Mean atomic weights Amean of Siena (LL5, fall 1794), Hautes Fagnes (LL5, S1, W1, find 1965) and NWA 7915 (LL5, S2, W3, find 2010) ordinary chondrites have been determined using literature data on chemical composition of the meteorites and using relationship between mean atomic weight and Fe/Si atomic ratio (Szurgot 2015). It was shown that NWA 7915 Amean = 22.80 is close to mean atomic weight of LL chondrites (Amean = 23.00), and is close to mean atomic weight of LL chondrite falls (Amean = 22.90, Szurgot 2015). NWA 7915’s Fe/Si atomic ratio (0.529) leads to Amean = 23.28 which is close to the value determined by bulk composition. This means that NWA 7915 belongs to LL5 chondrites, as previously classified (Brawata et al. 2014). Mean atomic weight Amean of Hautes Fagnes determined by bulk composition is between 23.11 and 23.35. Lower Amean value is close to Amean of LL chondrites, but higher value is the same as Amean of intermediate L/LL chondrites (23.34 for L/LL, Szurgot 2016). Hautes Fagnes Fe/Si atomic ratio and Amean(Fe/Si) are identical with those for NWA 7915 (Fe/Si = 0.529, Amean = 23.28). Amean data indicate that Hautes Fagnes can belong to LL5 chondrites, as previously classified (Vandeginste et al. 2012) or can be one of L/LL chondrites. Mean atomic weight of Siena meteorite is much higher than expected for LL chondrite. Siena’s bulk composition gives Amean = 24.47, and Amean(Fe/Si) dependence gives Amean = 24.45 (Fe/Si = 0.7345). Using dependence between mean atomic weight and grain density (Szurgot 2015) leads to Amean = 23.24 (dgr = 3.46 g/cm3, Macke 2010), and using dependence between Amean and magnetic susceptibility (Szurgot 2016) gives Amean = 23.53±0.13 (logc = 4.65±0.09, Macke 2010). Bulk composition and Fe/Si ratio indicate that Siena has the same Amean as intermediate H/L chondrites, for which Amean = 24.3 (Szurgot 2016). Grain density indicates rather L/LL intermediate group for Siena, and magnetic susceptibility indicates intermediate L/LL or L chondrites (23.34 for L/LL, and 23.67 for L, Szurgot 2016). Mean atomic number Zmean, and Amean/Zmean ratio of the three meteorites have been also determined. Siena’s Zmean = 12.104, Hautes Fagnes Zmean = 11.445–11.562, and NWA 7915’s Zmean = 11.293. Amean/Zmean ratios are: 2.022 for Siena, 2.019–2.020 for Hautes Fagnes, and 2.019 for NWA 7915.