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    Wyświetlanie 1-9 z 9
    Tytuł:
    Northwest Africa 7915: A New approved LL5 chondrite from Morocco
    Autorzy:
    Brawata, M.
    Kryza, R.
    Jakubowski, T.
    Przylibski, T. A.
    Ćwiąkalski, J.
    Łuszczek, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/411506.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Meteorytowe
    Tematy:
    chondrite
    NWA 7915
    Morocco
    chondrule
    chondrite chemistry
    chondrite weathering
    Opis:
    A 415 g single meteorite was purchased in 2010 by T. Jakubowski from a dealer in Morocco. The meteorite was isometric in shape, ca. 8 cm in size, with distinct regmaglypts on the original ablated surface, and covered mostly in primary crust with one broken surface. The weight of the sample studied was 69 g. The meteorite is composed of several types of chondrules including porphyritic-Ol-Px, barred-Ol, radial-Px, granular and cryptocrystalline with distinct and diffused (not sharp) boundaries, and opaque grains and aggregates, enclosed in a very fine-grained matrix. The average compositions of minerals are: olivine (both in chondrules and matrix) − Fo70.4Fa29.1Te0.5, pyroxenes, represented by Mg-Fe (Ca-poor) orthopyroxene (and minor clinopyroxene?) − En73.9Fs24.1Wo2.0, feldspars (small in the matrix and in barred chondrules), with An12-37, and Or~3-4, taenite − Fe 70.80, Ni 25.50 and Co 1.67 wt. %, troilite − Fe0.98S1.00, chromite (Fe2+ 0.96Mg0.12Mn0.01Zn0.01) (Cr1.52Al0.23Fe3+ 0.02Ti0.10Si0.02)O4; altered accessory minerals including apatite and iron-rich secondary phases have also been identified and analyzed. The meteorite is of petrologic type 5, as evidenced by the observed recrystallization of the matrix, relatively good preservation of the chondrule structures, homogeneous composition of olivine and pyroxene, and the presence of only secondary small feldspar grains. The shock stage, S2, is based on the presence of undulatory extinction and irregular fractures in olivine crystals. The weathering grade, W3, is confirmed by the observation that kamacite is totally altered into secondary iron phases, whereas Nirich taenite, and troilite are only partly weathered. The specimen shows many bulk- and mineral-chemical parameters corresponding, mostly, to the LL chondrite group (e.g., Fe/SiO2 0.49, SiO2/MgO 1.62, Fa in olivine 29.05). However, concentrations of several other elements, including REE, are not fully consistent with the average values for the LL ordinary chondrites. Apparently, the parent body of the studied NWA 7915 meteorite was depleted in Dy, Tm, and Yb, compared to typical LL-type ordinary chondrite parent bodies. Also, relatively high concentrations of other elements, including Ba and Sr, have been measured, which may result from terrestrial weathering in hot desert conditions. The meteorite has been classified as LL5 ordinary chondrite, S2, W3, and registered in the Meteoritical Society database as NWA 7915. The type specimen is deposited in the Mineralogical Museum of the University of Wrocław.
    Źródło:
    Meteorites; 2014, 3, No. 1-2; 45-58
    2299-0313
    2299-1220
    Pojawia się w:
    Meteorites
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Bulk chemical composition of Sołtmany chondrite
    Autorzy:
    Przylibski, T. A.
    Łuszczek, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/411498.pdf
    Data publikacji:
    2012
    Wydawca:
    Polskie Towarzystwo Meteorytowe
    Tematy:
    meteorite
    ordinary chondrite
    L-chondrite
    bulk composition
    meteorite fall
    observed fall
    Opis:
    The authors examined the bulk chemical composition of the Sołtmany chondrite which fell on April 30th, 2011 in Northern Poland. Based on the analysis of 47 elements, it was concluded that Sołtmany is representative of L-type of ordinary chondrites. However, compared to the average values observed in other L-type ordinary chondrites, Sołtmany displays higher content of Ni, P, Cd, Pb, and As. The Ni and P content closely resembles typical values for H-type ordinary chondrites. Furthermore, Sołtmany displays other distinct properties including very low Zn content and lower contents of Mo and Zr than the average values found in other L-type ordinary chondrites. Consistent with other L-type ordinary chondrites, the absolute content of REE in Sołtmany is higher than that of CI-type carbonaceous chondrites while the REE trend lines for both Sołtmany and CI-chondrites are similar. Due to similar times of year of when both falls took place and the proximity of their strewn fields, the chemical composition of Sołtmany was compared with that of Jesenice, an L6 ordinary chondrite which fell on April 9th, 2009 in Europe. The analysis led to a conclusion that Sołtmany and Jesenice are not launch-paired. Nevertheless, even though they do not represent fragments of the same meteoroid, their origin on a common parent body (an asteroid – planetesimal) cannot be conclusively ruled out on the sole basis of their bulk chemical composition.
    Źródło:
    Meteorites; 2012, 2, No. 1-2; 31-37
    2299-0313
    2299-1220
    Pojawia się w:
    Meteorites
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sołtmany meteorite
    Autorzy:
    Karwowski, Ł.
    Powiązania:
    https://bibliotekanauki.pl/articles/411492.pdf
    Data publikacji:
    2012
    Wydawca:
    Polskie Towarzystwo Meteorytowe
    Tematy:
    meteorite
    ordinary chondrite
    L6 chondrite
    meteorite fall
    hammer meteorite
    Warmia-Masuria Province
    Sołtmany village
    Opis:
    This paper presents the results of a mineralogical and petrological study of the Sołtmany meteorite, which fell on April 30, 2011 in northern Poland. The meteorite was found almost immediately after it fell and has been little altered by weathering. Sołtmany is not the only observed fall of an L6 chondrite over Europe in the past few years. The preceding fall of this type, Jesenice (Slovenia), was also witnessed in April of 2009. However, it was not until several weeks after the fall that the first specimen of Jesenice was found, whereas Sołtmany was collected after a few minutes and submitted for analysis within a couple of days. The author presents mineral and petrographic features and chemical characteristics of mineral phases in Sołtmany. The mineral components are represented by metallic phases (kamacite, taenite, tetrataenite, native copper), as well as chromite, olivine, low and high-calcium pyroxene, feldspar, chlorine-bearing apatite, and merrillite. This study also describes the texture of the meteorite and takes notice of a low number of preserved chondrules and the presence of oval chondrule like areas, which exhibit a metamorphosed, recrystallized texture. Sołtmany was classified as an L6 ordinary chondrite with a weathering grade of W0. A shock stage S2 was determined on the basis of undulose extinction and lack of planar fractures in olivine crystals.
    Źródło:
    Meteorites; 2012, 2, No. 1-2; 15-30
    2299-0313
    2299-1220
    Pojawia się w:
    Meteorites
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A new classification of Nyirábrany, an ordinary chondrite from Hungary
    Autorzy:
    Mészáros, M.
    Kereszturi, A.
    Ditrói-Puskás, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/411486.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Meteorytowe
    Tematy:
    chondrite
    classification
    L and LL chondrites.
    Opis:
    The Nyirábrany meteorite is an ordinary chondrite from Hungary that fell in 1914 and, to date, has been studied very little. The aim of this work was to carry out a more detailed examination of this meteorite (using optical polarization microscope, energy dispersive X-ray spectroscopy and Raman micro spectroscopy) and re-investigate its previous classification as an LL5 type ordinary chondrite, moreover to complete its classification with a shock stage and a weathering grade. Our new results indicate that Nyirábrany could be a transition type between the L and LL chondrites. The main mineral phases of Nyirábrany are olivine, pyroxene and opaque minerals (e.g. Fe-Ni metal, troilite, chromite), minor constituents are plagioclase, Cl-apatite, cristobalite and glass. The Fe-Ni metal content (1.32 vol%) of Nyirábrany is typical of the LL group, the Fa content of olivines (26.71 mol%) is between the range of the L and LL types, while the Fs-content of the low-Ca pyroxenes (20.51 mol%) is typical of the L-chondrites. Chondrules appear in different sizes, mineral compositions and textures. The textural and mineralogical features (e.g. mostly homogeneous silicate minerals, dominance of clinopyroxenes, recrystallized matrix, well-defined chondrules) indicate petrological type 4-5 for Nyírábrány. The shock stage and the weathering grade of this meteorite were examined for the first time. On the basis of the observed optical and textural features of the olivine grains (e. g. sharp optical extinction, irregular and planar fractures) Nyirábrany has an S2 shock stage. About 30–40% of the opaque phases are affected by oxidation, which shows a W2 weathering grade.
    Źródło:
    Meteorites; 2014, 3, No. 1-2; 19-32
    2299-0313
    2299-1220
    Pojawia się w:
    Meteorites
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The meteorite fall near Boumdeid, Mauritania, from September 14, 2011
    Autorzy:
    Buhl, S.
    Toueirjenne, C.
    Hofmann, B.
    Laubenstein, M.
    Wimmer, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/411504.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Meteorytowe
    Tematy:
    Boumdeid (2011)
    meteorite fall
    Mauritania
    trajectory scenario
    L6 chondrite
    cosmogenic radionuclides
    Opis:
    On the evening of September 14, 2011 at 21:00 GMT a bright bolide was observed by hundreds of eyewitnesses in the area north and west of the town of Kiffa, in the department of Assaba, in south Mauritania. A terminal fragmentation and sound phenomena were observed near the end point of the trajectory. At least one mass of 3.5 kg was observed to impact and recovered the morning after the fall near Boumdeid (or Bou Mdeid), around 60 km north of Kiffa. Subsequently a large number of eyewitness accounts were recorded and mapped by GPS. The present paper provides a scenario for the trajectory of the Boumdeid (2011) meteorite based on the available parameters and wind data at the relevant altitudes. In addition the paper presents the results of the mineralogical and chemical analysis of the recovered meteorite which is consistent with a classification as ordinary chondrite of type L6, shock stage S2, and a weathering grade of W0. Following its analysis and classification, the meteorite was published under the official name Boumdeid (2011) in Meteoritical Bulletin, no. 100, MAPS 49(8), (2014). Gamma ray spectroscopy was conducted 84 days after the fall and the detection of short-lived radionuclides such as 56Co and 46Sc confirmed the recency of the event. Derived from the data of 60Co, 54Mn and 22Na the approximate preatmospheric radius of the meteorite body was 10–20cm. The report is also intended to serve as a case example for post-event data recovery and trajectory reconstruction in areas not covered by sky-camera networks and with limited scientific infrastructure.
    Źródło:
    Meteorites; 2014, 3, No. 1-2; 5-18
    2299-0313
    2299-1220
    Pojawia się w:
    Meteorites
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Primitive enstatite achondrites
    Autorzy:
    Pilski, A. S.
    Przylibski, T. A.
    Łuszczek, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/411494.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Meteorytowe
    Tematy:
    Acapulcoite
    lodranite
    winonaite
    brachinite
    ureilite
    metachondrite
    primitive achondrite
    enstatite chondrite
    primitive enstatite achondrite
    Opis:
    Conclusions drawn from the breadth of analytical data on primitive achondrites and enstatite chondrites paired with results of research performed by the authors have led the authors to propose the establishing of a new group of meteorites: primitive enstatite achondrites. The group is defined as the residual remaining after the partial melting of their protolith, which, in the case of primitive enstatite achondrites, is the parent body of enstatite chondrites. In this article are characterized textural features and characteristics of their mineral, chemical, and isotopic composition. The most important of these defining features are the presence of relic chondrules and/or triple junctions of crystal faces, as well as characteristic atomic and molar ratios of main elements: Si, Al, Fe, Mg, Mn and Ca, and particularly the molar ratios Fe/Mn and Fe/Mg. Another important characteristic is the isotopic composition of entrained noble gases, especially ratios of the heaviest of the isotopes and oxygen isotopes, whose values should be close to that typical for enstatite chondrites. It seems likely that the first meteorite to be classified as primitive enstatite achondrite will be the Zakłodzie enstatite achondrite.
    Źródło:
    Meteorites; 2011, 0, 0; 9-21
    2299-0313
    2299-1220
    Pojawia się w:
    Meteorites
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cosmogenic radionuclides in the Sołtmany (L6) meteorite
    Autorzy:
    Laubenstein, M.
    Giampaoli, A.
    Janowski, P.
    Mietelski, J. W.
    Powiązania:
    https://bibliotekanauki.pl/articles/411508.pdf
    Data publikacji:
    2012
    Wydawca:
    Polskie Towarzystwo Meteorytowe
    Tematy:
    meteorite
    ordinary chondrite
    short-lived radionuclides
    cosmogenic radionuclides
    gamma-ray spectrometry
    52Mn
    Opis:
    Cosmogenic radionuclides were measured in two specimens of the Sołtmany chondrite (L6) that fell on April 30, 2011. The first fragment (154.9 g) was measured 12 days after the fall and the second piece (120 g), 53 days after the fall. Both fragments were measured by means of non-destructive gamma ray spectroscopy. The first specimen was examined with an ultra-low background high purity germanium (HPGe) detector in a deep underground laboratory. A standard low-background HPGe detector was used to examine the second fragment in a ground level laboratory. Twelve cosmogenic nuclides were detected in the activity range of 0.030 m・Bq g–1 until 1.5 m・Bq g–1 Their activities place constraints on the exposure history of the meteorite and reflect the effect of solar modulation of galactic cosmic rays during the solar maximum. On the activities of expected radionuclides 60 Co (< 0.0075 m・Bq g–1) and 44 Ti (< 0.023 m・Bq g–1) only upper limits could be given. Sołtmany is part of a group of only 14 meteorites where 52 Mn (5.591 d half life) could be determined.
    Źródło:
    Meteorites; 2012, 2, No. 1-2; 45-51
    2299-0313
    2299-1220
    Pojawia się w:
    Meteorites
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermophysical properties of the Sołtmany meteorite
    Autorzy:
    Szurgot, M.
    Wach, R. A.
    Przylibski, T.A.
    Powiązania:
    https://bibliotekanauki.pl/articles/411496.pdf
    Data publikacji:
    2012
    Wydawca:
    Polskie Towarzystwo Meteorytowe
    Tematy:
    chondrite
    differential scanning calorimetry (DSC)
    specific heat capacity
    thermal capacity
    thermal diffusivity
    thermal conductivity
    Opis:
    Bulk density, porosity and thermophysical properties of the Sołtmany meteorite have been determined. The mean bulk density of the meteorite is 3.475‧103kg/m3, mean bulk density of the crust is 4.3‧103 kg/m3, grain density 3.71‧103 kg/m3, and porosity 6.4 ±} 0.4%. Mean specific heat capacity determined by DSC in temperature range between 223 and 823 K increases from 595 to 1046 J/(kg‧K), and is equal to 728 J/(kg‧K) at room temperature. Specific heat capacity of various samples is in the range 705–769 J/(kg‧K) at room temperature. Thermal capacity of Sołtmany chondrite is equal to 2.53‧106 J/(m3‧K), thermal diffusivity (1.5–1.8)‧10-6 m2/s, and thermal conductivity 3.9–4.5 W‧m–-1‧K-1at room temperature. Differential scanning calorimetry revealed two reversible phase transitions in the Sołtmany’s troilite: α/β transition at 423 K, and β/γ transition at 596.6 K.
    Źródło:
    Meteorites; 2012, 2, No. 1-2; 53-65
    2299-0313
    2299-1220
    Pojawia się w:
    Meteorites
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Chemical footprint of the solvent soluble extraterrestrial organic matter occluded in Sołtmany ordinary chondrite
    Autorzy:
    Schmitt-Kopplin, P.
    Harir, M.
    Kanawati, B.
    Tziozis, D.
    Hertkorn, N.
    Gabelica, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/411511.pdf
    Data publikacji:
    2012
    Wydawca:
    Polskie Towarzystwo Meteorytowe
    Tematy:
    ordinary chondrite
    extraterrestrial organic matter
    carbon
    nitrogen
    sulphur
    meteorite
    Sołtmany
    nuclear magnetic
    resonance spectroscopy (NMR)
    Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS)
    Opis:
    By characterizing organic molecules of extra-terrestrial origin included in the Sołtmany meteorite, we also present the first results of the non-targeted chemical analysis of the methanol soluble organic matter present in an L6 ordinary chondrite. The structural characterization by means of ultrahigh resolution Fourier transform ion cyclotron mass spectrometry (FT-ICR-MS) with electrospray ionization (ESI) in negative and positive modes demonstrated an unexpected and astonishing chemical diversity with several thousand mass peaks that could be converted into C, H, N, O, S, and P elemental compositions. Molecular signatures were typically those of considerably oxygenated CHO and CHOS molecular series of primarily aliphatic character. 1H nuclear magnetic resonance (NMR) spectroscopy confirmed the prevalent existence of pure and functionalized aliphatic spin systems of intermediate chain length (C3-4 units), oxygenated aliphatics and a considerable diversity of oxygenated aromatics in the proton-based abundance ratio near 24 : 2 : 1. Although only residual organic matter allegedly survives in highly thermally altered L6 chondrites, the physical protection of organic matter in microcavities and traps between mineral surfaces might have supported and governed the chemistry with an apparent recalcitrance of extraterrestrial organic matter (EOM). Future studies of the organic matter in ordinary chondrites and its composition and structure in various regimes of (e.g.) temperature, radiation, pressure, and water content could shed light on these meteorites’ formation and evolution.
    Źródło:
    Meteorites; 2012, 2, No. 1-2; 79-92
    2299-0313
    2299-1220
    Pojawia się w:
    Meteorites
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

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