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1
Content available 30 lat mössbauerowskich badań meteorytów w Polsce
PL
Spektroskopia mössbauerowska57 Fe jest jedną z najczęściej stosowanych metod badania meteorytów. Początek badań mössbauerowskich w Polsce związany jest z meteorytem Baszkówka, który spadł 25.08.1994 w okolicach Warszawy. W artykule przedstawione są niektóre wyniki 30-letnich mössbauerowskich badań meteorytów, otrzymane przez polski zespół badawczy. Do najważniejszych osiągnięć naszej grupy należy opracowanie metody klasyfikacji chondrytów zwyczajnych, które stanowią 87% meteorytów znajdowanych na powierzchni Ziemi. Metoda ta nazwana przez nas metodą 4M (od angielskojęzycznych terminów meteorites, Mössbauer spectroscopy, multidimensional discriminant analysis, Mahalanobis distance) jest metodą ilościową, wykorzystującą pewne systematyczności w mössbauerowskich widmach chondrytów zwyczajnych.1 Podstawowym elementem metody 4M jest baza danych, która w tej chwili składa się z wyników mössbauerowskich pomiarów 87 próbek meteorytów. W artykule omówione są również nowe fazy mineralne zidentyfikowane w meteorycie Morasko. Podano przykłady zastosowania spektroskopii mössbauerowskiej do odróżniania próbek meteorytopodobnych od prawdziwych meteorytów. Omówiliśmy też nasze plany związane z badaniem mechanizmu powstawania chondrytów zwyczajnych oraz z zastosowaniem spektroskopii mössbauerowskiej w przyszłych misjach kosmicznych. Te ostatnie problemy będą rozwiązywane we współpracy z czeską pracownią mössbauerowską Uniwersytetu Palackiego w Ołomuńcu.
EN
57Fe Mössbauer spectroscopy is one of the most commonly used methods for studying meteorites. The beginning of Mössbauer research in Poland is associated with the Baszkówka meteorite, which fell on 25 August 1994 near Warsaw. The article presents some of the results of 30 years of Mössbauer studies of meteorites by the Polish team. One of the most important achievements of our group is the development of a classification method of ordinary chondrites, which constitute 87% of meteorites found on the earth’s surface. This method, which we call the 4M method (meteorites, Mössbauer spectroscopy, multidimensional discriminant analysis, Mahalanobis distance), is a quantitative method that uses certain systematicity in the Mössbauer spectra of ordinary chondrites. The basic element of the 4M method is the database, which currently consists of the results of Mössbauer measurements of 87 meteorite samples. The article also discusses the new mineral phases identified in the Morasko meteorite. Examples of the use of Mössbauer spectroscopy to distinguish meteorite-like samples from real meteorites are given. Our research plans related to the study of the formation mechanism of ordinary chondrites and the use of Mössbauer spectroscopy in future space missions are also discussed. The latter issues will be undertaken in cooperation with the Mössbauer laboratory at Palacký University in Olomouc (Czech Republic).
EN
Extraterrestrial resources should be the basic sources of materials for the development of humankind civilization in space as well as they could replace the Earth’s resources when they would be exhausted. They can be obtained from the planets, their moons or asteroids, primarily NEOs but also from the asteroid belt. This article presents the results of petrographic research on the content of FeNi minerals whose may be a source of iron and nickel, in H type ordinary chondrites: Pułtusk, Cher- gach, Tamdakht, Gao-Guenie andNWA 4555, which parent body is probably the 6Hebe. The results confirm that the volumetric abundance of FeNi minerals in H type chondrites is ca. 8%. Moreover, this study shows the reliability of the reflected-light optical microscopy for determination of ore mineral concentrations in extraterrestrial rocks with weathering grade W0. Taking into account the homogenous spatial distribution of metallic grains (proved by author’s microscopic observations) and knowing the amount of FeNi minerals in rocks with Hchondrite composition, the amount of potential FeNi resources on Hparent bodies can be calculated. It was estimated that the iron resources from Hebe’s FeNi minerals would cover 1.3 million years of terrestrial mining production whereas nickel resources would last for approx. 100 milion years. A small NEO asteroid like (143624) 2003 HM16 (2 km in diameter) has resources comparable with 15 months of mining iron production and over 100 years of nickel production at present rate.
EN
One of the largest observed stone meteorite shower in the history of mankind on Earth took place on Thursday evening on January 30, 1868, about seven o’clock near Pułtusk in Poland. Despite the 150th anniversary of the fall of chondrite officially classified as Pułtusk H5 with a shock stage S3 there is still little published data on the chemical composition of minerals of this chondrite as well as its petrological characteristics in the literature. The authors carried out mineralogical and petrological research that will help a little to fill this gap in knowledge about the Pułtusk chondrite. Meteorite specimens found by Piotr Kuś in 2015 and investigated by the authors are undoubtedly part of the Pułtusk fall of January 30, 1868. They can be classified as ordinary chondrite H5, S2,W2. The authors stated that the studied rock is characterized by a varied shock level -from S1 to S2/3, as well as it contains chondrules of the chromite-plagioclase unequilibrated rock. In the composition of the examined fragment of Pułtusk chondrite, the authors identified silicates: olivine, diopside, bronzite and clinohyperstene, and oligoclase, oxides: chromite (and spinel), sulfides: troilite, FeNi alloy mineral phases: kamacite and taenite, as well as phosphates: merrilite and apatite. The chemical composition of olivine crystals as well as low- and high-Ca pyroxenes crystals and plagioclase crystals (about the composition of oligoclase) confirms that the examined specimen comes from the Pułtusk fall and it is a rock that should be classified as a petrographic type H5.
EN
Shock impact-produced mineral alterations in two thin sections of the recently found Csátalja H4 ordinary chondrite meteorite are compared. Peak positions of Raman and infrared spectra of mineral clasts show peaks shifted in wavenumber relative to unshocked reference minerals, and both peak shifts and FWHM values seem to correlate to each other. In the less shocked thin section (Csátalja-1) a more monomineralic and homogeneous composition indicate shock pressures of <15 GPa, while the more shocked Csátalja-2 indicates shock pressure in the 15–17 GPa range. The highest identified infrared peak position shifts range between –48 and +28 cm–1 with peak broadening between 60–84 cm–1 in the case of the feldspars, which, together with sulphide globules, were produced by the shock itself. Feldspar spectra could be detected only by FTIR spectroscopy, but in most cases (above the S3 shock level) the mixed type of the pyroxene-feldspar spectra (both peaks in the same spectra) is in agreement with the shock-produced secondary feldspars. These grains are located around crystalline borders, and probably formed by selective melting, due to shock annealing. In reconstruction of the shock history, an early fragmentation by a lower shock effect and a later increased shock level-related vein and melt pocket formation occurred, with subsequent shock annealing; temporal reconstruction of the shock event is possible only in part. The joint usage of Raman and infrared spectroscopy provided useful insights into the shock-produced changes and their spatial inhomogeneity, while shocked feldspar could be better detected by infrared than by the Raman method.
5
Content available Sołtmany meteorite
EN
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.
EN
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.
EN
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.
8
Content available Bulk chemical composition of Sołtmany chondrite
EN
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.
9
Content available Shock veins in the Sahara 02500 ordinary chondrite
EN
A specimen of the Sahara 02500 ordinary chondrite contains shock-produced veins consisting of recrystallised fine-grained pyroxenes that include small droplets of Ni-rich metal. Non-melted olivines and pyroxenes show planar deformations filled by shock-melted and -polluted metal and troilite. Shock-melted feldspathic glass is present close to the shock veins. Geothermometric estimations indicate that the meteorite locally experienced moderate shock metamorphism with a minimum local peak temperature above 1400ºC, resulting in partial melting of Ca-poor pyroxene and full melting of feldspars, metal and sulphides. The mineral assemblage in the shock veins suggests a pressure during melt recrystallisation below 10 GPa.
EN
Two ordinary chondrites are compared and classified using transmitted and reflected light microscopy and electron microprobe analyses. Both meteorites were confiscated by the Polish Customs Service at the border with Belarus. The first meteorite (called in this paper Terespol-1) is a L/LL6 chondrite, its classification being supported by the equilibrated compositions of olivine and orthopyroxene and the presence of large recrystallized feldspars (< 150 μm). The specimen examined experienced weak shock metamorphism (S3) and moderate weathering (although metal in the inner part of the meteorite seems to be unaffected by oxidization). The other meteorite (called in this paper Terespol-2) is a LL6 chondrite which experienced weak shock metamorphism (S3) and is unaffected by weathering. The Terespol-2 meteorite shares its classification with the Dhofar 1401 chondrite but the lack of data prevents further correlation. Both meteorites have been correlated with known findings from the Meteoritical Bulletin database and an attempt is made to identify their place of origin (fall event). Results indicate that Terespol-1 is most closely related to the Dhofar 1316 chondrite and we suggest that both meteorites at least came from the same parent body.
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