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Mössbauerowskie badania meteorytu Kuźnica

100%

Jakubowska M., Woźniak M., Bogusz P., Karwowski Ł., Gałazka-Friedman J., Duda P.

Acta Societatis Metheoriticae Polonorum

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2021

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vol. 12

31-40

EN

Kuźnica meteorite was found in summer 2008 by an inhabitant of Częstochowa in the village of Kuźnica (Poland, voivodeship: Łódź, county: Pajęczano) in Poland. The finder, who is a passionate and collector of interesting stones, shared his find with the world only after a few years in the autumn of 2018. The found meteorite with a mass of 2.14 kg is an ordinary chondrite type H5. The degree of weathering on the surface is W2, inside W1. Currently, the meteorite is represented by 3 parts and two thin plates. The main mass is 2.037 kg, fragments are 13.7 g and 5.81 g. The found object was officially classified as a meteorite on 22th of November 2020. In this paper, we present the results of the Kuźnica meteorite measurements obtained by using the Mössbauer spectroscopy method. Mössbauer measurements of Kuźnica were performed at room temperature. The experimental spectrum was elaborated with “Recoil” program. Nine mineralogical phases were identified in the obtained Mössbauer spectrum: two doublets associated with olivine, two doublets associated with pyroxene, sextet associated with troilite, sextet associated with metallic phase identified as kamacite, doublet associated with iron hydroxides and two sextets associated with oxyhydroxides. The presence of a metallic phase or troilite in the test sample is convincing evidence of its extraterrestrial origin. These are mineralogical phases that can only arise in space conditions. Mössbauer spectroscopy allows for unambiguous identification of these mineralogical phases. In the standard 4M method, we use four basic phases to determine the type of ordinary chondrite: olivine, pyroxene, troilite and metallic phase, and we choose specimens in which the content of weathered phases does not exceed 7%. The Kuźnica meteorite is heavily weathered. The content of weathered phases is as much as 36.4%. Secondary minerals are a breakdown product of the metallic phase and to a lesser extent of the sulphide phase. Due to the strong weathering of the Kuźnica meteorite, we can modify the 4M method using only two basic phases: olivine and pyroxene. The analysis of the location of the Kuźnica meteorite on the figure of pyroxene vs. olivine dependence shows that it is ordinary chondrite type H. In this paper, the influence of the loss of the metallic and sulphide phases on the position of the Kuźnica meteorite on the figure of pyroxene/olivine vs. (pyroxene+metallic phase/(olivine+troilite)) was also checked. Weathering processes significantly transform many minerals. The resulting compounds often have parameters difficult to identify. However, difficulties in identifying secondary phases and their origins should not prevent an attempt to determine the type of meteorites using the 4M method.

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Metoda 4M – nowe zastosowanie spektroskopii mössbauerowskiej w klasyfikacji zrównoważonych chondrytów zwyczajnych

72%

Woźniak M., Karwowski Ł., Gałązka-Friedman J., Duda P., Jakubowska M., Bogusz P.

Acta Societatis Metheoriticae Polonorum

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2020

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vol. 11

125-140

EN

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.

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Od Baszkówki do Kuźnicy – 27 lat badań mössbauerowskich meteorytów w Polsce

72%

Gałązka-Friedman J., Woźniak M.

Acta Societatis Metheoriticae Polonorum

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2023

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vol. 14

31-55

EN

The history, how the Mössbauer studies of meteorites began in Poland, was already described in our “Meteorites Odyssey… 20 years have passed”. One late afternoon (it was probably Spring 1995) I [Jolanta Gałązka-Friedman] was sitting in the Nonna Bakun’s office (at Banacha street) and we were talking about planet Mars. Suddenly Mr. Marian Stępniewski jumped to our room saying: We have a new Polish meteorite. It is called Baszkówka. Do you have any suggestion, how could we study this meteorite? Mössbauer spectroscopy – we both answered at the same time. And this is how it started, and it has been continued for the next quarter of a century. The first results of the Mössbauer studies of the Baszkówka meteorite were presented at the ISIAME conference in Johannesburg in 1996. In this paper we present the most important problems related to meteorites, which were investigated by us using Mössbauer spectroscopy. We will, however, show almost no formulas. We will try to explain everything by a method based on plots of Mössbauer spectra. We will try not to boast too much regarding our successes, but to explain also the problems that we were not able to resolve. While investigating the Baszkówka meteorite, we got most fascinated by troilite. We noticed that most of the laboratories determined the Mössbauer parameters of troilite incorrectly. They did not take into account the so-called theta angle, the value of which depends strongly on the number of vacancies and various additives. We thought that the theta angle may show us the parent body of the investigated meteorite. Unfortunately, this hypothesis turned up to be too difficult to defend. Then we studied Morasko meteorite and we discovered, by the comparison with Baszkówka meteorite Mössbauer spectra, and determined – up to now – not identified mineral phases present also in Morasko, such as pyrrhotite, daubréelite, taenite, tetrataenite, antitaenite and cohenite. In 2019 we published in MAPS a paper titled “Application of Mössbauer spectroscopy, multidimensional discriminant analysis and Mahalanobis distance for classification of equilibrated ordinary chondrites” (4M method), in which a new objective method for classification of ordinary chondrites is based on the knowledge of the Mössbauer spectra of the 4 main mineral phases present in the ordinary chondrites of H, L and LL type. Now we are working on the refinement of the 4M method enlarging our collaborative team by various foreign laboratories.

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Odróżnianie próbek prawdziwych meteorytów od kamiennych próbek meteorytopodobnych – ważna rola spektroskopii mössbauerowskiej

72%

Bogusz P., Gałązka-Friedman J., Brzózka K., Jakubowska M., Woźniak M., Karwowski Ł., Duda P.

Acta Societatis Metheoriticae Polonorum

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2022

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vol. 13

27-36

EN

Four stony pieces were delivered to our laboratory for checking if they are fragments of meteorites: first sample (sample No. 1) was a fragment of a rock that fell near Leoncin in Poland, second sample (sample No. 2) was a fragment of a rock found also in Poland in the vicinity of Pultusk, third sample (sample No. 3) was a meteorite specimen bought on the meteorite exchange and fourth sample (sample No. 4) was a stone object whose decline was observed in Europe. We obtained mössbauer spectra of the delivered samples. The mössbauer spectrum of sample No. 1 is very similar to the spectrum of ordinary chondrite of type LL. Comparison of the mössbauer spectrum of sample No. 2 with mössbauer spectrum of Pułtusk meteorite showed very large differences. In the spectrum of sample No. 3, a clear signal from iron-nickel alloy and troilite can be observed. These observations indicate that it is an object of extraterrestrial origin. Mössbauer spectrum of Sample No. 4 is similar to the spectrum of terrestrial magmatic rocks. Based on these spectrum we cannot clearly determine where the examined object comes from. This work demonstrates the usefulness of Mössbauer spectroscopy in recognizing samples that are fragments of meteorites.

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Mössbauerowskie badania meteorytu Kuźnica

Metoda 4M – nowe zastosowanie spektroskopii mössbauerowskiej w klasyfikacji zrównoważonych chondrytów zwyczajnych

Od Baszkówki do Kuźnicy – 27 lat badań mössbauerowskich meteorytów w Polsce

Odróżnianie próbek prawdziwych meteorytów od kamiennych próbek meteorytopodobnych – ważna rola spektroskopii mössbauerowskiej