A new discovery of parautochthonous moldavites in southwestern Poland, Central Europe

Brachaniec, Tomasz; Szopa, Krzysztof; Karwowski, Łukasz

doi:10.1111/maps.12504

Cited by 10 publications

(28 citation statements)

References 9 publications

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“…Higher temperature caused a lower abundance of lechatelierite in the Czech and German moldavites (Barnes 1969;Lange 1995). Lechatelierite in moldavites is represented by almost pure silica, consistent with previous studies by Knobloch (1997) and Brachaniec et al (2015). Other mineral inclusions are not present in the samples.…”

Section: Bubbles and Lechatelieritesupporting

confidence: 80%

“…Investigated tektites from two sections near Gozdnica are similar in size to those found in 2014. In contrast, much smaller specimens (0.003-0.15 g) were noted in the North Stanisław and Mielęcin pits (Brachaniec et al 2014(Brachaniec et al , 2015. Additionally, the degree of corrosion is similar.…”

Section: Origin Of the Polish Moldavitesmentioning

confidence: 88%

“…EMP data show that the new Pol- See Table 1 for characteristics set. Scale bars are 5 mm ish moldavites are characterized by SiO 2 content ranging from 77.34 to 78.46 wt% which is slightly higher than moldavites from other Polish sections (Brachaniec et al 2015). …”

Section: Resultsmentioning

confidence: 99%

“…According to Brachaniec et al (2014Brachaniec et al ( , 2015 Polish moldavites are parautochthonous. They were found in fluvial sediments, c. 10 Ma in age (Szynkiewicz 2011), whereas the Ries event is dated as c. 14.8 Ma (Buchner et al 2013).…”

Section: Origin Of the Polish Moldavitesmentioning

confidence: 99%

“…According to Artemieva et al (2002) the total mass of created moldavites might be up to 10 10 kg. Brachaniec et al (2014Brachaniec et al ( , 2015 described a new moldavite distribution area in SW Poland. In this paper, based on new finds, their size, shape and chemical features are presented and discussed.…”

Section: Introductionmentioning

confidence: 99%

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New moldavites from SW Poland

Brachaniec¹,

Szopa²,

Karwowski³

2016

Acta Geologica Polonica

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Large impact craters are relatively rare in geological record on the Earth. All over the world only 164 crater structures are above 1 km in diameter and only 40 with with more than 20 km in diameter (Earth Impact Database). The most notable features of such big impacts are significant pressure and temperature caused by extraterrestrial body fall. In some cases, impact may lead to glass production, which is named tektite. The distribution and chemical features of impact glasses are the most diagnostic features of the cosmic body impacts. Tektites are distal ejecta type deposits, next to three other impact melt products (Osinski 2003): (1) crystalline melt bodies in the impact structure, (2) glassy clasts in melt-bearing breccias or suevite, and (3) injection dykes in the crater. These different types of glasses form during the shock melting phase of target. Impact melt glasses resemble a terrestrial volcanic glass in appearance. There are three properties, which can be used to distinguish between the impact and terrestrial types of glasses: (1) the impact glass has a chemical composition of one lithology or mixture of different rock types that are present in the source basement (Dence 1971), (2) it is characterized by the presence of lechatelierite (Stöf-fler 1984), and (3) it has inclusions of shocked minerals (Engelhardt 1972). Characteristic shapes of tektites result from three stages of processes (Baker 1963): (1) the cooling of molten terrestrial material, (2) the flight of tektites through the atmosphere (however this stage did not occur in most of the tektites) and (3) emplacement on Earth's surface, when geochemical processes, like redeposition or weathering, finally influence the morphology of tektites.Up Będzińska Str. 60, krzysztof.szopa@us.edu.pl, lukasz.karwowski@us.edu.pl. ABSTRACT:Brachaniec, T., Szopa, K. and Karwowski, Ł. 2016. New moldavites from SW Poland. Acta Geologica Polonica, 66 (1), 99-105.Warszawa.Four newly discovered moldavites from the East and West Gozdnica pits, SW Poland, are characterized. All specimens, including other four, reported earlier, are from Upper Miocene fluvial sediments of the Gozdnica Formation. Their weight varies between 0.529 and 1.196 g. The moldavites are bottle green in colour and have bubbles and inclusions of lechatelierite. Low degree of corrosion suggests short river transport, apparently eastward from Lusatia.

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Section: Bubbles and Lechatelieritesupporting

confidence: 80%

Section: Origin Of the Polish Moldavitesmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Section: Origin Of the Polish Moldavitesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New moldavites from SW Poland

Brachaniec¹,

Szopa²,

Karwowski³

2016

Acta Geologica Polonica

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Cathodoluminescence of moldavites

Fritzke

Götze

Lange

2017

Meteorit & Planetary Scien

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A systematic study of a large set of moldavites and the application of cathodoluminescence (CL)‐spectroscopy with a detailed discussion of spectral features is presented. Optical CL microscopy and spectroscopy (OM‐CL) were performed on 57 moldavite samples from different substrewn‐fields in Germany and the Czech Republic. The extracted CL data were supported by SEM‐EDX analysis. In general, two different kinds of CL colors can be distinguished: different shades of green in the matrix of the tektite glasses and a variation of blue color for lechatelierite inclusions (a pure silica‐glass phase). Spectral analysis of these colors shows three CL emission bands for green and five bands for blue c. Most CL activators are structural defects of the local glass network, influenced by the crystal field. The visible green CL emission is caused by defects related to strong local disorder as well as Al‐O−‐Al defects. The blue CL emission is activated by different types of lattice defects such as nonbridging oxygen‐hole center (NBOHC), self‐trapped excitons (STE), and oxygen deficiency centers (ODC). Intensity variations of the CL emissions were observed for samples from the different localities, but there is no direct correlation between substrewn‐fields and CL characteristics. Nevertheless, CL microscopy is a powerful tool for the high‐contrast visualization of internal textures such as streaks and lechatelierite in the tektite matrix due to the luminescence properties of the defect structures in the glassy network.

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An experimental model for the tektite fluvial transport based on the most distal Polish moldavite occurrences

Brachaniec

2017

Meteorit & Planetary Scien

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Reworking and redeposition of tektites is a highly complex and multistage geological process including many factors. A tumbling experiment was therefore undertaken with the aim of estimating a distance of transport that such moldavites can withstand. Though the experiment probably did not accurately mimic natural conditions, our results proved that moldavites can withstand considerable transport only over a distance of a few kilometers. Observed abrasion of tektites was significant in the early stage of experimental transport; the rate of abrasion decreased correlatively with increasing distance of transport as usual. Overall, given the results obtained from this experimental study and their state of preservation described in the literature, it is very likely that Polish tektites were reworked and redeposited by rivers from the Sudetes Mountains. Based on the paleoreconstruction of river flows, it can be assumed that the Polish tektites originated from two independent sediment supply areas.

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A new discovery of parautochthonous moldavites in southwestern Poland, Central Europe

Cited by 10 publications

References 9 publications

New moldavites from SW Poland

New moldavites from SW Poland

Cathodoluminescence of moldavites

An experimental model for the tektite fluvial transport based on the most distal Polish moldavite occurrences

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