Origin of moldavites

Engelhardt, Wolf von; Luft, E.; Arndt, Jörg; Schock, H. H.; Weiskirchner, W.

doi:10.1016/0016-7037(87)90326-7

Cited by 97 publications

(90 citation statements)

References 49 publications

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“…There is a variety of possibilities: it is well known from studies of the other three strewn fields (e.g., Montanari and Koeberl 2000 and references therein) that tektites are mainly derived from surficial sediments. For example, the Central European tektites (moldavites) were derived from a thin surface veneer of sediments of immediate pre-impact age that are not present anymore in today's Ries crater (e.g., Horn et al 1985;von Engelhardt et al 1987). Our sample suite did not include any upper Eocene sediments that were present on or near the target surface in the Chesapeake Bay area because such rocks are not preserved.…”

Section: Discussionmentioning

confidence: 99%

Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence

Deutsch

Koeberl

2006

Meteoritics &Amp; Planetary Science

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, which is in excellent agreement with previously published data for samples of the NAT strewn field. Target rocks with highly radiogenic Sr isotopic composition, as required for explaining the isotopic characteristics of Deep Sea Drilling Project (DSDP) site 612 tektites, were not among the analyzed sample suite. Based on the new isotope data, we exclude any relation between the NA tektites and the Popigai impact crater, although they have identical ages within 2σ errors. The Chesapeake Bay structure, however, is now clearly constrained as the source crater for the North American tektites, although the present data set obviously does not include all target lithologies that have contributed to the composition of the tektites.

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Section: Discussionmentioning

confidence: 99%

Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence

Deutsch

Koeberl

2006

Meteoritics &Amp; Planetary Science

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“…Therefore the larger 13 isotopic fractionation in Cu than in Zn in tektites is due to the significant difference in their 14 respective chemical diffusivity 15 1 2 Tektites are terrestrial natural glasses of up to a few cm diameter size that are produced during 3 the early phases of a hypervelocity impact of an asteroid or a comet into terrestrial rock (Blum et 4 al., 1992;Glass, 1990;Koeberl, 1986;Koeberl, 1990;Koeberl, 1992). Tektites have been found 5 in only four geographically extended strewn fields (Glass et al, 1991): the North American 6 strewn field of age ~35 Ma (associated with the Chesapeake Bay impact structure, east of the 7 USA (Koeberl et al, 1996;Poag et al, 2004)); the Central European strewn field (associated 8 with the Ries crater in Bavaria, Germany, Engelhardt et al (1987)) of age ~14. 4 Ma, the Ivory 9…”

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confidence: 99%

Isotopic fractionation of Cu in tektites

Moynier¹,

Koeberl

Beck

et al. 2010

Geochimica et Cosmochimica Acta

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≈0). 4The correlation of δ 65 Cu with the abundance of Cu probably reflects that the isotopic 5 fractionation occurred by evaporation during heating. A simple Rayleigh distillation cannot 6 explain the Cu isotopic data and we suggest that the isotopic fractionation is governed by a 7 diffusion-limited regime. Cu (1.99<δ 65 Cu<6.98) is isotopically more fractionated than the more 8 volatile element Zn (δ 66/64 Zn up to 2.49 ‰). This difference of behavior between Cu and Zn is 9 predicted in a diffusion-limited regime where the magnitude of the isotopic fractionation is 10 regulated by the balance between the evaporative flux and the diffusive flux at the diffusion 11 boundary layer. Due to the difference of ionic charge in silicates (Zn 2+ vs Cu + ), Cu has a 12 coefficient of diffusion larger than Zn by at least two orders of magnitude. Therefore the larger 13 isotopic fractionation in Cu than in Zn in tektites is due to the significant difference in their 14 respective chemical diffusivity 15 3

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“…The moldavites are the most acidic group of tektites, with SiO 2 contents c. 80 wt% (Engelhardt et al 1987;Trnka and Houzar 2002). EMPA data show (Table 2) that the investigated moldavites have relatively high content of SiO 2 and low content of Fe.…”

Section: Chemical Compositionmentioning

confidence: 99%

“…In the 1960s, it was confirmed that moldavites are distributed over three specific areas: the Czech Republic (Bohemia, Moravia and near Cheb), Lusatia (SE Germany) and northern Austria (Trnka and Houzar 2002, and references therein). Until now, these tektites have been the subject of numerous geochemical, sedimentological and physical investigations (e.g., Knobloch et al 1981Knobloch et al , 1983Engelhardt et al 1987Engelhardt et al , 2005Koeberl et al 1988;Lange 1995;Meisel et al 1997;Stöffler et al 2002;Skála and Čada 2003;Řanda et al 2008;Buchner and Schmieder 2009;Žák et al 2012;Glass and Simonson 2013). Moldavites source impact structure is the Nördlinger Ries crater in southern Germany.…”

Section: Introductionmentioning

confidence: 99%

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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Origin of moldavites

Cited by 97 publications

References 49 publications

Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence

Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence

Isotopic fractionation of Cu in tektites

New moldavites from SW Poland

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