Chemistry of Tertiary sediments in the surroundings of the Ries impact structure and moldavite formation revisited

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F16%3A00000022" target="_blank" >RIV/00025798:_____/16:00000022 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/67985831:_____/16:00458591 RIV/61389005:_____/16:00458591 RIV/00216208:11310/16:10328901

Výsledek na webu

<a href="http://www.sciencedirect.com/science/journal/00167037" target="_blank" >http://www.sciencedirect.com/science/journal/00167037</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.gca.2016.01.025" target="_blank" >10.1016/j.gca.2016.01.025</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Chemistry of Tertiary sediments in the surroundings of the Ries impact structure and moldavite formation revisited

Popis výsledku v původním jazyce

Moldavites have been linked with the Ries impact in Germany. They are supposed to be derived mainly from the near-surface sediments of the Upper Freshwater Molasse (OSM) that probably covered the target area before the impact. Comparison of the chemical composition of moldavites with that of inferred source materials requires recalculation of the composition of sediments to their volatile-free residuum. This recalculation reflects almost complete loss of volatiles from the target materials during their transformation to moldavites. Strong depletions of many elements in moldavites relative to the source sediments (e.g., Mo, Cu, Ag, Sb, As, Fe) contrast with enrichments of some elements in moldavites (e.g., Cs, Ba, K, Rb). This can be solved using either involvement of a specific component, or by considering elemental fractionation during tektite formation. The proposed model of moldavite formation combines both approaches and is based on several steps: (i) the parent mixture (dominated by OSM sediments) contained also a minor admixture of organic matter and soils; (ii) the most energetic part of the ejected matter was converted to vapor (plasma) and another part produced melt directly upon decompression; (iii) following further adiabatic decompression, the expanding vapor phase disintegrated the melt into small melt droplets and some elements were partially lost from the melt because of their volatility, or because of the volatility of their compounds, (e.g. carbonyls of Fe and other transition metals); (iv) large positively charged ions (Cs+, Ba2+, K+, Rb+) from the plasma were enriched in late-stage condensation spherules or condensed directly onto negatively charged melt droplets; (v) melt droplets coalesced into larger tektite bodies. Steps (iii) to (v) may have overlapped in time.

Název v anglickém jazyce

Chemistry of Tertiary sediments in the surroundings of the Ries impact structure and moldavite formation revisited

Popis výsledku anglicky

Moldavites have been linked with the Ries impact in Germany. They are supposed to be derived mainly from the near-surface sediments of the Upper Freshwater Molasse (OSM) that probably covered the target area before the impact. Comparison of the chemical composition of moldavites with that of inferred source materials requires recalculation of the composition of sediments to their volatile-free residuum. This recalculation reflects almost complete loss of volatiles from the target materials during their transformation to moldavites. Strong depletions of many elements in moldavites relative to the source sediments (e.g., Mo, Cu, Ag, Sb, As, Fe) contrast with enrichments of some elements in moldavites (e.g., Cs, Ba, K, Rb). This can be solved using either involvement of a specific component, or by considering elemental fractionation during tektite formation. The proposed model of moldavite formation combines both approaches and is based on several steps: (i) the parent mixture (dominated by OSM sediments) contained also a minor admixture of organic matter and soils; (ii) the most energetic part of the ejected matter was converted to vapor (plasma) and another part produced melt directly upon decompression; (iii) following further adiabatic decompression, the expanding vapor phase disintegrated the melt into small melt droplets and some elements were partially lost from the melt because of their volatility, or because of the volatility of their compounds, (e.g. carbonyls of Fe and other transition metals); (iv) large positively charged ions (Cs+, Ba2+, K+, Rb+) from the plasma were enriched in late-stage condensation spherules or condensed directly onto negatively charged melt droplets; (v) melt droplets coalesced into larger tektite bodies. Steps (iii) to (v) may have overlapped in time.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

DD - Geochemie

OECD FORD obor

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Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Geochimica et Cosmochimica Acta

ISSN

0016-7037

e-ISSN

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Svazek periodika

179

Číslo periodika v rámci svazku

April

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

25

Strana od-do

287-311

Kód UT WoS článku

000372565800016

EID výsledku v databázi Scopus

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