Geochemistry of impact glasses and target rocks from the Zhamanshin Impact Structure, Kazakhstan: Implications for mixing of target and impactor matter

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F16%3A00000042" target="_blank" >RIV/00025798:_____/16:00000042 - isvavai.cz</a>

Alternative codes found

RIV/67985831:_____/16:00461314 RIV/00216208:11310/16:10328116

Result on the web

<a href="http://www.sciencedirect.com/science/journal/00167037/190" target="_blank" >http://www.sciencedirect.com/science/journal/00167037/190</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.gca.2016.06.031" target="_blank" >10.1016/j.gca.2016.06.031</a>

Result language

angličtina

Original language name

Geochemistry of impact glasses and target rocks from the Zhamanshin Impact Structure, Kazakhstan: Implications for mixing of target and impactor matter

Original language description

Internal structure and element chemistry including contents of highly siderophile elements (HSE) and Os isotope ratios have been studied in target rocks and impact glasses of the Zhamanshin impact. They can be subdivided into acidic types (irghizites; 69-76 wt.% SiO2), basic splashforms (53-56 wt.% SiO2), and highly inhomogeneous composites. A comparison with the target rocks shows that zhamanshinites and basic splash-forms have no detectable admixture of the projectile matter. In contrast, irghizites exhibit clear admixture of the projectile, which was incorporated by complex processes accompanied by strong element fractionations. Microscopy confirms that irghizites were formed by coalescence of smaller molten glass droplets sized typically below 1 mm. Irghizites exhibit significant enrichments in Ni, Co and Cr, whose concentrations are locally enriched in the rims of the original small droplets. A portion of these elements and also part of Fe and Mn and other elements were derived from the impactor, most likely a Ni-rich carbonaceous chondrite. The contents of HSE are low and strongly fractionated, with moderate depletions of Pt and Pd and strong depletions of other HSE with respect to chondritic element ratios. Osmium shows the strongest depletion, likely related to the presence of oxygen in the post-impact atmosphere causing strong Os loss through volatilization. The observed structural and microchemical features of irghizites are interpreted to reflect variable proportions of the uppermost target sediments and the projectile matter, with HSE element ratios influenced by evaporation and condensation processes, and differences in volatility of individual HSE elements and/or their compounds. Two possible pathways of incorporation of the projectile matter into the irghizites include either re-condensation of evaporated projectile matter on the surface of glass droplets, or incorporation of less chemically fractionated microparticles dispersed by the explosion.

Czech name

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Czech description

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Type

J_x - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)

CEP classification

DD - Geochemistry

OECD FORD branch

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Project

<a href="/en/project/GA13-22351S" target="_blank" >GA13-22351S: Combined use of novel and traditional stable isotope systems in identifying source components and processes of moldavite formation</a><br>

Continuities

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

Publication year

2016

Confidentiality

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

Name of the periodical

Geochimica et Cosmochimica Acta

ISSN

0016-7037

e-ISSN

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Volume of the periodical

190

Issue of the periodical within the volume

1 October

Country of publishing house

GB - UNITED KINGDOM

Number of pages

26

Pages from-to

239-264

UT code for WoS article

000388802600014

EID of the result in the Scopus database

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