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Implications for behavior of volatile elements during impacts—Zinc and copper systematics in sediments from the Ries impact structure and central European tektites
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SYSNO ASEP 0479288 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Implications for behavior of volatile elements during impacts—Zinc and copper systematics in sediments from the Ries impact structure and central European tektites Author(s) Rodovská, Z. (CZ)
Magna, T. (CZ)
Žák, Karel (GLU-S) SAI, RID, ORCID
Kato, C. (FR)
Savage, P. S. (FR)
Moynier, F. (FR)
Skála, Roman (GLU-S) RID, SAI, ORCID
Ježek, J. (CZ)Source Title Meteoritics & Planetary Science. - : Wiley - ISSN 1086-9379
Roč. 52, č. 10 (2017), s. 2178-2192Number of pages 15 s. Publication form Print - P Language eng - English Country US - United States Keywords moldavites ; tektites ; Ries impact structure Subject RIV DB - Geology ; Mineralogy OECD category Geology R&D Projects GA13-22351S GA ČR - Czech Science Foundation (CSF) Institutional support GLU-S - RVO:67985831 UT WOS 000412173600007 EID SCOPUS 85026364214 DOI 10.1111/maps.12922 Annotation Moldavites are tektites genetically related to the Ries impact structure, located in Central Europe, but the source materials and the processes related to the chemical fractionation of moldavites are not fully constrained. To further understand moldavite genesis, the Cu and Zn abundances and isotope compositions were measured in a suite of tektites from four different substrewn fields (South Bohemia, Moravia, Cheb Basin, Lusatia) and chemically diverse sediments from the surroundings of the Ries impact structure. Moldavites are slightly depleted in Zn (ca 10–20%) and distinctly depleted in Cu (>90%) relative to supposed sedimentary precursors. Moreover, the moldavites show a wide range in .delta.66Zn values between 1.7 and 3.7‰ (relative to JMC 3-0749 Lyon) and .delta.65Cu values between 1.6 and 12.5‰ (relative to NIST SRM 976) and are thus enriched in heavy isotopes relative to their possible parent sedimentary sources (.delta.66Zn = −0.07 to +0.64‰, .delta.65Cu = −0.4 to +0.7‰). In particular, the Cheb Basin moldavites show some of the highest .delta.65Cu values (up to 12.5‰) ever observed in natural samples. The relative magnitude of isotope fractionation for Cu and Zn seen here is opposite to oxygen-poor environments such as the Moon where Zn is significantly more isotopically fractionated than Cu. One possibility is that monovalent Cu diffuses faster than divalent Zn in the reduced melt and diffusion will not affect the extent of Zn isotope fractionation. These observations imply that the capability of forming a redox environment may aid in volatilizing some elements, accompanied by isotope fractionation, during the impact process. The greater extent of elemental depletion, coupled with isotope fractionation of more refractory Cu relative to Zn, may also hinge on the presence of carbonyl species of transition metals and electromagnetic charge, which could exist in the impact-induced high-velocity jet of vapor and melts. Workplace Institute of Geology Contact Jana Popelková, popelkova@gli.cas.cz, Sabina Janíčková, Tel.: 233 087 272 Year of Publishing 2018
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