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Mantle Zn Isotopic Heterogeneity Caused by Melt‐Rock Reaction: Evidence From Fe‐Rich Peridotites and Pyroxenites From the Bohemian Massif, Central Europe
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SYSNO ASEP 0505049 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Mantle Zn Isotopic Heterogeneity Caused by Melt‐Rock Reaction: Evidence From Fe‐Rich Peridotites and Pyroxenites From the Bohemian Massif, Central Europe Tvůrce(i) Huang, J. (CN)
Ackerman, Lukáš (GLU-S) RID, SAI, ORCID
Zhang, X-CH. (CN)Zdroj.dok. Journal of Geophysical Research-Solid Earth. - : Wiley - ISSN 2169-9313
Roč. 124, č. 4 (2019), s. 3588-3604Poč.str. 17 s. Forma vydání Tištěná - P Jazyk dok. eng - angličtina Země vyd. US - Spojené státy americké Klíč. slova zinc isotopes ; peridotite ; pyroxenite ; melt‐rock reaction ; mantle heterogeneity Vědní obor RIV DB - Geologie a mineralogie Obor OECD Geology Způsob publikování Omezený přístup Institucionální podpora GLU-S - RVO:67985831 UT WOS 000468912000020 EID SCOPUS 85065211757 DOI 10.1029/2018JB017125 Anotace To investigate the effect of melt‐rock reaction on Zn isotope fractionation and mantle Zn isotopic heterogeneity, we analyzed Zn isotopic compositions of peridotites, pyroxenites, and mineral separates from the Bohemian Massif, Central Europe. The Mg‐lherzolites (Mg# = 90.9 to 89.1, FeOT = 7.9 to 9.0 wt %) are melting residues with only moderate metasomatism and have δ66Zn from 0.11 to 0.20‰. In contrast, the Fe‐rich peridotites (Mg# = 88.2 to 80.3, FeOT = 10.0 to 14.5 wt %) and pyroxenites have larger ranges of δ66Zn from 0.11 to 0.31‰ and −0.33 to 0.42‰, respectively. Large disequilibrium intermineral Zn isotope fractionation occurs in the Fe‐rich peridotites and pyroxenites with Δ66ZnOpx‐Ol = −0.50‰, Δ66ZnGrt‐Ol = −0.55 to −0.39‰, Δ66ZnGrt‐Opx = −0.28 to −0.05‰, and Δ66ZnGrt‐Cpx = −0.50 to 0.12‰. Combined with their low SiO2 contents and radiogenic Sr‐Nd‐Os isotopic compositions, the high δ66Zn of the Fe‐rich peridotites is attributed to reaction between Mg‐lherzolites and percolating SiO2‐undersaturated basaltic melts that incorporated isotopically heavy crustal components. Crystallization of the isotopically heavy percolating melts migrating through the lithospheric mantle yield the high‐δ66Zn pyroxenites. The low δ66Zn of the pyroxenites and large intermineral Zn isotopic disequilibrium may result from kinetic Zn isotope fractionation during melt‐rock reaction. Collectively, these observations indicate that melt‐rock reaction can cause intermineral Zn isotopic disequilibrium and significant Zn isotopic heterogeneity in the mantle. This study thus highlights the potential use of Zn isotopes to trace melt‐rock reaction events in the mantle. Pracoviště Geologický ústav Kontakt Jana Popelková, popelkova@gli.cas.cz, Sabina Janíčková, Tel.: 233 087 272 Rok sběru 2020 Elektronická adresa https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JB017125
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