Mantle Zn Isotopic Heterogeneity Caused by Melt‐Rock Reaction: Evidence From Fe‐Rich Peridotites and Pyroxenites From the Bohemian Massif, Central Europe

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F19%3A00505049" target="_blank" >RIV/67985831:_____/19:00505049 - isvavai.cz</a>

Výsledek na webu

<a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JB017125" target="_blank" >https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JB017125</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1029/2018JB017125" target="_blank" >10.1029/2018JB017125</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Mantle Zn Isotopic Heterogeneity Caused by Melt‐Rock Reaction: Evidence From Fe‐Rich Peridotites and Pyroxenites From the Bohemian Massif, Central Europe

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

Mantle Zn Isotopic Heterogeneity Caused by Melt‐Rock Reaction: Evidence From Fe‐Rich Peridotites and Pyroxenites From the Bohemian Massif, Central Europe

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

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

Název periodika

Journal of Geophysical Research: Solid Earth

ISSN

2169-9313

e-ISSN

—

Svazek periodika

124

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

17

Strana od-do

3588-3604

Kód UT WoS článku

000468912000020

EID výsledku v databázi Scopus

2-s2.0-85065211757