Carbonate-rich dyke in Roztoky Intrusive Complex – an evidence for carbonatite magmatism in the Eger Rift?

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F17%3A00000085" target="_blank" >RIV/00025798:_____/17:00000085 - isvavai.cz</a>
Result on the web
<a href="http://www.jgeosci.org/content/jgeosci.238_rapprich.pdf" target="_blank" >http://www.jgeosci.org/content/jgeosci.238_rapprich.pdf</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.3190/jgeosci.238" target="_blank" >10.3190/jgeosci.238</a>

Result language
angličtina
Original language name
Carbonate-rich dyke in Roztoky Intrusive Complex – an evidence for carbonatite magmatism in the Eger Rift?
Original language description
The possible presence of carbonatites in the Eger Rift (NW Bohemian Massif, Czech Republic) has been debated for several decades without any apparent resolution. Here, we document an almost 2 m thick dyke of a silicocarbonatite (23 wt. % SiO2, 27 wt. % CO2) in the R2 (Roztoky nad Labem) drilling at the depth of 152.9–154.8 m. Despite the fact that the silicocarbonatite is associated with alkaline intrusive complex, its content of alkalis is rather low (Na2O + K2O = 2.5 wt. %), as are REE (ΣREE = 82.6 ppm). The stable isotope signature (δ18O = 7.43 ‰, δ13C = −2.46 ‰) of this rock is distinct from surrounding sedimentary rocks, while it can be compared with C–O isotope systematics of some carbonatites in the world which probably sourced carbonates from older subduction events. The Sr–Nd isotope composition (87Sr/86Sr30 ~ 0.7062; 143Nd/144Nd30 ~ 0.51205) points to an enriched reservoir without known counterparts among alkaline rocks from the Eger Rift, perhaps a lithospheric mantle modified in course of the Variscan subduction. The position of the R2 silicocarbonatite in the Sr–Nd space may indicate a continuum of enriched radiogenic isotope systematics in worldwide carbonatite occurrences.
Czech name
—
Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10505 - Geology

Project
<a href="/en/project/GA15-08583S" target="_blank" >GA15-08583S: Role of carbonatites for Zr–Hf–Nb–Ta and highly siderophile element budgets in the Earth’s mantle – combined stable–radiogenic isotope approach</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2017
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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