Decoupling of Mg from Sr-Nd isotopic compositions in Variscan subduction-related plutonic rocks from the Bohemian Massif: implications for mantle enrichment processes and genesis of orogenic ultrapotassic magmatic rocks

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985530%3A_____%2F22%3A00557724" target="_blank" >RIV/67985530:_____/22:00557724 - isvavai.cz</a>

Alternative codes found

RIV/00025798:_____/22:00000132 RIV/00216208:11310/22:10457211

Result on the web

<a href="https://link.springer.com/article/10.1007/s00531-022-02199-w" target="_blank" >https://link.springer.com/article/10.1007/s00531-022-02199-w</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s00531-022-02199-w" target="_blank" >10.1007/s00531-022-02199-w</a>

Result language

angličtina

Original language name

Decoupling of Mg from Sr-Nd isotopic compositions in Variscan subduction-related plutonic rocks from the Bohemian Massif: implications for mantle enrichment processes and genesis of orogenic ultrapotassic magmatic rocks

Original language description

The Moldanubian Zone of the Bohemian Massif was intruded by three Variscan (c. 354-335 Ma) subduction-related plutonic suites. Their mantle sources evolved from CHUR-like (low-K calc-alkaline suite), through slightly enriched (epsilon(346)(Nd)similar to - 3, high-K calc-alkaline suite-HKCA) to strongly enriched (epsilon(337)(Nd)< - 7.5, (ultra-)potassic suite-UK). This evolution has been previously interpreted in terms of Andean-type subduction passing to deep subduction/relamination of the Saxothuringian continental crust, metasomatizing the mantle source of the HKCA and, more significantly, of the UK suite. This is in accord with the heterogeneity of lithospheric mantle fragments (spinel/garnet peridotites, garnet pyroxenites, eclogites, glimmer-ites...) sampled by the high-grade Moldanubian orogenic root. Newly acquired Mg isotopic compositions (delta Mg-26 = - 0.12 to - 0.53 parts per thousand) vary over similarly broad intervals within each suite. Majority of the most magnesian samples fall within the range of local orogenic mantle peridotites (- 0.33 to - 0.29 parts per thousand) or close to the global mantle average (- 0.25 parts per thousand). This implies that the delta Mg-26 of the progressively metasomatized harzburgitic mantle was mostly buffered by the mantle end-member, while its mantle-incompatible elemental/related isotopic (Sr-Nd-Pb) signal was swamped by the crustally derived contribution. The crustal contaminant, source of the metasomatic fluids, had to be dominated by Mg-poor, felsic metaigneous > > elastic metasedimentary material. Subducted carbonates were of limited importance, as recorded by lowered delta Mg-26 values in several mafic UK samples and in a glimmerite vein cutting the peridotites (- 0.44 parts per thousand). The Mg isotopic variation in less magnesian potassic rock types reflects a complex interplay between source heterogeneity, equilibrium fractionation during fractional crystallization, kinetic fractionation due to chemical diffusion during magma mixing and/or AFC-style contamination by carbonate-derived fluids.

Czech name

—

Czech description

—

Type

J_imp - 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/GA18-24378S" target="_blank" >GA18-24378S: Petrogenesis of (ultra-)potassic magmas in the European Variscides – implications for development of collisional orogens and crustal growth models</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2022

Confidentiality

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

Name of the periodical

International Journal of Earth Sciences

ISSN

1437-3254

e-ISSN

1437-3262

Volume of the periodical

111

Issue of the periodical within the volume

5

Country of publishing house

DE - GERMANY

Number of pages

28

Pages from-to

1491-1518

UT code for WoS article

000801132700001

EID of the result in the Scopus database

2-s2.0-85131093140