Ultrapotassic magmatism in the heyday of the Variscan Orogeny: the story of the Třebíč Pluton, the largest durbachitic body in the Bohemian Massif

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F20%3A00000111" target="_blank" >RIV/00025798:_____/20:00000111 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/67985831:_____/20:00525320 RIV/00216208:11310/20:10416439

Výsledek na webu

<a href="https://link.springer.com/article/10.1007/s00531-020-01872-2" target="_blank" >https://link.springer.com/article/10.1007/s00531-020-01872-2</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s00531-020-01872-2" target="_blank" >10.1007/s00531-020-01872-2</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Ultrapotassic magmatism in the heyday of the Variscan Orogeny: the story of the Třebíč Pluton, the largest durbachitic body in the Bohemian Massif

Popis výsledku v původním jazyce

The Trebic Pluton (TP) comprises plutonic rocks of the `durbachite series', i.e., ultrapotassic biotite-amphibole quartz melasyenites-melagranites with conspicuous K-feldspar phenocrysts and abundant mafic enclaves. The TP with its satellite bodies intruded the eastern Moldanubian Zone (orogenic root of the Variscan Bohemian Massif) at c. 338 Ma. Overall, the entire TP durbachite series -(SiO2 = 52-67 wtpercent) remains highly magnesian, reduced, and ( except when strongly contaminated) metaluminous. The durbachitic rocks are markedly enriched in lithophile elements (esp. Cs, Rb, Th, U, K and Pb) and LREE; in contrast, the contents of high-field strength elements (Nb, Ta, and Ti) and Sr are much lower, resulting in conspicuous negative anomalies in Primitive mantle-normalized multielement plots. The proposed petrogenetic model requires re-enrichment of the depleted, harzburgitic lithospheric mantle by deeply subducted crustal material of the Saxothuringian lower plate, directly and/or via (U)HP melt/fluid. This process produced phlogopite-rich metasomes (phlogopite harzburgites and/or glimmerites). The metasomes re-melted soon thereafter by a short thermal pulse caused by slab break-off or decompression melting of rising diapirs of the relatively light metasomatized mantle, yielding primary ultrapotassic melts (87Sr/86Sr337 > 0.712 and similar to Eps337Nd = 7.6). Upon their passage through the Moldanubian upper plate, ultrapotassic primary magmas mixed with felsic anatectic melts (87Sr/86Sr337 < 0.710; similar to Eps337 Nd > - 6.5). K-feldspar-driven fractional crystallization +/- accumulation represented only a late modifying influence. The occurrence of such ultrapotassic enriched/crustally contaminated mantle-derived magmatism complicates any conventional mass-balance assessments of relative roles of crustal recycling vs. growth in hot collisional orogens, e.g., Variscides or Himalayas.

Název v anglickém jazyce

Ultrapotassic magmatism in the heyday of the Variscan Orogeny: the story of the Třebíč Pluton, the largest durbachitic body in the Bohemian Massif

Popis výsledku anglicky

The Trebic Pluton (TP) comprises plutonic rocks of the `durbachite series', i.e., ultrapotassic biotite-amphibole quartz melasyenites-melagranites with conspicuous K-feldspar phenocrysts and abundant mafic enclaves. The TP with its satellite bodies intruded the eastern Moldanubian Zone (orogenic root of the Variscan Bohemian Massif) at c. 338 Ma. Overall, the entire TP durbachite series -(SiO2 = 52-67 wtpercent) remains highly magnesian, reduced, and ( except when strongly contaminated) metaluminous. The durbachitic rocks are markedly enriched in lithophile elements (esp. Cs, Rb, Th, U, K and Pb) and LREE; in contrast, the contents of high-field strength elements (Nb, Ta, and Ti) and Sr are much lower, resulting in conspicuous negative anomalies in Primitive mantle-normalized multielement plots. The proposed petrogenetic model requires re-enrichment of the depleted, harzburgitic lithospheric mantle by deeply subducted crustal material of the Saxothuringian lower plate, directly and/or via (U)HP melt/fluid. This process produced phlogopite-rich metasomes (phlogopite harzburgites and/or glimmerites). The metasomes re-melted soon thereafter by a short thermal pulse caused by slab break-off or decompression melting of rising diapirs of the relatively light metasomatized mantle, yielding primary ultrapotassic melts (87Sr/86Sr337 > 0.712 and similar to Eps337Nd = 7.6). Upon their passage through the Moldanubian upper plate, ultrapotassic primary magmas mixed with felsic anatectic melts (87Sr/86Sr337 < 0.710; similar to Eps337 Nd > - 6.5). K-feldspar-driven fractional crystallization +/- accumulation represented only a late modifying influence. The occurrence of such ultrapotassic enriched/crustally contaminated mantle-derived magmatism complicates any conventional mass-balance assessments of relative roles of crustal recycling vs. growth in hot collisional orogens, e.g., Variscides or Himalayas.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GA18-24378S" target="_blank" >GA18-24378S: Petrogeneze (ultra-)draselných magmat evropských Variscid – implikace pro vývoj kolizních orogenů a modely krustálního růstu</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2020

Kód důvěrnosti údajů

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

Název periodika

International Journal of Earth Sciences

ISSN

1437-3254

e-ISSN

—

Svazek periodika

109

Číslo periodika v rámci svazku

May

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

44

Strana od-do

1767-1810

Kód UT WoS článku

000542409900016

EID výsledku v databázi Scopus

2-s2.0-85085756349