Origin of the Brunovistulian microcontinent: Geochemical and Sr-Nd-Pb-Hf isotope evidence

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F25%3A00638964" target="_blank" >RIV/67985831:_____/25:00638964 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216224:14310/25:00143284 RIV/00216305:26110/26:0200500

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0301926825002281" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0301926825002281</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.precamres.2025.107902" target="_blank" >10.1016/j.precamres.2025.107902</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Origin of the Brunovistulian microcontinent: Geochemical and Sr-Nd-Pb-Hf isotope evidence

Popis výsledku v původním jazyce

The Brunovistulian microcontinent (BVM) represents the largest (up to 30 000 km2) geological unit of Proterozoic provenance in the eastern part of the Variscan collision zone in Central Europe. We present whole-rock, mineral and Sr–Nd–Pb–Hf isotope compositions of representative samples from exposures and deep boreholes (up to 3 km in depth) situated in the Czech part of the BVM. The oldest rocks are ∼ 740 Ma Tonian basic metavolcanic rocks and associated felsic dykes and metatuffs of the Metavolcanic Zone. Geochemical and isotope characteristics of these felsic rocks confirm that their parent melts were derived from the upper mantle, similar to their metabasite hosts. The Tonian (Pan-African) age of the Metavolcanic Zone and its MORB-like geochemical and isotope signature (87Sr/86Sr = 0.7027, ɛNd = +5.6, ɛHf = +10) reflect the main phase of rifting during breakup of Rodinia and subsequent formation of volcanic island arcs. Granitoids forming the two principal domains of the BVM, the Slavkov Domain situated to the NE, and the Thaya domain situated to the SW, both intruded during the dominant magmatic activity at ∼ 600 Ma. The Sr–Nd–Pb–Hf isotope compositions of granitoids of the Slavkov Domain are typical of relatively primitive volcanic arc magmas. Thus, the Slavkov Domain may represent an eroded relic of a juvenile Neoproterozoic volcanic arc that developed above a subduction zone, very probably at an active Gondwanan margin of the Tornquist Ocean. Possibility of slab breakoff during arc formation cannot be ruled out. In contrast, the Thaya Domain originated by melting of Proterozoic mature continental crust above the same subducting slab at the Gondwanan margin. During subduction, significantly older remnants of an island arc (∼655 Ma Metadiorite Zone) and MORB-like volcanic rocks (∼740 Ma Metavolcanic Zone) were accreted to the continental margin, leading to the assemblage of the Brunovistulian microcontinent. Based on the depleted mantle Nd model ages, the lithosphere of the BVM has retained an isotope signature similar to Avalonia.

Název v anglickém jazyce

Origin of the Brunovistulian microcontinent: Geochemical and Sr-Nd-Pb-Hf isotope evidence

Popis výsledku anglicky

The Brunovistulian microcontinent (BVM) represents the largest (up to 30 000 km2) geological unit of Proterozoic provenance in the eastern part of the Variscan collision zone in Central Europe. We present whole-rock, mineral and Sr–Nd–Pb–Hf isotope compositions of representative samples from exposures and deep boreholes (up to 3 km in depth) situated in the Czech part of the BVM. The oldest rocks are ∼ 740 Ma Tonian basic metavolcanic rocks and associated felsic dykes and metatuffs of the Metavolcanic Zone. Geochemical and isotope characteristics of these felsic rocks confirm that their parent melts were derived from the upper mantle, similar to their metabasite hosts. The Tonian (Pan-African) age of the Metavolcanic Zone and its MORB-like geochemical and isotope signature (87Sr/86Sr = 0.7027, ɛNd = +5.6, ɛHf = +10) reflect the main phase of rifting during breakup of Rodinia and subsequent formation of volcanic island arcs. Granitoids forming the two principal domains of the BVM, the Slavkov Domain situated to the NE, and the Thaya domain situated to the SW, both intruded during the dominant magmatic activity at ∼ 600 Ma. The Sr–Nd–Pb–Hf isotope compositions of granitoids of the Slavkov Domain are typical of relatively primitive volcanic arc magmas. Thus, the Slavkov Domain may represent an eroded relic of a juvenile Neoproterozoic volcanic arc that developed above a subduction zone, very probably at an active Gondwanan margin of the Tornquist Ocean. Possibility of slab breakoff during arc formation cannot be ruled out. In contrast, the Thaya Domain originated by melting of Proterozoic mature continental crust above the same subducting slab at the Gondwanan margin. During subduction, significantly older remnants of an island arc (∼655 Ma Metadiorite Zone) and MORB-like volcanic rocks (∼740 Ma Metavolcanic Zone) were accreted to the continental margin, leading to the assemblage of the Brunovistulian microcontinent. Based on the depleted mantle Nd model ages, the lithosphere of the BVM has retained an isotope signature similar to Avalonia.

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

2025

Kód důvěrnosti údajů

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

Název periodika

Precambrian Research

ISSN

0301-9268

e-ISSN

1872-7433

Svazek periodika

428

Číslo periodika v rámci svazku

September

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

23

Strana od-do

107902

Kód UT WoS článku

001565789100001

EID výsledku v databázi Scopus

2-s2.0-105013956478