Assembly of the Variscan Orogenic Wedge in the Bohemian Massif: Monazite U-Pb Geochronology of the Tectonic Events Recorded in Saxothuringian Metasediments

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F23%3A10473417" target="_blank" >RIV/00216208:11310/23:10473417 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=ld13iYUM6q" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=ld13iYUM6q</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1029/2022TC007626" target="_blank" >10.1029/2022TC007626</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Assembly of the Variscan Orogenic Wedge in the Bohemian Massif: Monazite U-Pb Geochronology of the Tectonic Events Recorded in Saxothuringian Metasediments

Popis výsledku v původním jazyce

The geochronology of metasediments incorporated to orogenic wedges provides an important key in understanding the early evolution of collisional systems. This study reveals the timing of Variscan processes in the Saxothuringian orogenic wedge, reflecting transition from oceanic to continental subduction and collision. In situ monazite U-Pb geochronology and Rare Earth Elements (REE) geochemistry were performed in the Erzgebirge Crystalline Complex on phyllites and micaschists surrounding the ultra-high-pressure (UHP) core of the Erzgebirge dome. The resulting ages and REE patterns were linked to the individual tectonometamorphic events and revealed that the hanging-wall phyllites experienced prograde metamorphism around ~350 Ma, followed by exhumation at ~345-340 Ma. The oldest age (~339 Ma) recorded in garnet cores in the foot-wall micaschists is considered as an upper age limit for their prograde metamorphism, while matrix monazite ages of ~330 Ma reflect a significant resetting of the monazite age system. Spatial distribution of metamorphic isograds and ages indicates a phase of accretion of continental material resulting in an inverted metamorphic field gradient in the wedge between ~360 and ~340 Ma. This phase was followed by exhumation of a significant portion of buoyant subducted continental material leading to massive ductile thinning of the wedge around ~335 Ma. Finally, a late Variscan intracontinental deformation was responsible for heterogeneous reactivation and final exhumation of the wedge at ~330 Ma. It is newly shown that the Saxothuringian wedge can be divided into a younger inner part, formed by micaschists and UHP rocks, and an older outer part, formed by phyllites.

Název v anglickém jazyce

Assembly of the Variscan Orogenic Wedge in the Bohemian Massif: Monazite U-Pb Geochronology of the Tectonic Events Recorded in Saxothuringian Metasediments

Popis výsledku anglicky

The geochronology of metasediments incorporated to orogenic wedges provides an important key in understanding the early evolution of collisional systems. This study reveals the timing of Variscan processes in the Saxothuringian orogenic wedge, reflecting transition from oceanic to continental subduction and collision. In situ monazite U-Pb geochronology and Rare Earth Elements (REE) geochemistry were performed in the Erzgebirge Crystalline Complex on phyllites and micaschists surrounding the ultra-high-pressure (UHP) core of the Erzgebirge dome. The resulting ages and REE patterns were linked to the individual tectonometamorphic events and revealed that the hanging-wall phyllites experienced prograde metamorphism around ~350 Ma, followed by exhumation at ~345-340 Ma. The oldest age (~339 Ma) recorded in garnet cores in the foot-wall micaschists is considered as an upper age limit for their prograde metamorphism, while matrix monazite ages of ~330 Ma reflect a significant resetting of the monazite age system. Spatial distribution of metamorphic isograds and ages indicates a phase of accretion of continental material resulting in an inverted metamorphic field gradient in the wedge between ~360 and ~340 Ma. This phase was followed by exhumation of a significant portion of buoyant subducted continental material leading to massive ductile thinning of the wedge around ~335 Ma. Finally, a late Variscan intracontinental deformation was responsible for heterogeneous reactivation and final exhumation of the wedge at ~330 Ma. It is newly shown that the Saxothuringian wedge can be divided into a younger inner part, formed by micaschists and UHP rocks, and an older outer part, formed by phyllites.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GA17-22207S" target="_blank" >GA17-22207S: Role zděděné architektury kontinentálního okraje na ranně Variskou konvergenci</a><br>

Návaznosti

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

Rok uplatnění

2023

Kód důvěrnosti údajů

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

Název periodika

Tectonics

ISSN

0278-7407

e-ISSN

1944-9194

Svazek periodika

42

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

29

Strana od-do

e2022TC007626

Kód UT WoS článku

000973431700001

EID výsledku v databázi Scopus

2-s2.0-85153865589