Tectonic evolution and global crustal architecture of the European Variscan belt constrained by geophysical data

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F22%3A00000166" target="_blank" >RIV/00025798:_____/22:00000166 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/abs/pii/S0012825222002793?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/abs/pii/S0012825222002793?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.earscirev.2022.104195" target="_blank" >10.1016/j.earscirev.2022.104195</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Tectonic evolution and global crustal architecture of the European Variscan belt constrained by geophysical data

Popis výsledku v původním jazyce

The European Variscan belt is a unique orogen that is covered by comprehensive sets of seismic and potentialfield data from the Iberian Peninsula in the west to the Polish Sudetes in the east. The combination of both allowsfor a new interpretation of the structure and evolution of the European Variscides at the continental scale. TheEuropean Variscan belt has been divided into three domains according to distinct geological and geophysicalcharacteristics: 1) the North-eastern Variscan Domain (NVD) outcropping in the Bohemian Massif, Black Forestand Vosges Massifs, and the Rhenish Massif, 2) the Central Variscan Domain (CVD) represented by the FrenchMassif Central, Armorican Massif and British Variscides, and 3) The South-western Variscan Domain (SVD)represented by the Iberian Massif. The gravity data show the presence of high amplitude, short-wavelengthgravity anomalies that are mainly correlated with the outcrops of eclogites, ultramafic rocks and ophiolites.These anomalies locate the main body of the Mid-Variscan Allochthon in the SVD and CVD and the DevonianMid-Variscan suture in the NVD. The gravity data also show medium amplitude elongated long-wavelengthgravity highs aligned parallel to the structural grain of the Variscan belt, represented by the deformed Tepl´a-Barrandian-Kraichgau upper crustal rocks, a Devonian supra-subduction basin in the Mid-Variscan Allochthon,and the autochthonous rocks of the Central Iberian Zone in the SVD, the Armorican Massif in the CVD and theSaxothuringian Zone in the NVD. The short wavelength negative gravity anomalies are mainly developed in thecentral part of the belt and coincide with Carboniferous (330–310 Ma) per- to meta-aluminous magmatic bodies,pre-Variscan orthogneisses and Carboniferous felsic granulite bodies. Noticeably, Permian (300–290 Ma) granitoidsdo not reveal any gravity lows indicating that these bodies are not deeply rooted. The magnetic data showtwo belts correlated to Carboniferous Rhenohercynian and Devonian Mid-Variscan magmatic arc granitoids. TheRhenohercynian and Mid-Variscan subduction systems are well imaged by moderately SE dipping primary A-typereflectors in reflection seismic lines in the NVD and CVD, while in the SVD the reflectors related to the Rhenohercyniansubduction are dipping to the NE and the seismic signature of the Mid-Variscan suture is weaklydeveloped. In the NVD, a third belt of SE-dipping reflectors is attributed to the Carboniferous subduction of theSaxothuringian continental lithosphere beneath the Mid-Variscan Allochthon. Younger B-type moderately dippingreflectors in the upper-middle crust coincide with outcrops of Carboniferous detachments, sometimeslimiting granite plutons and core complexes along-strike the core of the Variscan orogeny. C-type reflectors occurmainly in the deep crust and are considered as an expression of lower crustal flow resulting from extensional reequilibrationof the previously thickened Variscan crust. A synthesis of P-wave velocity logs at the scale of thewhole Variscan belt shows the existence of three different continental crusts: (i) cratonic crust marked by a thick,high velocity lower crust, (ii) transitional crust characterised by a relatively thin high velocity lower crust andintermediate velocity middle crust, and (iii) a thin Variscan orogenic crust defined by low velocity lower andmiddle crust. The latter crustal type coincides with regional outcrops of 330–310 Ma per- to meta- aluminousgranitoids and associated gravity lows along-strike the belt. It is argued that the specific “Variscan” orogenic crust originated by Carboniferous extensional thinning and extensive melting of previously thickened “Tibetan”type crust and not from Permian tectogenesis, which is restricted to marginal parts of the orogen.

Název v anglickém jazyce

Tectonic evolution and global crustal architecture of the European Variscan belt constrained by geophysical data

Popis výsledku anglicky

The European Variscan belt is a unique orogen that is covered by comprehensive sets of seismic and potentialfield data from the Iberian Peninsula in the west to the Polish Sudetes in the east. The combination of both allowsfor a new interpretation of the structure and evolution of the European Variscides at the continental scale. TheEuropean Variscan belt has been divided into three domains according to distinct geological and geophysicalcharacteristics: 1) the North-eastern Variscan Domain (NVD) outcropping in the Bohemian Massif, Black Forestand Vosges Massifs, and the Rhenish Massif, 2) the Central Variscan Domain (CVD) represented by the FrenchMassif Central, Armorican Massif and British Variscides, and 3) The South-western Variscan Domain (SVD)represented by the Iberian Massif. The gravity data show the presence of high amplitude, short-wavelengthgravity anomalies that are mainly correlated with the outcrops of eclogites, ultramafic rocks and ophiolites.These anomalies locate the main body of the Mid-Variscan Allochthon in the SVD and CVD and the DevonianMid-Variscan suture in the NVD. The gravity data also show medium amplitude elongated long-wavelengthgravity highs aligned parallel to the structural grain of the Variscan belt, represented by the deformed Tepl´a-Barrandian-Kraichgau upper crustal rocks, a Devonian supra-subduction basin in the Mid-Variscan Allochthon,and the autochthonous rocks of the Central Iberian Zone in the SVD, the Armorican Massif in the CVD and theSaxothuringian Zone in the NVD. The short wavelength negative gravity anomalies are mainly developed in thecentral part of the belt and coincide with Carboniferous (330–310 Ma) per- to meta-aluminous magmatic bodies,pre-Variscan orthogneisses and Carboniferous felsic granulite bodies. Noticeably, Permian (300–290 Ma) granitoidsdo not reveal any gravity lows indicating that these bodies are not deeply rooted. The magnetic data showtwo belts correlated to Carboniferous Rhenohercynian and Devonian Mid-Variscan magmatic arc granitoids. TheRhenohercynian and Mid-Variscan subduction systems are well imaged by moderately SE dipping primary A-typereflectors in reflection seismic lines in the NVD and CVD, while in the SVD the reflectors related to the Rhenohercyniansubduction are dipping to the NE and the seismic signature of the Mid-Variscan suture is weaklydeveloped. In the NVD, a third belt of SE-dipping reflectors is attributed to the Carboniferous subduction of theSaxothuringian continental lithosphere beneath the Mid-Variscan Allochthon. Younger B-type moderately dippingreflectors in the upper-middle crust coincide with outcrops of Carboniferous detachments, sometimeslimiting granite plutons and core complexes along-strike the core of the Variscan orogeny. C-type reflectors occurmainly in the deep crust and are considered as an expression of lower crustal flow resulting from extensional reequilibrationof the previously thickened Variscan crust. A synthesis of P-wave velocity logs at the scale of thewhole Variscan belt shows the existence of three different continental crusts: (i) cratonic crust marked by a thick,high velocity lower crust, (ii) transitional crust characterised by a relatively thin high velocity lower crust andintermediate velocity middle crust, and (iii) a thin Variscan orogenic crust defined by low velocity lower andmiddle crust. The latter crustal type coincides with regional outcrops of 330–310 Ma per- to meta- aluminousgranitoids and associated gravity lows along-strike the belt. It is argued that the specific “Variscan” orogenic crust originated by Carboniferous extensional thinning and extensive melting of previously thickened “Tibetan”type crust and not from Permian tectogenesis, which is restricted to marginal parts of the orogen.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GX19-27682X" target="_blank" >GX19-27682X: Hlavní mechanismy periferálního kontinentálního růstu během superkontinentálního cyklu</a><br>

Návaznosti

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

Rok uplatnění

2022

Kód důvěrnosti údajů

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

Název periodika

Earth-Science Reviews

ISSN

0012-8252

e-ISSN

—

Svazek periodika

234

Číslo periodika v rámci svazku

November : 104195

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

44

Strana od-do

nestránkováno

Kód UT WoS článku

000880673300001

EID výsledku v databázi Scopus

2-s2.0-85140899748