New constraints on the tectonometamorphic evolution of the Erzgebirge orogenic wedge (Saxothuringian Domain, Bohemian Massif)

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F22%3A10457187" target="_blank" >RIV/00216208:11310/22:10457187 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=DuWs-uD6tc" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=DuWs-uD6tc</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1111/jmg.12643" target="_blank" >10.1111/jmg.12643</a>

Result language

angličtina

Original language name

New constraints on the tectonometamorphic evolution of the Erzgebirge orogenic wedge (Saxothuringian Domain, Bohemian Massif)

Original language description

In contrast to well-documented (U)HP rocks of the Erzgebirge crystalline complex (Saxothuringian Domain, Bohemian Massif), the surrounding medium- to low-grade metasediments are scarcely studied, although they provide an important link between deep subduction and mid-crustal processes. To constrain the Variscan evolution from continental subduction to orogenic wedge, the transition from the low-grade phyllites to the footwall medium-grade micaschists was investigated. We used thermodynamic modelling to constrain the P-T conditions of four deformation fabrics (D1-D4) identified by the structural analysis. The studied area was first affected by the M1-D1 event characterized by HP-LT minerals (garnet, chloritoid, phengite, paragonite, and rutile) defining the S1 foliation. The calculated peak P-T conditions for M1 increase from 13 kbar and 520°C in phyllites to 25 kbar and 560°C in micaschists. The corresponding apparent geothermal gradient 6-11°C/km is typical for a subduction environment. The M2-D2 event corresponds to deformation and metamorphic overprint of the previous fabric during partial decompression. The M3-D3 event is mainly developed in micaschists, and the M3 overprint intensifies towards the footwall. It is accompanied by a subhorizontal S3 cleavage characterized by MP-MT assemblage containing biotite, staurolite and ilmenite. The inferred peak P-T conditions for M3 are 5-9 kbar and 595°C representing a barrovian-type geothermal gradient from 17-30°C/km. Finally, all metamorphic fabrics were heterogeneously affected by the low-grade M4-D4 upright folding. The D1-D2 events are interpreted to record the growth and evolution of the Saxothuringian orogenic wedge while its present-day architecture resulted from significant vertical shortening D3 associated with barrovian type M3-metamorphism. This stage corresponds to the ductile thinning of the wedge. A new model is proposed, in which the Erzgebirge part of the Saxothuringian Domain reveals a spectacular example of active margin evolution characterized by (i) formation of accretionary prism, (ii) building of the orogenic wedge by accretion of subducted continental crust, and (iii) its extensional collapse.

Czech name

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Czech description

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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/GA17-22207S" target="_blank" >GA17-22207S: The role of inherited continental margin architecture on early Variscan convergence</a><br>

Continuities

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

Publication year

2022

Confidentiality

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

Name of the periodical

Journal of Metamorphic Geology

ISSN

0263-4929

e-ISSN

1525-1314

Volume of the periodical

40

Issue of the periodical within the volume

4

Country of publishing house

GB - UNITED KINGDOM

Number of pages

29

Pages from-to

687-715

UT code for WoS article

000728748200001

EID of the result in the Scopus database

2-s2.0-85117734972