Eo-Variscan metamorphism in the Bohemian Massif: Thermodynamic modelling and monazite geochronology of gneisses and granulites of the Góry Sowie Massif, SW Poland

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F21%3A00545392" target="_blank" >RIV/67985831:_____/21:00545392 - isvavai.cz</a>

Result on the web

<a href="https://onlinelibrary.wiley.com/doi/epdf/10.1111/jmg.12589" target="_blank" >https://onlinelibrary.wiley.com/doi/epdf/10.1111/jmg.12589</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1111/jmg.12589" target="_blank" >10.1111/jmg.12589</a>

Result language

angličtina

Original language name

Eo-Variscan metamorphism in the Bohemian Massif: Thermodynamic modelling and monazite geochronology of gneisses and granulites of the Góry Sowie Massif, SW Poland

Original language description

In the Variscides of central Europe, the tectonothermal history of a few units jointly assigned to the Teplá-Barrandian/Bohemian microplate had already terminated in the Devonian. One of these is the Góry Sowie Massif (GSM, Sudetes, SW Poland), mainly consisting of variably migmatitic gneisses with subordinate granulite and peridotite inserts. The eo-Variscan evolution of the GSM was completed in five tectonothermal stages, however, the timing and pressure–temperature (P–T) conditions of the individual stages remain unclear because isotopic ages overlap within error, and previous P–T estimates have been determined without reference to these ages. Our thermodynamic modelling and LA–ICP–MS U–Pb and electron probe microanalysis (EPMA) U–Th–total Pb monazite geochronology provide new insights into the early Variscan multistage evolution of the GSM. The new P–T–time (t) data show that granulites were metamorphosed concurrently with gneisses but at different depths and temperatures. During subduction of Saxothuringia beneath Teplá-Barrandia at 395–390 Ma, the granulites of crustal provenance experienced high-P–high-T conditions (740–750°C, 17–18 kbar) and came in contact with the overlying mantle. Slab break-off gave rise to decompression from conditions of ~17 kbar/840°C to 11–12 kbar/850–860°C, which continued at 380–370 Ma when the granulites were sheared off and extruded as tectonic slices to lower–middle crustal depths, where gneisses were undergoing metamorphism and migmatization under amphibolite facies conditions. In the gneisses, the oldest monazite date of c. 390 Ma constrains the age of the early tectonometamorphic event D1. Two subsequent events (D2 and D3, sillimanite grade) occurred under conditions of 660–680°C and 5–9 kbar at 380–375 Ma, when, in various parts of the future massif, the gneisses were (re)folded and migmatized due to heat arising from underplated mantle. Isostatic exhumation was accompanied by pegmatite intrusions (D4) at 370 Ma and subsequent orogenic collapse (D5). Concurrently, high temperature conditions (~700°C) promoted a disturbance of the U–Pb system in monazite in some granulites.

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

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OECD FORD branch

10505 - Geology

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2021

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

39

Issue of the periodical within the volume

6

Country of publishing house

GB - UNITED KINGDOM

Number of pages

29

Pages from-to

751-779

UT code for WoS article

000634390800001

EID of the result in the Scopus database

2-s2.0-85103209880