High pressure melting of metagranitoids in continental subduction: implication for the Eger and Kutná hora crystalline complexes in Bohemian Massif

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

High pressure melting of metagranitoids in continental subduction: implication for the Eger and Kutná hora crystalline complexes in Bohemian Massif

Popis výsledku v původním jazyce

The Eger (ECC) and Kutná Hora crystalline complexes (KHC) in the Bohemian Massif are dominated by high-grade anatectic rocks as orthogneisses, migmatites, granites, felsic granulites and eclogites. They represent felsic orogenic lower crust that was exhumed during the Variscan orogeny at around 340 Ma. The ECC is part of the Saxothuringian zone and peak conditions for the anatectic gneisses and granulites were estimated at 650-720°C at 15-30 kbar, whereas KHC is situated in the Moldanubian zone and peak conditions for the anatectic gneisses and granulites were estimated at ca. 850°C at 15kbar. The rocks of ECC and KHC reveal textural variations from stromatic migmatite, inhomogeneous diatexite to isotropic granitic gneiss and granite reflecting different degree of migmatization. Field relationships suggest that these rocks represent a continuous textural sequence and are all derived from the same protolith, biotite-muscovite granite. In this study, we aim to understand timing, conditions, type and consequences of the high pressure partial melting in a subduction setting. We suggest that rocks in both units underwent localized melting at high pressure, with the felsic granulites representing a part of the system that was not hydrated at high pressure, therefore remained dry and did not undergo apparent melting. Resulting high pressure melts are granitic in composition, no further melting occurred during decompression in mid-crustal levels. Moreover, we suggest that the Kutná hora high-grade anatectic rocks are derived from the Saxothuringian protolith that was added to the bottom of the upper crust either by relamination or by plume-like ascent of previously subducted crust.

Název v anglickém jazyce

High pressure melting of metagranitoids in continental subduction: implication for the Eger and Kutná hora crystalline complexes in Bohemian Massif

Popis výsledku anglicky

The Eger (ECC) and Kutná Hora crystalline complexes (KHC) in the Bohemian Massif are dominated by high-grade anatectic rocks as orthogneisses, migmatites, granites, felsic granulites and eclogites. They represent felsic orogenic lower crust that was exhumed during the Variscan orogeny at around 340 Ma. The ECC is part of the Saxothuringian zone and peak conditions for the anatectic gneisses and granulites were estimated at 650-720°C at 15-30 kbar, whereas KHC is situated in the Moldanubian zone and peak conditions for the anatectic gneisses and granulites were estimated at ca. 850°C at 15kbar. The rocks of ECC and KHC reveal textural variations from stromatic migmatite, inhomogeneous diatexite to isotropic granitic gneiss and granite reflecting different degree of migmatization. Field relationships suggest that these rocks represent a continuous textural sequence and are all derived from the same protolith, biotite-muscovite granite. In this study, we aim to understand timing, conditions, type and consequences of the high pressure partial melting in a subduction setting. We suggest that rocks in both units underwent localized melting at high pressure, with the felsic granulites representing a part of the system that was not hydrated at high pressure, therefore remained dry and did not undergo apparent melting. Resulting high pressure melts are granitic in composition, no further melting occurred during decompression in mid-crustal levels. Moreover, we suggest that the Kutná hora high-grade anatectic rocks are derived from the Saxothuringian protolith that was added to the bottom of the upper crust either by relamination or by plume-like ascent of previously subducted crust.

Druh

D - Stať ve sborníku

CEP obor

DB - Geologie a mineralogie

OECD FORD obor

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Projekt

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Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

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

Název statě ve sborníku

CETEG 2016 14th Meeting of the Central European Tectonic Group - Abstract Volume

ISBN

978-80-223-4071-7

ISSN

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e-ISSN

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Počet stran výsledku

2

Strana od-do

62-63

Název nakladatele

Univerzita Komenského Bratislava

Místo vydání

Bratislava

Místo konání akce

Predná Hora Slovakia

Datum konání akce

28. 4. 2016

Typ akce podle státní příslušnosti

EUR - Evropská akce

Kód UT WoS článku

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