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Age and origin of fluorapatite-rich dyke from Baranec Mt. (Tatra Mts., Western Carpathians)

Untertitel:A key to understanding of the post-orogenic processes and element mobility
Autoren:Gawȩda, Aleksandra (University of Silesia in Katowice) Szopa, Krzysztof (University of Silesia in Katowice) Chew, David (Universität Wien) Klötzli, Urs (Trinity College Dublin) Müller, Axel (University of Oslo (UiO)) Sikorska, Magdalena (Polish Geological Institute-Polish Research Institute) Pyka, Paulina (University of Silesia in Katowice)

On the southeastern slope of the Baranec Mount in the Western Tatra Mountains (Slovakia) an apatite-rich pegmatite-like segregation was found in the subvertical fault zone cutting metapelitic rocks. Two zones: felsic (F) and mafic (M) were found, differing in mineral assemblages and consequently in chemistry. Fluorapatite crystals yield a LA-ICP-MS U-Pb age of 328.6 ± 2.4 Ma. A temperature decrease from 634 °C to 454 °C at a pressure around 500 to 400 MPa with oxygen fugacity increasing during crystallization are the possible conditions for formation of the pegmatite-like segregation, while secondary alterations took place in the temperature range of 340-320 °C. The Sr-Nd isotope composition of both apatite and whole rock point toward a crustal origin of the dike in question, suggesting partial melting of (P, F, H2O)-rich metasedimentary rocks during prolonged decompression of the Tatra Massif. The original partial melt (felsic component) was mixed with an external (F, H2O)-rich fluid, carrying Fe and Mg fluxed from more mafic metapelites and crystallizing as biotite and epidote in the mafic component of the dyke.

Anzahl der Seiten:16
Journal Titel:Geologica Carpathica
Digital Object Identifier (DOI):https://doi.org/10.1515/geoca-2016-0026
Publikations Typ:Artikel
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