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Aleksandra Gawęda, Krzysztof Szopa and David Chew

Abstract

This study presents apatite LA-ICP-MS U-Pb age and trace elements concentrations data from different granite types from the Tatra Mountains, Poland. Apatite from monazite and xenotime-bearing High Tatra granite was dated at 339 ± 5 Ma. The apatite LREE patterns reflect two types of magmas that contributed to this layered magma series. Apatite from a hybrid allanite-bearing diorite from the Goryczkowa Unit was dated at 340 ± 4 Ma with apatite LREE depletion reflecting the role of allanite and titanite during apatite crystallization. Apatite crystals from a hybrid cumulative rock from the Western Tatra Mountains were dated at 344 ± 3 Ma. Apatite is one of the main REE carriers in this sample and exhibit flat REE patterns.

Taking into account the relatively low closure temperature of the U-Pb system in apatite (350–550°C), the c. 340 Ma apatite ages mark the end of high temperature tectonometamorphic activity in the Tatra Mountains.

Open access

Paulina Pyka, Krzysztof Szopa and Aleksandra Gawęda

Abstract

Large crystals of kyanite (<15 cm in size) occur in quartz segregations in Paleozoic gneissses on Baranec Mt., Western Tatra Mountains, northern Slovakia. Blue kyanite crystals coexist with quartz and plagioclase. The kyanite contains inclusions of apatite, monazite. gamet, rutile and biotite and overgrowths of retrograde sillimanite. muscovite and biotite. The kyanite crystals are the largest found up to now in the Tatra crystalline massif or in the other Western Carpathians crystalline cores. Kyanite. with the co-existing mineral assemblage, is indicative of a HP stage duiing Hercynian metamorphism of the Western Tatra Mountains.

Open access

Aleksandra Gawęda, Krzysztof Szopa, David Chew, Urs Klötzli, Axel Müller, Magdalena Sikorska and Paulina Pyka

Abstract

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.

Open access

Jolanta Burda, Aleksandra Gawęda and Urs Klötzli

Abstract

The geochemical characteristics as well as the LA-MC-ICP-MS U-Pb zircon age relationship between two granitoid suites found in the Goryczkowa crystalline core in the Western Tatra Mountains were studied. The petrological investigations indicate that both granitoid suites were emplaced at medium crustal level, in a VAG (volcanic arc granites) tectonic setting. However, these suites differ in source material melted and represent two different magmatic stages: suite 1 represents a high temperature, oxidized, pre-plate collision intrusion, emplaced at ca. 371 Ma while suite 2 is late orogenic/anatectic magma, which intruded at ca. 350 Ma. These data are consistent with a period of intensive magmatic activity in the Tatra Mountain crystalline basement. The emplacement of granitoids postdates the LP-HT regional metamorphism/ partial melting at ca. 387 Ma and at 433-410 Ma, imprinted in the inherited zircon cores.

Open access

Paulina Pyka, Aleksandra Gawęda, Krzysztof Szopa, Axel Müller and Magdalena Sikorska

Abstract

In the Tatra Mountains (Slovakia) metamorphic complex, kyanite-quartz segregations with biotite-rich selvage occur in mylonitized mica schists. In this paper, the problem of fluid flow and aluminium mobility during the uplift of the crystalline massif, and the position of the segregations in the history of Western Tatra metamorphic complex, is adressed. The reaction Alm + Rt ➔ Ilm + Ky + Qtz is considered to be the result of a pressure drop from above to below 9 kbar. Ti-in-biotite geothermometry shows the temperature range to be 579-639°C that is related to heating and decompression associated with granite intrusion. Major-element mass-balance calculations show that Al remained stable in the selvage + segregation system whereas other elements (e.g. Cr, HFSE) were mobilized. The kyanite-quartz segregations formed from local fluids generated during dehydration of the metapelitic rocks during uplift. The main mechanism was likely diffusion-driven mass-transfer into extension-related cracks.

Open access

Jolanta Burda, Aleksandra Gawęda and Urs Klötzli

Abstract

Detailed cathodoluminescence (CL) imaging of zircon crystals, coupled with Laser Ablation Multi-Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) U-Pb zircon dating was used to develop new insights into the evolution of granitoids from the High Tatra Mountains. The zircon U-Pb results show two distinct age groups (350±5 Ma and 337±6 Ma) recorded from cores and rims domains, respectively. Obtained results point that the last magmatic activity in the Tatra granitoid intrusion occurred at ca. 330 Ma. The previously suggested age of 314 Ma reflects rather the hydrothermal activity and Pb-loss, coupled with post-magmatic shearing.