ASGP (2019), vol. 90: 27–49

AGE CONSTRAINTS ON THE PRE-VARISCAN AND VARISCAN THERMAL EVENTS IN THE KAMIENIEC ZĄBKOWICKI METAMORPHIC BELT (THE FORE-SUDETIC BLOCK, SW POLAND)

Mirosław JASTRZĘBSKI (1)*, Andrzej ŻELAŹNIEWICZ (1), Bartosz BUDZYŃ (2), Jiří SLÁMA (3) & Patrik KONEČNÝ (4)

1) Institute of Geological Sciences, Polish Academy of Sciences, Research Centre in Wrocław, ul. Podwale 75, 50-449 Wrocław, Poland; e-mails: mjast@twarda.pan.pl, pansudet@pwr.edu.pl
2) Institute of Geological Sciences, Polish Academy of Sciences, Research Centre in Kraków, ul. Senacka 1, 31-002 Kraków, Poland; e-mail: ndbudzyn@cyf-kr.edu.pl
3) The Czech Academy of Sciences, Institute of Geology, Rozvojová 269, Prague 6, 16500, Czech Republic; e-mail: slama@gli.cas.cz
4) Dionýz Štúr State Geological Institute, Mlynská dolina 1, SK-81704 Bratislava, Slovak Republic; e-mail: patrik.konecny@geology.sk
* Corresponding author

Jastrzębski, M., Żelaźniewicz, A., Budzyń, B., Sláma, J. & Konečny, P., 2020. Age constraints on the Pre-Variscan and Variscan thermal events in the Kamieniec Ząbkowicki Metamorphic belt (the Fore-Sudetic Block, SW Poland). Annales Societatis Geologorum Poloniae, 90: 27 – 49.

Abstract: The Kamieniec Ząbkowicki Metamorphic Belt (KZMB) is a narrow zone of mainly mica schists, subordinate acid metavolcanics and scarce eclogites, sandwiched between Brunovistulia and the northern tip of the Teplá-Barrandia microplates. Locally occurring high-pressure relics indicate subduction of the metasedimentary succession of the KZMB, the origin and provenance of which remain unclear. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) investigations of detrital zircons show that the metapelites represent an Ediacaran-Cambrian sedimentary basin, with a maximum depositional age of 561±9 Ma. This basin was filled with detritus from a source or sources, composed of rocks containing zircons that are mainly Cryogenian-Ediacaran and Palaeoproterozoic in age. No younger component was found in the zircon population studied. The isotopic U-Pb LA-ICP-MS and chemical U-Th-total Pb electron probe microanalysis (EPMA) monazite geochronology data indicate an important regional tectono-metamorphic event at ca. 330 Ma. Though these data do not permit determination of the peak pressure from the peak temperature stages, the event was part of a complex collision of the Saxothuringian plate with Brunovistulia.

Manuscript received 25 March 2020, accepted 1 June 2020

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